Mean Serum Luteinizing Hormone Levels Research Articles

MO865SEX HORMONAL PROFILE OF PATIENTS ON MAINTENANCE HEMODIALYSIS AND CORRELATION WITH QUALITY OF LIFE AND DEPRESSION: A CROSS-SECTIONAL STUDY FROM SOUTH INDIA

Abstract Background and Aims Hormonal abnormalities in haemodialysis (HD) patients contribute to quality of life including sexual dysfunction. Whereas Short Form 36 (SF 36) questionnaire deals with the holistic assessment of the quality of life in patients, it is directly impacted by sexual dysfunction or erectile dysfunction in males. In this study we assessed the sex hormone levels in HD patients and its correlation with quality of life (QOL). Method In this single center cross-sectional study, 100 patients (50 males and 50 females) on maintenance HD for more than 6 months were included in the study. In female patients’ sex hormones that included Luteinizing Hormone (LH), Follicle Stimulating Hormone (FSH), Prolactin, Estrogen, Progesterone was assessed in midweek early morning blood sample. In male patients LH, FSH and Testosterone were assessed in midweek early morning samples. QOL assessment was done using SF 36 questionnaire. Results Mean age of our study populations was 33.76+/- 7.86 years with male female ratio of 1:1 and mean body mass index of 20.52 ± 2.89 kg/m2. Presumed chronic interstitial nephritis in was the most common cause of end-stage renal disease (76%) in our study followed by Diabetic Kidney disease (21%). In males, mean serum LH, FSH and Testosterone were 8.58 ± 3.56 mIU/ml, 8.9 ± 4.05, 217.46 ± 96.44 ng/dl respectively with 70% patients having testosterone deficiency. In females, mean serum LH, FSH, Prolactin, estrogen and Progesterone levels were 8.61± 3.86 mIU/ml, 8.08 ± 3.70 mIU/ml, 12.35 ± 5.70 ng/ml, 84.56 ± 27.39 pg/ml and 0.31 ± 0.22ng/ml respectively. Mean SF 36 score in our study was 55.37+/-12.22, in males 54.82+/-12.81 and in females 55.93+/-11.70. The prevalence depression was 53% (50% in males and 56% in females) in our study. There was no significant correlation between SF 36 scores and Beck depression inventory (BDI) scores with LH, FSH in both the genders. In males there was positive correlation between SF 36 scores and testosterone level (r= 0.366), and in females positive correlation between SF 36 score and progesterone level in women HD patients (r= 0.549) was seen. There was a negative correlation between BDI score and progesterone level in women (r=0. -510) and negative correlation between BDI score and testosterone in men (r= -0.371). Conclusion QOL as assessed by SF 36 in patients on HD is low. There was positive correlation between SF 36 scores and testosterone level in males and between SF 36 score and progesterone in females.

Preserved Ovarian Function Following Toxicity With Doxorubicin in Rats: Protective Effect of Nasturtium Officinale Extract

Background: Chemotherapy agents can cause ovarian dysfunction and eventually lead to infertility. This study investigated the effect of nasturtium officinale extract on the ovarian function following the toxicity induced by doxorubicin in female rats. Methods: Forty eight female Wistar rats (180-210g) were randomly divided in six groups as follows: Group I, normal rats receiving 1ml normal saline; Group II and III receiving 25 and 75 mg/kg of the extract daily by gavage for 21 days. Groups IV, V and VI receiving 10 mg/kg doxorubicin intraperitoneally on the first day. In addition, Group IV and V received 25 and 75 mg/kg of the extract, respectively. The serum levels of estrogen, progesterone, Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH) and ovarian Malondialdehyde (MDA) were determined after 21 days of treatment. The mean numbers of various graafian follicles and corpus lutea were recorded after treatment. Results: The mean serum FSH level in Group VI (0.11±0.01) significantly reduced compared to those in Groups II (0.21±0.05) and III (0.23±0.01), (P<0.05). The mean serum LH and estrogen levels in Group VI (0.16±0.08) reduced insignificantly compared to those in the controls (0.21±0.02), and in Groups II (0.23±0.03) and III (0.22±0.09). A significant reduction in the number of primary, secondary and graafian follicles were observed in Group VI compared to the control group (P<0.05). The serum MDA level significantly declined in Group V compared to that in Group VI (P<0.05). Conclusion: The nasturtium officinale extract attenuated the toxic effect of doxorubicin on the rat ovaries and protected the cell division in the follicles and the oocytes maturation.

