Low Dose Of hCG Research Articles

P–671 Dual Trigger(low adjuvant HCG4h after GnRHagonist trigger)have positive impact of overall embryo’s quality, implantation ,clinical pregnancy and live birth rates in high-risk patients for OHSS

Abstract Study question Study aim is to compare implantation,clinical pregnancy and livebirth rates between giving1500IU of hCG4hours after GnRHagonist,on trigger day or GnRHagonist as alone trigger with luteal support withHCG1500IU.35h later on OPUday. Summary answer Adjuvant doze of1500IUhCG4h after bolus of GnRHagonist on trigger day significantly improve quality of blastocyst,implantation,clinical pregnancy and live birth rates without increasing the risk ofOHSS. What is known already The use of GnRHagonist for final oocyte maturation in antagonist cycle significantly decrease the incidence of OHSS,but there have been studies showing lower pregnancy rates in patients triggered with GnRHagonist compared with hCG in autologous cycles,attributed to a defective luteal phase, especially in high–risk patients despite intensive luteal phase support.To improve the results of IVF,an alternative approach is adding a small bolus dose of hCG(1500IU)35h later,on the OPU day after GnRHagonist trigger which provides more sustained support for the corpus luteum.The question is does low doses of hCGgiven on the same day with GnRHagonist trigger is making better quality oocytes. Study design, size, duration Single center prospective longitudinal cohort study fromJanuary2017 to Decembar2019.The initial inclusion criteria were:women age≥18and≤39years,AMH≥3,3ng/ml and ≥12 antral follicles on basal ultrasound.Patients with history of OHSS and PCO are also included in the study.Patients with applied “freeze-all” technique with peak estradiol≥4000pg/ml on trigger day>18oocytes on the OPU day,and recognized significant risk for developing OHSS were also included.The cumulative implantation,clinical pregnancy and live birth rates were analyzed,only in embryos from the same COS protocol in every patient. Participants/materials, setting, methods A total of 231 patients were entered for final analysis,who underwent a flexible antagonist protocol,ICSI and fresh or thawed ET on 3th(38.53%) or 5th( 61.47%)day in women’s autologous cycles.Patients were randomized in one of two groups: GroupA-Dual trigger group 1500IUof hCG 4h after GnRH agonist application on trigger day and GroupB –1500IU of HCG 35h later,on the OPU day.We used nonparametric and parametric statistical tests.Significant differences were considered all values ​​of p < 0.05 Main results and the role of chance Both groups are homogenous regarding several variables:age,BMI,type of sterility,smoking status,AMH,PCO, spermogram.There is no significant difference between the two(AvsB)groups according to average number of retrieved oocytes(13.6 vs 14.6 p > 0,05),M II oocytes(11.03 vs 11.99 p > 0.05).The dual trigger group(A)had a higher fertility rate(69.99% vs 64.11% p < 0,05)compared with GnRHagonist trigger group(B).There are no significant difference between groups(AvsB)according to cumulative average number of:transferred embryos(2.4vs2.5 p > 0.05)TQE transfered on 3th day(1.5.vs 1.3.p>0.05);transferred blastocyst(2.6 vs2.7 >0.05);cryo embryos(2.5vs1.9 p > 0.05),but there are significant difference according to cumulative implantation rate of transferred blastocyst in favor of group A(48.18% vs 33.89%p<0.05).Analyzes of morphological characteristics of transferred blastocyst depicted in the order of degree of blastocyst expansion,inner cellular mass(ICM)and trofoectoderm(TE) and ranking overall blastocysts quality from“excellent”,“good”,“average” and “pore” ,shows that there are significantly more percentage of patient with embryo transfer of “excellent” or even one “excellent” blastocyst in group A (30.56%,31.94% vs 21.54%,23.08% p < 0.05) in opposite of percentage of patients with embryo transfer with “poore “” blastocyst in group B (37.5% vs 46.15.%p<0.05). Clinical pregnanacy rate (71.68% vs 50.84% p < 0.05) , and live birth rate (60,18% vs 42,58% ), were significantly higher in group A. There were no cases of moderate or severe OHSS in both groups. Limitations, reasons for caution Dual trigger in GnRH antagonist protocols should be advocated as a safe approach but undetected high risk patients are reasons for caution for developing clinically significant OHSS. Wider implications of the findings: Adjuvant low dose of hCG on GnRHagonist trigger day improve clinical pregnancy and live birth rates without increasing the risk of clinically significant OHSS.Protocol of dual trigger and freezing all oocytes or embryos in patients with high risk of developing OHSS is promising technique in everyday practice. Trial registration number 8698

PSXII-36 Use of FSH or hCG to enhance follicular growth and pregnancy per artificial insemination during a split-AI program in crossbreed beef heifers