Evidence of male hypogonadism at an early age as a familial risk of type 2 diabetes

ObjectivePrevious investigations provide evidence of an association of hypogonadism with type 2 diabetes in men, and low testosterone levels have been regarded a risk factor for the disease. Since a strong genetic predisposition to type 2 diabetes has been demonstrated, here we investigate a possible tendency towards hypogonadism in young male offspring of diabetic parents. Material and methodsThe study compares 32 male offspring of diabetic parents with 31 male offspring of nondiabetic parents matched by age. The subjects comprised boys (9–17years) and young adults (19–25years). Anthropomorphic measurements were made in all subjects. Fasting blood samples were analyzed for glucose and serum concentrations of testosterone (T), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), insulin and leptin were measured by ELISA. Free testosterone (FT) was calculated using T and SHBG levels. ResultsSerum T, FT and bioavailable T (BAT) levels in offspring of diabetic parents were significantly lower than those of offspring of nondiabetic parents across all age groups. Mean serum LH levels were also lower in offspring of diabetic parents compared to the controls. Although LH levels in young adults with diabetic parents, tended to be lower than those of age-matched controls but the difference was not statistically significant. Serum insulin and leptin, and insulin resistance measured by HOMA-IR were significantly raised in older offspring of diabetic parents but were within the normal range. ConclusionWhereas hypogonadism was the only indicator of a possible predisposition to metabolic dysfunction in peripubertal children of diabetic parents, a significant change in other metabolic markers becomes apparent at a more advanced age.

The impact of sexual activity on serum hormone levels after penile prosthesis implantation.

Penile prosthesis implantation is the final treatment option for patients who have erectile dysfunction. Most of the patients use their penile prosthesis successfully and frequently for penile-vaginal intercourse. Previous literature showed that decrease in sexual activity resulted in decreased serum testosterone levels and vice versa. The aim of this study was to examine the impact of sexual activity on serum sex hormone levels after penile prosthesis usage. In this study, we examined sixtyseven patients for their sex hormone changes who had penile prosthesis surgery 2.7 ± 1.5 years ago. Patients were using their penile prosthesis for sexual activity with a mean of 9.9 ± 5.7 times per month. Dehydroepiandrosterone sulfate was significantly higher compared to pre-surgery results (5.3 ± 2.6 vs 4.5 ± 2.9; p = 0.031). Mean serum total testosterone levels of patients before and after penile prosthesis usage were clinically significant 15.78 ± 4.8 nmol/L and 16.5 ± 6.1 nmol/L, respectively. Mean serum luteinizing hormone levels of patients before and after penile prosthesis usage were 3.98 ± 2.16 IU/L and 5.47 ± 4.76 IU/L, respectively. No statistical significance difference was observed in the mean total and free testosterone, estradiol and luteinizing hormone levels between pre- and post-surgery. This study results demonstrated that sexual activity changed sex hormone levels positively among those men who were implanted penile prosthesis because of erectile dysfunction.

Transdermal Androgen Therapy to Augment EPO in the Treatment of Anemia of Chronic Renal Disease

Hypogonadism and anemia are common comorbid conditions in dialysis patients. Testosterone replacement may improve such clinical parameters as anemia, sarcopenia, and low libido. Additionally, by increasing hemoglobin levels, testosterone replacement may allow for a dose reduction in recombinant human erythropoietin (rHuEPO), thereby reducing cost. This phase IV, single-center, placebo-controlled, double-blind study assessed the effect of transdermal testosterone on serum testosterone levels, rHuEPO dose required to maintain hemoglobin level, bone mineral content, lean body mass and fat content, cholesterol level, sexual function, and mood. Forty hypogonadal male hemodialysis patients who were administered rHuEPO were randomly assigned to 100 mg of topical 1% testosterone gel (Testim; Auxilium Pharmaceuticals, Norristown, PA) or placebo, applied daily for 6 months. Forty men with a mean age of 56 years and baseline serum testosterone level less than 300 ng/dL (< 10.4 nmol/L) participated in this trial. In men assigned to administration of transdermal testosterone, there was an increase beyond that in the placebo group in mean serum testosterone (77.1 ng/dL [2.7 nmol/L]), dihydrotestosterone (DHT; 0.8 nmol/L), and estradiol levels (6.3 pg/mL [23.0 pmol/L]) and a decrease in mean serum luteinizing hormone levels (-3.1 IU/L). Compared with subjects administered placebo, participants on testosterone replacement therapy did not show an appreciable change in rHuEPO dose (mean difference adjusted for baseline values, 12.6 U/kg/wk; P = 0.73), bone mineral density, lean body mass or fat content, cholesterol level, sexual function, or mood. Daily administration of 100 mg of topical 1% testosterone gel for 6 months failed to significantly increase serum testosterone or DHT levels in hypogonadal men with end-stage renal disease. Treatment with transdermal testosterone did not impact on rHuEPO requirement or clinical parameters in this small placebo-controlled study. Greater serum testosterone levels may be required to show clinical benefit in men with end-stage renal disease.

A short study in the treatment of hot flashes with buccal administration of 17-β estradiol

Objective: To assess the efficacy and safety of 17-β estradiol buccal tablets in reducing hot flush frequency (HFF) in postmenopausal women. Methods: Estradiol buccal tablets containing 0.05, 0.1, 0.2, or 0.4 mg or placebo were administered for 28 days to 99 postmenopausal women in a randomized, double-blind study; 19 premenopausal women were studied concurrently for comparison of laboratory data. Objective and subjective assessments of HFF were obtained along with measures of estradiol, estrone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). Results: Measurements of HFF revealed significant decreases from baseline in all estradiol groups ( P<0.01). In the 0.4 mg group, HFF decreased significantly compared to placebo ( P<0.01). All estradiol doses produced similar improvement in the vaginal maturation index. Mean serum estradiol levels increased as doses increased but were lower than in the premenopausal subjects. Mean serum FSH and LH levels decreased in all estradiol groups but not to the levels of the premenopausal subjects; the greatest decrease occurred at the two highest estradiol doses. Conclusion: A numerical dose–response relationship with hot flushes was seen in this pilot study comparing 0.05, 0.1, 0.2, and 0.4 mg buccal estradiol. Only 0.4 mg 17-β estradiol significantly reduced the occurrence of hot flushes compared to placebo.

Hormonal Characteristics in the Early Luteal Phase of Conceptive and Nonconceptive Menstrual Cycles

To determine whether serum hormone profiles are different in nonconceptive and conceptive menstrual cycles after ovulation and before implantation. Daily blood samples obtained during the luteal phase of nonconceptive cycles (n = 31) and conceptive cycles (n = 19) were analyzed (intersubject comparison). Samples obtained in sequential nonconceptive and conceptive cycles from five subjects (intrasubject comparisons) were analyzed to confirm results obtained with intersubject analysis. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E(2)), progesterone, and relaxin were measured by immunoassay. A cell-based bioassay was used to determine whether the measurement of serum immunoreactive LH is a result of cross-reaction with human chorionic gonadotropin (hCG). Intersubject analysis showed that mean serum LH levels were significantly higher in conceptive cycles on day 4 and day 5 after the FSH peak in urine, and this was confirmed by intrasubject analysis. The addition of antibodies that precipitate hCG did not affect the activity of LH receptor ligand molecules in serum samples collected during the early luteal phase of conceptive cycles, as measured by bioassay. In contrast, this LH receptor binding activity was completely removed when precipitating antibodies for LH were added. The mean levels of serum E(2) were higher in conceptive cycles after day 4 following the FSH peak in urine. The mean values of serum FSH, progesterone, and relaxin were not significantly different in nonconceptive and conceptive cycles during the same time interval. The differences in luteal phase hormones may reflect alterations in signaling in the hypothalamic-pituitary-ovarian axis that begin during the preovulatory period of nonconceptive cycles.