Abstract The objective of the study was to compare follicle growth and pregnancy per artificial insemination (P/AI) in crossbreed heifers receiving either a low dose of hCG (150 IU) or a low dose of FSH (20 mg) vs. a control group during the final stage of a split-AI protocol. A total of 387 heifers were enrolled in the trial and were randomly assigned in three treatments (Control n = 134, FSH n = 125, and hCG n =128) within reproductive tract score (RTS; 1 to 5 scale), body condition score (BCS; 1 to 9 scale) and pubertal status. All groups were synchronized with a 7-day CO-Synch + CIDR protocol, at CIDR removal the two treatments were injected, an Estrotect patch was placed, and the diameter of the dominant follicle was assessed through transrectal ultrasonography, at day 9 heifers that presented estrus (> 50% of the Estrotect patch rubbed off) were AI, and those that did not were TAI at day 10. An ultrasound was carried out along with the AI to measure the diameter of the preovulatory follicle and 30 days after for pregnancy check. The data was analyzed using the GLIMMIX procedure (SAS). The diameter of the preovulatory follicle was different among treatments (Control: 11.48 ± 0.21; FSH: 11.48 ± 0.25; hCG; 10.73 ± 0.28; P = 0.01). However, the rate of follicular growth (Control: 4.96 ± 0.37; FSH: 4.59 ± 0.39; hCG: 5.12 ± 0.38; P = 0.64) and P/AI (control: 41.35%; FSH: 35.77%; and hCG: 34.38%; P = 0.47) were not different among groups. There was a significant difference (P < .0001) in P/AI when comparing animals that presented estrous (48.99%) or not (29.27%). In conclusion, the use of low dosed of hCG or FSH at the time of device removal did not increase the proportion of pregnant heifers.

Combining several interventions to reduce the incidence of OHSS: A prospective cohort study

ObjectiveTo assess the outcome of using low-dose aspirin, dopamine agonist and triggering ovulation by low dose of HCG in combination with GnRH agonist in fixed GnRH antagonist protocol in patients at risk of OHSS. Study designThis prospective cohort study was conducted on 50 infertile women who were at high risk of OHSS. They received low dose aspirin from first day of stimulation, cabergoline 0.5mg daily from the day of HCG for 8days and low dose of HCG (2500 IU) in combination with GnRH agonist for final oocyte maturation in fixed GnRH antagonist protocol. ResultsThe study was conducted on 50 cases and all of them completed the study protocol. The clinical pregnancy rate was 40% (20 cases of 50) and no cases developed severe or critical OHSS. Only 8% (4 cases) developed moderate OHSS. ConclusionCombining aspirin, cabergoline, and triggering with low dose of HCG in combination with GnRH agonist produced excellent clinical pregnancy rate, and decreased hospital admissions with severe or critical OHSS.

10 TIMED ARTIFICIAL INSEMINATION PROTOCOLS TO SYNCHRONIZATION OF OVULATION IN BOS TAURUS TAURUS SUCKLING BEEF COWS

The aim of this study was to compare 3 methods for synchronization of ovulation in anestrous beef cows. The hypothesis of this study was to determine whether low doses of hCG has superior efficacy to cypionate to induce ovulation in anestrous cows and provide higher pregnancy rate in oestrus-synchronization programs. Synchronization of ovulation and conception rate to timed AI (TAI) were evaluated in anestrus Bos taurus taurus suckling beef cows 45 ± 15 days postpartum and with body condition score of 2.9 (1 to 5) maintained in a native pastured system in the south of Brazil. Females were evaluated with ultrasound on the Day 0 (D0) of the protocol (Day 0), day 8 (D8), immediately before TAI (D10), and 7 days after TAI (Day 17). All cows were synchronized with an intravaginal progesterone-releasing device (IPRD; 0.75 g of progesterone, Prociclar®, Hertape Calier Animal Health, Juatuba, Brazil) and 2 mg IM of oestradiol benzoate (EB; Benzoato HC®) on D0. On Day 8, the IPRD was removed and 150 μg of D (+) cloprostenol (Veteglan Luteolytic®), and 25 IU IM FSH/LH (Pluset®) were administered. Females of the EC (n = 84) group received 1 mg IM of oestradiol cypionate (EC; Cipionato HC®). Females on D8 of the hCG (n = 81) group received 500 IU IM of hCG (Vetecor®, Hertape Calier) at the time of TAI. The females of the EC + hCG group (n = 83) received both treatments. All cows were submitted to TAI 54 h after withdrawal of IPRD. A part of the cows (n = 102) had the ovulation evaluated every 12 h from the withdrawal of IPRD [EC (n = 34), hCG (n = 34), and hCG + EC (n = 33)]. Statistical analysis was performed using SAS PROC GLIMMIX. The dominant follicle diameter (FD) on Day 8 (8.7 ± 0.2, 8.8 ± 0.2, 8.6 ± 0.2) did not differ between treatments EC, EC + hCG, or hCG (P = 0.79). However, the FD on D10 was higher (P = 0.001) for cows treated with hCG (12.9 ± 0.3) compared with cows from the EC (11.3 ± 0.2) or EC + hCG group (11.8 ± 0.2). The interval (h) between the withdrawal of IPRD and ovulation was lower (P = 0.01) for the hCG group, (71.2 ± 1.7) compared with the groups treated with EC or EC + hCG (76.6 ± 2.18 and 74.2 ± 1.65), respectively. The ovulation rate did not differ (P = 0.61) among the EC (85.2%, 29/34), hCG (91.1%, 31/34), or EC + hCG groups (90.9%, 30/33). Corpus luteum diameter (mm) was higher (P = 0.04) on D17 for the hCG-treated group (21.4 ± 0.3) compared with others treatments (EC = 19.1 ± 0.8 or EC + hCG = 20.4 ± 0.8). However, the plasma progesterone levels on D17 were EC = 2.0 ± 0.1, hCG = 2.4 ± 0.1, and EC + hCG = 2.3 ± 0.1 ng mL–1 (P = 0.19), and the conception rate on the 28th day after TAI (EC = 43.0%; hCG = 47.0%, and EC + hCG = 48.8%; P = 0.76) was also similar. The hCG determined smallest ovulation interval, but similar rates of pregnancy were observed with both treatments.