Cadmium affects the episodic luteinizing hormone secretion in male rats: possible age-dependent effects

Cadmium affects luteinizing hormone (LH) secretion through unknown mechanisms. The present study was undertaken to assess whether chronic exposure to low concentrations of cadmium may affect the episodic secretion of LH and if these effects are age-dependent. Male rats were given cadmium at a dose of 50 ppm in the drinking water, from day 30 to 60 or from day 60 to 90 of life. Age-matched rats with access to cadmium-free water were used as controls. At the end of the treatment, blood samples were collected every 7 min for 3 h, from 10:30 to 13.30 in conscious, freely moving rats. In control animals, mean serum LH levels and pulse duration increased with age ( P≤0.001), and pulse frequency and the relative amplitude of LH pulses decreased ( P≤0.001). Cadmium administration, from day 30 to 60 of life, decreased the pulse frequency and mean half-life of the hormone ( P≤0.05, P≤0.01, respectively). However, no changes in any other parameters studied were observed as compared to the control group. When cadmium was administered from day 60 to 90, mean serum LH levels and the duration of LH pulses decreased ( P≤0.05), whereas the pulse frequency increased ( P≤0.05). The absolute and relative amplitude of the LH peaks and the mean half-life of the hormone were not changed after cadmium administration from day 60 to 90. These results indicate that low doses of cadmium change the pulsatile secretion of LH in male rats and that the effect of cadmium on episodic LH release was age-dependent.

Direct Effects of Luteal Regression on Anterior Pituitary Response To GnRH

The preovulatory period of the ewe is marked by a dramatic decrease in concentrations of progesterone in serum during the late luteal phase, followed by elevated luteinizing hormone (LH) secretion, final follicular maturation and ovulation. This experiment was designed to ascertain the extent to which removal of endogenous progesterone negative feedback at the anterior pituitary gland, independent of effects at the hypothalamus, promotes increased secretion of LH in the hours immediately after induction of luteolysis. Estrus was synchronized in ovary-intact ewes with two injections of prostaglandin F 2α (PGF 2α) analog given 10 d apart (Day 0 = second day after the second PGF 2α injection). Ewes were subjected to hypothalamic-pituitary disconnection (HPD; n = 6) on Day 3 and were pulsed with gonadotropin-releasing hormone (GnRH). Ewes were used during the estrous cycle or received approximately 400 IU pregnant mare serum gonadotropin (PMSG) on Day 2 to stimulate ovulation; there was no difference (P < 0.10) in ovulation rate or progesterone production between these two groups. Luteal regression was induced by injection of PGF 2α analog on approximately Day 10 of the estrous cycle. Blood samples were collected around exogenous GnRH pulses before and at 2- or 4-hr intervals after PGF 2α administration and concentrations of LH and progesterone determined. At 4, 12 and 24 hr after PGF 2α administration, mean serum progesterone levels in all ewes had decreased by 54.7%, 66.2% and 89.4%, respectively (P < 0.05) from pre-injection levels. The decrease in progesterone was associated with an increase (P < 0.01) in LH pulse amplitude with means at 4-hr post-PGF 2α ranging from 190% to 288% of pre-PGF 2α values. Mean serum LH levels were also increased (P < 0.01) within 4 hr of PGF 2α administration and remained elevated at all but the 24-hr time point. The timing of this increase (within 4 hr) indicates that it is independent of changes in serum estradiol concentrations, which do not increase for at least 16 hr after induction of luteolysis. Thus, removal of endogenous progesterone negative feedback at the anterior pituitary gland in the hours immediately after induction of luteolysis seems to play a role in facilitating LH release independently of hypothalamic action.

Acute ethanol administration in diestrus-2 in the rat on pulsatile prolactin and LH release

Exposure to ethanol is followed by changes in reproductive function in man and animals, characterized by modifications in the secretion patterns of prolactin and luteinizing hormone (LH). As both hormones are secreted in an episodic fashion, the present work was undertaken to study the effects of acute ethanol administration on pulsatile prolactin and LH secretion patterns in adult female rats. Rats were previously cannulated to allow a continous blood withdrawal to study the pulsatile patterns of prolactin and LH. The mean values of prolactin during the bleeding period and the absolute pulse amplitude of prolactin peaks were significantly increased by acute ethanol administration, whereas a significant decrease of relative pulse amplitude and frequency of this hormone was observed. On the other hand, ethanol administration increased the mean serum LH levels and the absolute and relative amplitudes of LH peaks. Ethanol treatment did not modify either frequency or duration of LH peaks. These data suggest that acute ethanol administration in adult female rats is followed by changes in the pulsatile prolactin and LH secretory patterns, which might be part of the mechanism to explain ethanol effects on the endocrine system.

Daytime variations of serum testosterone and luteinizing hormone in captive thick-tailed bush babies (Galago garnetti)

Mean daytime serum levels of testosterone (T) and luteinizing hormone (LH) were determined in eight male thick-tailed bush babies at different times of the day by radioimmunoassay and leydig cell bioassay respectively. Blood samples were obtained twice a week from each animal at different times of the day between 08:30 and 16:00. This was carried out for a period of eight weeks. There was significantly higher mean serum T levels in the morning compared to evening hours (p<0.05). There was no significant variation in mean serum LH levels, and no significant correlation between serum T and LH levels.

Endocrinology: The combination of gonadotrophin-releasing hormone (GnRH) antagonist and pulsatile GnRH normalizes luteinizing hormone secretion in polycystic ovarian disease but fails to induce follicular maturation

To evaluate the role of altered luteinizing hormone (LH) release in the mechanism of polycystic ovarian disease (PCOD) anovulation, we have co-administered a gonadotrophin-releasing hormone (GnRH) antagonist and pulsatile GnRH therapy to two clomiphene citrate-resistant PCOD patients. The aim was to correct their inappropriate gonadotrophin secretion. Nal-Glu was administered s.c. every 72 h to both subjects for 3 weeks. On day 7 after commencing the study, intravenous pulsatile GnRH therapy was initiated (10 micrograms/pulse) every 90 min for 15 days to both subjects. In one subject, Nal-Glu treatment was continued and the GnRH dose was increased to 20 micrograms/pulse for 10 additional days. Prior to Nal-Glu, mean serum LH levels were 10.4 +/- 1.6 and 9.3 +/- 1.3 mIU/ml (mean +/- SEM) and mean interpulse intervals were 67.1 and 60 min in patients 1 and 2, respectively. Mean serum FSH levels were 4.9 +/- 0.4 and 4.2 +/- 0.2 mIU/ml for patients 1 and 2, respectively. LH pulsatility was abolished following Nal-Glu, mean serum LH decreased to 1.1 +/- 0.1 and 1.3 +/- 0.5 mIU/ml and mean FSH to 1.8 +/- 0.1 and 2 +/- 0.1 mIU/ml in the two subjects. On the 4th day of the combined therapy, mean serum LH increased to 5.4 +/- 1.3 and 3.9 +/- 0.9 mIU/ml with a mean interpulse interval of 72 and 80 min, respectively. Mean FSH levels increased to 3 +/- 0.1 and 2.8 +/- 0.1 mIU/ml, respectively and to 5.5 +/- 0.2 mIU/ml after the GnRH dose was increased in patient 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulsatile luteinizing hormone secretion during the first and the fourth cycle on two different oral contraceptives containing gestodene.