Spawning Latency Period in Hormonal Induced Reproduction of Snow trout (Schizothorax zarudnyi (Nikolskii, 1897))

Background The breeding performance is an important parameter to evaluate the breeding success in captivity conditions. The optimum dose of hormone in combination with latency period is desirable for getting best breeding performance in fish..Objectives The objective of the study was to find the spawning latency period in the hormonal induced reproduction of Snow trout with two inducers (Ovaprim and hCG) separately and in combination. Materials And Methods The fish spawners were randomly divided into five groups and treated with Ovaprim, Ovaprim and high dose of hCG, Ovaprim and low dose ofhCG, hCG and saline water as control..Results The results suggested that Ovaprim and high dose of hCG treatment lead to shorter latency time (40 hours and 40 minutes), but ovulation percent, percentage of live embryos in the eyed stage and ovulation synchronization were lower than treated groups with Ovaprim alone or Ovaprim and low dose of hCG. Females from the control and hCG groups did not spawn..Conclusions The highest hormonal stimulation effectiveness was recorded in the group in which one hormonal substance (Ovaprim) was applied. Therefore the accurate ovulation time of snow trout, Schizothorax zarudnyi was difficult to be predicted..

Consistent high clinical pregnancy rates and low ovarian hyperstimulation syndrome rates in high-risk patients after GnRH agonist triggering and modified luteal support: a retrospective multicentre study

Are clinical pregnancy rates satisfactory and the incidence of OHSS low after GnRH agonist trigger and modified intensive luteal support in patients with a high risk of ovarian hyperstimulation syndrome (OHSS)? GnRH agonist trigger combined with 1500 IU hCG at the time of oocyte retrieval and subsequent estradiol and progesterone replacement in OHSS high-risk patients can facilitate fresh embryo transfer with high clinical pregnancy rates and a low risk of severe OHSS. Conventional luteal support packages are inadequate to facilitate a fresh transfer after a GnRH agonist trigger. A low dose of hCG (1500 IU) after oocyte aspiration can be used to replace the actions of early luteal LH to sustain implantation and the function of the early corpus luteum, although the level of risk of severe OHSS with this strategy is unclear. This international multicentre retrospective case study, including 275 women at high risk of OHSS, was undertaken during the period January 2011-December 2012. Women were identified as at high risk of OHSS, based on IVF response, ovarian reserve characteristics and previous history of having had treatment, in three clinical IVF centres in UK, Belgium and Australia. All three centres used a GnRH agonist trigger followed by one bolus of 1500 IU hCG 1h after oocyte retrieval. Moreover, the luteal phase was supported with daily vaginal progesterone and twice daily estradiol valerate. A total of 275 autologous cycles with fresh transfer were undertaken in a cohort of high-risk women as defined by baseline characteristics [median (interquartile range)]: age 31.6 (29-35) years, antral follicle count median 25 (18-34) and anti-Müllerian hormone median 49.1 pmol/l (35.2-69.3). At the end of stimulation, the peak estradiol median of 12 000 pmol/l (9400-15 914) and the mean oocyte yield of 17.8 ± 8.4 confirmed a high response. The overall clinical pregnancy rate was 41.8% per cycle started, with only two cases of severe OHSS reported (0.72%). No significant differences in clinical pregnancy rates between centres were identified. This is a retrospective study and future randomized controlled trials will be able to compare whether these outcomes can be improved upon by either segmentation of the stimulation cycle and embryo transfer or alternative aggressive luteal support strategies. In women who are undergoing ovarian stimulation and who develop an excessive ovarian response, the use of a GnRH agonist trigger combined with modified luteal support can provide the opportunity to proceed to fresh embryo transfer with adequate clinical pregnancy rates. However, this procedure will not completely eliminate the risk of OHSS and for women with an extreme ovarian response or with significant comorbidity, where the possibility of severe OHSS is unacceptable, we recommend GnRH agonist trigger followed by a freeze-all policy to completely avoid OHSS.

Serum insulin-like factor 3 is highly correlated with intratesticular testosterone in normal men with acute, experimental gonadotropin deficiency stimulated with low-dose human chorionic gonadotropin: a randomized, controlled trial

To study the potential role for using serum biomarkers, including insulin-like factor 3 (INSL3), 17α-hydroxyprogesterone, antimüllerian hormone, and inhibin B, as correlates of intratesticular T (IT-T) concentrations in men. Prospective, randomized, controlled trial. University-based medical center. Thirty-seven healthy men aged 18-50 years. All men received the GnRH antagonist acyline, plus very low doses of hCG (0 IU, 15 IU, 60 IU, or 125 IU) SC every other day or 7.5 g T gel daily (75 mg delivered). The IT-T concentrations obtained by percutaneous testicular aspiration with simultaneous serum protein and steroid concentrations were measured at baseline and after 10 days of treatment. Intratesticular and serum hormone and gonadotropin concentrations. After 10 days of gonadotropin suppression, serum INSL3 decreased by more than 90% and correlated highly with IT-T concentrations. In contrast, serum inhibin B, antimüllerian hormone, and 17α-hydroxyprogesterone did not correlate with IT-T. Serum INSL3 increased with the dose of hCG administered and returned to baseline after treatment. Serum INSL3 correlates highly with IT-T and serum T concentrations during acute gonadotropin suppression in men. Human chorionic gonadotropin stimulates dose-dependent increases in INSL3 and IT-T in healthy men and might be a useful biomarker of IT-T concentration in some clinical settings. NCT#00839319.

A randomized controlled dose–response pilot study of addition of hCG to recombinant FSH during controlled ovarian stimulation for in vitro fertilization

Is it possible to define an optimal dose of hCG in combination with rFSH from the first day of stimulation in the GnRH agonist protocol applied to IVF? Supplementation with hCG from the first day of stimulation may increase the number of top-quality embryos per patient. Daily doses of hCG up to 150 IU are compatible with good live birth rates. A ceiling level of estradiol (E(2)) was reached with hCG doses above 100 IU/day. A positive dose-response was seen for pre-ovulatory progesterone, but concentrations remained below values for which an impairment of endometrial receptivity has been previously reported. We suggest a large clinical trial to be proceeded with a group given 100 IU hCG daily versus a control group. Prospective multicentre studies have indicated increased live birth rates and increased number of top-quality embryos when low doses of hCG were associated with FSH. We analysed the clinical, embryological and endocrine aspects of adding increasing doses of hCG to rFSH from the first day of stimulation for IVF. A prospective randomized, controlled, open-label dose-response pilot study was conducted between February 2009 and June 2010 at Copenhagen University Hospital, Rigshospitalet, Denmark. Adequate allocation concealment was assured from sequentially numbered, opaque, sealed envelopes prepared from a computer-generated list. Scoring of the embryos was done in an assessor-blinded way. Endocrinologically normal IVF patients aged 25-37 years, BMI 18-30 kg/m(2), regular cycles and FSH <12 IU/l, were treated with a fixed dose of rFSH 150 IU/day and randomized to daily hCG dose of 0, 50, 100 or 150 IU from Day 1 of stimulation. Primary end-point was the total number of top-quality embryos on Day 3. Data were analysed by analysis of variance, Kruskal-Wallis test, chi-squared test or Poisson distribution count. A total of 62 patients were randomized into four hCG dose groups: Dose 0 (D0; n= 16), Dose 50 (D50; n= 15), Dose 100 (D100; n= 16) and Dose 150 (D150; n= 15). Two patients in D150 were withdrawn after randomization because of major (10- to 30-fold) hCG dosing errors, leaving 13 patients in this group. Thus, the results are based on the per protocol population. The mean numbers of top-quality embryos per patient were D0: 0.8 ± 1.2, D50: 0.5 ± 0.7, D100: 1.2 ± 1.7 and D150: 1.5 ± 1.7 (P= 0.04). All pregnancies were singleton gestations, and the live birth rates per started cycle were D0: 25%, D50: 27%, D100: 25% and D150: 31% (P= 0.98). Steady state level of serum (s)-hCG was reached on Day 6 of stimulation. S-hCG levels (IU/l) on the day of hCG administration were D0: <0.1, D50: 3.1 (2.6-3.6), D100: 5.5 (4.1-7.4) and D150: 11.0 (8.9-13.6) (P< 0.01). The patients receiving hCG supplementation were stratified by 33 and 66% percentiles into three groups according to the concentration of s-hCG on Day 6 of stimulation: 0.5-3.5 IU/l (n= 16), 3.5-8.0 IU/l (n= 14) and 8.0-21.1 IU/l (n= 14). The mean numbers of top-quality embryos in the three groups were 0.5 ± 0.9, 1.1 ± 1.8 and 1.5 ± 1.5, respectively (P= 0.03). The progesterone increments from stimulation Day 1 to the day of hCG triggering were D0 = 49%, D50 = 79%, D100 = 110% and D150 = 160% (P= 0.02). S-androstenedione level was highest in D150 (P< 0.01). S-E(2) was 2-fold higher in the D100 and D 150 compared with D0 (P= 0.09). BIAS, LIMITATION, GENERALISABILITY: Our study has a limited sample size. Supplementation with daily hCG dose up to 150 IU throughout stimulation has never been used before. Hence, this had to be tested in a small study before conducting a larger trial. Ferring Pharmaceuticals, Research and Development, provided funds for the endocrine measurements. CLINICALTRIAL.GOV REGISTRATION: NCT00844311.