Oral contraceptives inhibit ovarian follicular growth by suppressing the release of gonadotropins from the pituitary. We studied basal and gonadotropin-releasing hormone-stimulated gonadotropin release, as well as pulsatile luteinizing hormone (LH) secretion, in ten healthy volunteers who had not used oral contraceptives before. Subjects received either a monophasic preparation containing 30 micrograms of ethinylestradiol and 75 micrograms of gestodene (group 1) or a triphasic formulation containing 30-40 micrograms of ethinylestradiol and 50, 70 and 100 micrograms of gestodene (group 2). Blood sampling at 10-min intervals during 6-h periods was performed on days 1, 8, 15 and 21 of both the first and fourth pill cycle. Thirteen healthy volunteers with regular ovulatory cycles served as normal controls. Both LH and follicle-stimulating hormone (FSH) were measured by a sensitive immunoradiometric assay. Pulsatile LH secretion was observed in all oral contraceptive users. Mean serum LH and FSH levels, number of pulses/6 h and the amplitude of LH pulses on day 1 in both the first and fourth pill cycle did not differ from early follicular phase controls in both groups. The FSH levels were suppressed rapidly in both groups, even in first cycles, while LH serum levels progressively declined in all cycles studied. In both groups, amplitudes of LH pulses decreased from day 8 onwards, with a substantial number of low-amplitude pulses (< 0.75 U/l) interspersed between large-amplitude pulses. On day 1 of the fourth pill cycle a significant number of pulses were of low amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Casodex on Sleep-Related Erections in Patients with Advanced Prostate Cancer

Sleep-related erections in 5 patients with stage T3N0M0 prostate cancer treated with a new nonsteroidal antiandrogen, Casodex, were evaluated with continuous monitoring of penile tumescence and rigidity on multiple nights. Mean serum luteinizing hormone levels were 7.2 ± 1.2 IU/1. before therapy and increased to 14 ± 3.6 IU/l. after 6 months of therapy. Serum testosterone and estradiol levels also increased from a basal level of 5.05 ± 1.9ng./ml. and 102 ± 18 pmol./l., respectively, to 8.04 ± 1.32ng./ml. and 175 ± 20 pmol./l., respectively, after 6 months of therapy. No significant modifications in regard to number of nocturnal penile tumescence episodes, maximum penile circumference and total rigidity time were found before and after therapy. Only 1 patient reported a decrease in sexual drive and libido. All patients presented with stable disease (National Prostatic Cancer Treatment Group criteria) and an unmodified performance status (Eastern Cooperative Oncology Group) after 6 months. Pure antiandrogen therapy did not seem to interfere significantly with the erectile capability of men with prostate cancer.

Effect of bleeding stress and variable suckling intensity upon serum luteinizing hormone in Brangus heifers

In the first experiment, the effect of the stress of blood collection (via tail vessel puncture) on serum luteinizing hormone (LH) was evaluated in six nonsuckled first calf Brangus heifers. The animals were bled on days 22 and 31 postpartum at 15 minute intervals for a period of two hours. Blood was processed to yield serum and analyzed for LH via radioimmunoassay (RIA). There were no significant differences or fluctuations in serum LH levels between bleeding periods or between cows. Serum LH concentrations in nonsuckled cows were not affected by the stress of blood collection. In the second experiment, 24 first calf Brangus heifers were randomly assigned to one of four treatment groups. Treatment 1 cows were suckled once daily for approximately 30 min starting day 21 postpartum. Treatment 2 cows were suckled twice daily for approximately 30 min each time, starting 21 days postpartum. Treatment 3 cows were suckled once daily for approximately 30 min starting 30 days postpartum. Treatment 4 cows were suckled twice daily for approximately 30 min each time starting 30 days postpartum. Each cow was bled via tail vessel puncture on days one and nine following the start of each treatment. The blood sampling regime was similar to that used in Experiment 1 and consisted of four presuckling samples taken at 15 min intervals, one midsuckling sample (the calf was allowed to suckle for 15 min) and four postsuckling samples taken at 15 min intervals. Blood was collected, processed to yield serum and assayed for LH via RIA. Suckling intensity (SI) was found to have a significant effect on serum LH levels. The once daily suckled cows had higher (P<.01) mean serum LH levels than did the twice daily suckled cows (1.70 ± .03 and 1.53 ± .03 ng/ml, respectively). The LH concentrations decreased (P<.01) from the first to last bleeding time (BT). The mean serum LH levels for the presuckling, midsuckling and the first postsuckling samples were higher (P<.05) than the last postsuckling sample. The mean serum LH level for the first time period prior to suckling was higher (P<.05) than the last postsuckling sample. The mean serum LH level for the first time period prior to suckling was higher (P<.05) than the last two periods after suckling (1.73 ± .08 ng/ml vs 1.51 ± .06 and 1.41 ± .06 ng/ml). Bleeding day (BD) and weaning day (WD) did not alter serum LH levels. The interactions found to be significant (P<.01) were SI×BD, SI×WD, BD×WD and BT×SI×BD×WD.