Oocyte maturation employing a GnRH agonist in combination with low-dose hCG luteal rescue minimizes the severity of ovarian hyperstimulation syndrome while maintaining excellent pregnancy rates

The traditional hCG 'trigger' for initiating final oocyte maturation exacerbates ovarian hyperstimulation syndrome (OHSS) in patients with an excessive follicular response because of its sustained stimulatory effect on the corpora lutea. However, a GnRH agonist trigger can produce a short duration endogenous LH surge which is adequate to initiate oocyte maturation, but allows the corpora lutea to regress, reducing the severity of OHSS. This approach produces an excellent embryology outcome, but generally results in low pregnancy rates even with the early initiation of estrogen and progesterone luteal support. The purpose of this study was to determine if a low dose of hCG (1500 IU) support on the day of oocyte retrieval can maintain good pregnancy rates, while not abolishing the protective effect of an agonist trigger on the development of severe OHSS. This retrospective study included 71 women who were at high risk of severe OHSS (≥ 14 follicles ≥ 12 mm) and who received an agonist trigger for final oocyte maturation. The transfer of a solitary embryo produced a biochemical pregnancy rate of 60.6% and a clinical ongoing pregnancy rate of 52.1%. Only one patient was hospitalized with severe OHSS (1.4%), despite the average patient producing nearly 17 oocytes per cycle. Oocyte maturation employing a GnRH agonist (protocol) in combination with low-dose hCG luteal support produces excellent clinical pregnancy rates, while not compromising the ability of GnRH agonist to prevent severe OHSS.

Low-dose human chorionic gonadotropin versus estradiol/progesterone luteal phase support in gonadotropin-releasing hormone agonist–triggered assisted reproductive technique cycles: understanding a new approach

It remains unclear how GnRH agonist (GnRHa) triggering affects the luteal phase, so we investigated the luteal phase after GnRHa triggering, supported with conventional E(2)/P with or without low-dose hCG. E(2)/P support, compared with low-dose hCG, induced a shorter luteal phase (11.2 ± 1.1 vs. 15.0 ± 1.6 days) and fewer subjective complaints (0 vs. 42%), whereas hCG caused more free fluid accumulation and enlarged ovaries than E(2)/P alone. Steroids and low-dose hCG differentially affected corpus luteum function, ovarian size, free fluid accumulation, and patient comfort.

Dose-Dependent Increase in Intratesticular Testosterone by Very Low-Dose Human Chorionic Gonadotropin in Normal Men with Experimental Gonadotropin Deficiency

In men with infertility secondary to gonadotropin deficiency, treatment with relatively high dosages of human chorionic gonadotropin (hCG) stimulates intratesticular testosterone (IT-T) biosynthesis and spermatogenesis. Previously we found that lower dosages of hCG stimulated IT-T to normal. However, the minimal dose of hCG needed to stimulate IT-T and the dose-response relationship between very low doses of hCG and IT-T and serum testosterone in normal men is unknown. We induced experimental gonadotropin deficiency in 37 normal men with the GnRH antagonist acyline and randomized them to receive one of four low doses of hCG: 0, 15, 60, or 125 IU sc every other day or 7.5 g daily testosterone gel for 10 d. Testicular fluid was obtained by percutaneous aspiration for steroid measurements at baseline and after 10 d of treatment and correlated with contemporaneous serum hormone measurements. Median (25th, 75th percentile) baseline IT-T was 2508 nmol/liter (1753, 3502 nmol/liter). IT-T concentrations increased in a dose-dependent manner with very low-dosage hCG administration from 77 nmol/liter (40, 122 nmol/liter) to 923 nmol/liter (894, 1017 nmol/liter) in the 0- and 125-IU groups, respectively (P<0.001). Moreover, serum hCG was significantly correlated with both IT-T and serum testosterone (P<0.01). Doses of hCG far lower than those used clinically increase IT-T concentrations in a dose-dependent manner in normal men with experimental gonadotropin deficiency. Assessment of IT-T provides a valuable tool to investigate the hormonal regulation of spermatogenesis in man.

Oral contraceptive pretreatment in women undergoing controlled ovarian stimulation in ganirelix acetate cycles may, for a subset of patients, be associated with low serum luteinizing hormone levels, reduced ovarian response to gonadotropins, and early pregnancy loss

Oral contraceptive pretreatment facilitated scheduling of pure FSH/GnRH antagonist cycles but in a small subset of patients was associated with low serum LH levels, reduced ovarian response, and early pregnancy loss. Supplementation with LH could be examined as a possible way to improve cycle outcome.

Follicle-stimulating hormone enhances the development of preantral follicles in juvenile rats.

The stimulatory effects of gonadotropins on antral and preovulatory follicles are well known, but conflicting results have been reported regarding the gonadotropin responsiveness and dependency of preantral follicles. Taking advantage of the relatively uniform development of the first wave of follicles in the postnatal rat ovary, we evaluated the role of endogenous and exogenous gonadotropins on preantral follicle development. Reduction of the high levels of gonadotropins present in juvenile rats by either hypophysectomy (at Day 15) or GnRH antagonist treatment (starting from Day 11 of age) resulted in decreased ovarian weight at Day 19 of age that was associated with a reduced number of developing follicles and increased atresia of remaining follicles. In contrast, treatment with FSHctp (a long-acting FSH agonist) in intact (Days 5-19 of age), hypophysectomized (Days 15-19), or GnRH antagonist-treated (Days 11-19) animals resulted in increased ovarian weight and follicle development as determined histologically and by inhibin-alpha expression. A dose-dependent stimulatory effect of hCG on ovarian weight was seen when animals were cotreated with FSHctp and the GnRH antagonist. At low doses of hCG, augmentation of antral follicle formation occurred, whereas higher doses of hCG led to morphological signs of luteinization. These findings demonstrate the important role of endogenous gonadotropins in preantral follicle development and indicate that preantral follicles are highly responsive to exogenous gonadotropins.

Porcine follicle-stimulating hormone treatment of gilts during an altrenogest-synchronized follicular phase: effects on follicle growth, hormone secretion, ovulation, and fertilization.

Porcine FSH (SUPER OV), containing .03% LH activity, and equine chorionic gonadotropin (eCG) were administered during an altrenogest-synchronized follicular phase to determine their effects on follicle development, estrus, ovulation, and fertilization. Treatments were made by i.m. injection starting on d 1 (24 h after the last feeding of altrenogest): 1) saline, once, n = 14; 2) eCG (1,200 to 1,500 IU) once, n = 32; 3) FSH 14 (n = 2) or 21 (n = 6) NIH-FSH-S1 units/100 kg BW, divided among six injections at 12-h intervals (FSH14/21); 4) FSH, 28 NIH-FSH-S1 units/100 kg BW, divided among six injections at 12-h intervals, n = 12; and 5) FSH, 28 NIH-FSH-S1 units/100 kg BW and 100 IU hCG, two or six injections at 12-h intervals (FSH28+hCG), n = 13. Gilts were injected with 750 IU of hCG on d 5 to ensure ovulation. Twenty-eight eCG- and FSH-injected gilts (n = 6, 8, and 11 on treatments 3, 4, and 5, respectively) were bred and laparotomized on d 7 to recover ova and record ovulation rate. The mean number of ovulations and large (6- to 10-mm) follicles, respectively, on d 7 were as follows: saline (17, .7), eCG (43, .9), FSH14/21 (15, .6), FSH28 (12, 16), and FSH28+hCG (32, 21). Plasma FSH concentrations were at least threefold higher (P < .05) in gilts treated with FSH than in gilts not treated with FSH. The percentage in estrus was higher (P < .05) for saline- and eCG-treated gilts (100 and 87%, respectively) than for FSH-treated gilts (53%). Proportion of FSH28+hCG-treated gilts with fertilized ova (27%) was lower than for other groups (79 to 100%). In summary, the 3-d high dose FSH treatment (FSH28 and FSH28+hCG) during an altrenogest-synchronized follicular phase increased the number of potentially ovulatory follicles, but this potential benefit was not realized because many follicles failed to ovulate. The co-injection of low doses of hCG (FSH28+hCG) increased the ovulation rate and estradiol secretion but reduced ova recovery and fertilization rate compared with eCG and the other FSH treatments.

Assessment of luteal rescue and desensitization of macaque corpus luteum brought about by human chorionic gonadotrophin and deglycosylated human chorionic gonadotrophin treatment