Reproductive studies of Brahman cattle II. Luteinizing hormone patterns in ovariectomized Brahman and Hereford cows before and after injection of gonadotropin releasing hormone

Six Brahman and six Hereford long-term ovariectomized cows were bled via tail vessel at 15 minute intervals for a period of 4 hours. Serum was collected and analyzed via radioimmunoassay (RIA) for luteinizing hormone (LH) to determine if ovariectomized Brahman and Hereford cows have pulsatile LH patterns and if breed of animal influenced LH patterns. Brahman and Hereford ovariectomized cattle did have pulsatile LH patterns. Although the trend was for higher LH levels in Hereford than Brahman cows there were no significant differences in mean serum LH levels, number or magnitude of LH peaks or serum LH pulse height. Six Brahman and five Hereford long-term ovariectomized cows were injected (IM) with a single dose of 500μg of gonadotropin releasing hormone (GnRH). Animals were bled via tail vessel at 15 minute intervals for a period of 6 hours. Serum was assayed for LH via RIA to determine if ovariectomized Brahman and Hereford cows differ in GnRH induced LH response. All animals showed increased serum LH in response to GnRH injection within the first 15 minute collection interval. There were no significant differences in duration of response between ovariectomized Brahman or Hereford cows. Ovariectomized Brahman cows had significantly lower (P<.005) Lh values per period than ovariectomized Hereford cows. It was therefore concluded that ovariectomized Brahman cows were significantly less responsive to GnRH induced LH release than were ovariectomized Hereford cows, although duration and shape of the response curves were not different.

The in-vitro and in-vivo effects of diethylstilbestrol on testicular synthesis of testosterone

The effect of diethylstilbestrol (DES) on the percent conversion of a 14C-progesterone ( 14C-P) substrate to 14C-testosterone ( 14C-T) when added to incubates of rat testicular homogenates has been measured. Similarly the effect of DES administered parenterally to intact adult rats at 9 dose regimens on such conversion has been evaluated. In addition, in the latter group serum luteinizing hormone (LH) levels were assessed simultaneously. DES added in-vitro significantly reduced T formation at every level. Only the large parenteral dose of DES affected T synthesis after 24 hours, while every parenteral dose significantly reduced T synthesis with 4 and 8 day regimens. Mean serum LH levels failed to reflect a significant decrease at the 1 and 4 day dose level, but did decrease significantly in 2 of 3 groups on the 8 day regimen. These results suggest that there is a direct effect of DES at a testicular level inhibiting T synthesis not associated with a simultaneous drop in mean serum LH levels. A measurable decrease in LH concentration does occur with continued treatment.

Serum luteinizing hormone by radioimmunoassay in normal children

Using a sensitive radioimmunoassay, serum luteinizing hormone (LH) levels have been determined in 249 normal children (5 to 18 years of age), 30 normal adult males, 2 normal adult females throughout a menstrual cycle, and 19 patients with pituitary deficiency. The mean levels in prepubertal boys and girls were comparable (3.4 and 2.8 m.I.U. per milliliter, respectively) and began increasing at the same age (10 to 12 years) in both sexes. An increase in serum LH was noted in the males but not in the females before beginning sexual maturation was apparent clinically. In adult males and females, the mean serum LH levels (10.9 and 10.2 m.I.U. per milliliter, respectively) were approximately 3.5 times prepubertal values. Patients with pituitary deficiency had a very low mean level (1.7 m.I.U. per mililiter), but some immunochemical LH was found in all sera. In males, the urinary excretion of 17-ketosteroids had a statistically significant correlation (correlation coefficient=0.73) with the serum LH leterminations.