The objective of the current study was to investigate the mechanism by which the corpus luteum (CL) of the monkey undergoes desensitization to luteinizing hormone following exposure to increasing concentration of human chorionic gonadotrophin (hCG) as it occurs in pregnancy. Female bonnet monkeys were injected (im) increasing doses of hCG or dghCG beginning from day 6 or 12 of the luteal phase for either 10 or 4 or 2 days. The day of oestrogen surge was considered as day ‘0’ of luteal phase. Luteal cells obtained from CL of these animals were incubated with hCG (2 and 200 pg/ml) or dbcAMP (2.5,25 and 100 M) for 3h at 37°C and progesterone secreted was estimated. Corpora lutea of normal cycling monkeys on day 10/16/22 of the luteal phase were used as controls. In addition thein vivo response to CG and deglycosylated hCG (dghCG) was assessed by determining serum steroid profiles following their administration. hCG (from 15–90 IU) but not dghCG (15-90 IU) treatment in vivo significantly (P < 0.05) elevated serum progesterone and oestradiol levels. Serum progesterone, however, could not be maintained at a elevated level by continuous treatment with hCG (from day 6–15), the progesterone level declining beyond day 13 of luteal phase. Administering low doses of hCG (15-90 IU/day) from day 6–9 or high doses (600 IU/day) on days 8 and 9 of the luteal phase resulted in significant increase (about 10-fold over corresponding control P < 0.005) in the ability of luteal cells to synthesize progesterone (incubated controls) in vitro. The luteal cells of the treated animals responded to dbcAMP (P < 0.05) but not to hCC added in vitro. The in vitro response of luteal cells to added hCG was inhibited by 0,50 and 100% if the animals were injected with low (15-90 IU) or medium (100 IU) between day 6–9 of luteal phase and high (600 IU on day 8 and 9 of luteal phase) doses of dghCG respectively; such treatment had no effect on responsivity of the cells to dbcAMP. The luteal cell responsiveness to dbcAMP in vitro was also blocked if hCG was administered for 10 days beginning day 6 of the luteal phase. Though short term hCG treatment during late luteal phase (from days 12—15) had no effect on luteal function, 10 day treatment beginning day 12 of luteal phase resulted in regain ofin vitro responsiveness to both hCG (P < 0.05) and dbcAMP (P < 0.05) suggesting that luteal rescue can occur even at this late stage. In conclusion, desensitization of the CL to hCG appears to be governed by the dose/period for which it is exposed to hCG/dghCG. That desensitization is due to receptor occupancy is brought out by the fact that (i) this can be achieved by giving a larger dose of hCG over a 2 day period instead of a lower dose of the hormone for a longer (4 to 10 days) period and (ii) the effect can largely be reproduced by using dghCG instead of hCG to block the receptor sites. It appears that to achieve desensitization to dbcAMP also it is necessary to expose the luteal cell to relatively high dose of hCG for more than 4 days

Effect of androgens on the germ cell-depleted testes of prenatally irradiated rats.

To study the effect of androgens on somatic testicular cells, rats were rendered germ cell depleted by prenatal irradiation (RX). Adult RX rats were treated with a desensitizing dose of a GnRH agonist (GnRHa; Zoladex), combined with an antiandrogen (Nilutamide) to preclude all androgen effects, or combined with testosterone or hCG to restore androgen action. The effect of these treatments for 3 weeks on the weight of testes and accessory sex glands, hormones (LH, FSH, testosterone, inhibin), testicular proteins, the pattern of incorporation of [35S]-methionine into testicular proteins (studied by two dimensional gel electrophoresis) and steady state mRNA levels for transferrin and androgen-binding protein (ABP) were evaluated. Combined treatment with GnRHa and antiandrogen virtually eliminated gonadotrophins, androgens and androgen effects. Testicular weight was reduced to 50% of that observed in RX controls. Treatment with GnRHa and testosterone resulted in supraphysiological levels of testosterone and testicular weights comparable to those observed in RX controls. FSH levels in these animals, however, were in the normal range. A low dose of hCG also restored testicular weight in the presence of low concentrations of serum testosterone and low normal levels of FSH. Neither polyacrylamide gel electrophoresis of total testicular proteins nor two dimensional gel electrophoresis of [35S]-methionine labelled proteins revealed striking changes in distinct testicular proteins as a result of androgen withdrawal or androgen treatment. Dot blot hybridization showed a three-fold increase in the mRNA level for ABP (expressed per microgram total RNA) in the Sertoli cell enriched testes of RX rats. This level was barely influenced by androgen withdrawal or androgen administration. The mRNA level for transferrin was increased six-fold in RX rats. A 50% reduction of this level was observed after combined treatment with GnRHa and antiandrogen. It is concluded that, in the germ cell-depleted testis, the major effect of androgens is an overall increase in protein and RNA synthesis rather than a very important and selective increase of a few gene products.

Folliculogenesis in hypophysectomized rats after treatment with recombinant human follicle-stimulating hormone.

To examine the role of FSH and LH in follicular growth and atresia, immature hypophysectomized (hypox) rats were treated twice daily for four days with a total dose either of 2.5 to 40 IU recombinant human FSH (recFSH; Org 32489) or of 8 IU recFSH supplemented with 0.2 to 5 IU hCG. RecFSH alone caused dose-dependent increases in ovarian weight and intraovarian estradiol (E2) but was unable to elevate circulating E2 levels. The number of antral follicles was also increased in a recFSH dose-dependent manner, and a gradual shift of small antral follicles to large preovulatory follicles was noted. The latter ovulated after a single bolus injection of 10 IU hCG. In comparison with follicles from hypox vehicle-treated animals, these follicles showed a diminished incidence of atresia, especially in the smallest size class of antral follicles. A total dose of > or = 10 IU recFSH increased uterine weight accompanied by endometrium proliferation. When 8 IU recFSH was supplemented with 0.2 to 5 IU hCG, ovarian weight was augmented in an hCG dose-dependent fashion, but no further increases in total number of antral follicles were noted except with the highest hCG dose given. Nevertheless, addition of relatively low doses of hCG caused considerable shifts of small follicles to large, preovulatory follicles. Furthermore, supplementation with hCG, especially low dosages of hCG (0.2 and 0.5 IU), reduced the incidence of atresia in antral follicles of all size classes. These data suggest that in the complete absence of LH activity, recFSH induces follicular growth up to the stage of mature preovulatory follicles and induces ovarian estradiol production and endometrium proliferation. The addition of small amounts of LH activity increases the percentage of healthy follicles.

Hormonal regulation of testicular human chorionic gonadotropin binding and steroidogenesis in adult mice with different forms of hereditary diabetes and obesity.

The regulation of testicular hCG binding and steroidogenesis in adult mutant mice with hereditary diabetes and obesity was studied. Low doses of hCG caused no change in hCG binding in obese (ob/ob) mice, whereas, in diabetic (db/db) mice, the increase in binding measured 24 h after hCG administration was not as great as in normal males. Intermediate doses of hCG caused a decrease in hCG binding in obese and normal mice, but not in diabetic animals. However, 72 h after injection of intermediate doses of hCG, a decrease in hCG binding also was observed in diabetic mice. Plasma testosterone was elevated 24 h after hCG injection in all types of mice studied, but the increase in diabetic mice was smaller than in normal animals. However, 72 h after treatment with hCG, plasma testosterone was still elevated in diabetic mice, but not in normal males. In vitro, hCG stimulated testicular testosterone synthesis in all groups of mice, but the observed increase was smaller in diabetic and obese than in normal animals. Plasma LH levels were higher in diabetic than in normal mice, whereas plasma FSH and prolactin levels were lower in obese mice than in normal animals. All parameters (i.e., LH receptors and circulating hormone levels) measured in yellow (Ay/a) mice were similar to those in normal (a/a) mice. The present study indicates that in these models for noninsulin-dependent diabetes, the testicular metabolism of LH receptors and capacity to secrete steroids is altered.

Changes in ovarian steroidogenesis in prepuberal rats induced to ovulate by low doses of human chorionic gonadotrophin.

To determine whether the decrease in ovarian 5 alpha-reduced androgen production before first ovulation might be caused by an increase in serum LH, prepuberal female rats were injected at 28-31 days of age with low doses of human chorionic gonadotrophin (hCG) (0.05-0.075 i.u., four times daily). This treatment resulted in ovulation of six to ten ova per rat on day 32 in all animals. Treatment with hCG resulted in a gradual decrease in ovarian content and production (i.e. content in ovary and medium after 4h of incubation) of 5 alpha-dihydrotestosterone (DHT) and 5 alpha-androstane-3 alpha, 17 beta-diol. The ovarian content of DHT and the production of 5 alpha-androstane-3 alpha, 17 beta-diol decreased within 24 h after the first injection of hCG. Oestradiol content and production increased between 24 and 48 h after the start of treatment and was maximal on day 31 (day of pro-oestrus). Activities of 5 alpha-reductase and aromatase were measured in ovarian homogenates obtained on days 29-31. Activity of 5 alpha-reductase in hCG-treated rats was lower than that in control rats on all days studied. Aromatase activity in hCG-treated rats increased between days 29 and 31. It was concluded that multiple injections of low doses of hCG, which may induce ovulation, cause a decrease in 5 alpha-reduced androgen production, which is probably due to a decrease in 5 alpha-reductase activity. The subsequent increase in oestradiol production corresponds with an increase in aromatase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Local regulation of Leydig cells by the seminiferous tubules. Effect of short-term cryptorchidism.

Unilateral cryptorchism was induced in adult rats for 24 h, and its effect on testicular morphology and intratesticular testosterone concentration after hCG-stimulation were studied. In seminiferous, tubules from abdominal testes an increased number of degenerating germ cells was noted in stages XIV-III of the spermatogenic cycle and Sertoli cells contained an increased amount of lipid droplets in stages XIV-VIII. However, germ cells and Sertoli cells from tubules at other stages of the cycle appeared unaffected. In scrotal testes the size of peritubular Leydig cells varied in phase with the spermatogenic cycle. The largest cells were found adjacent to stage VII-VIII and the smallest adjacent to stage XI-XII. In abdominal testes no stage-dependent variation in the size of peritubular Leydig cells was seen. Perivascular Leydig cells were of equal size in abdominal and scrotal testes. The testicular testosterone concentration following stimulation with a low dose of hCG was significantly lower in abdominal testes. It is suggested that the seminiferous tubules locally modulate Leydig cell function and that the stage specific stimulatory influence from stage VII-VIII is rapidly lost during experimental cryptorchidism.