Low Follicle-stimulating Hormone Concentrations Research Articles

Time-varying associations of gestational and childhood triclosan with pubertal and adrenarchal outcomes in early adolescence.

Triclosan is an endocrine-disrupting chemical, but associations with pubertal outcomes remain unclear. We examined associations of gestational and childhood triclosan with adolescent hormone concentrations and pubertal stage. We quantified urinary triclosan concentrations twice during pregnancy and seven times between birth and 12 years in participants recruited from Cincinnati, OH (2003-2006). We averaged concentrations across pregnancy and childhood and separately considered individual exposure periods in multiple informant models. At 12 years, we measured serum hormone concentrations (males [n = 72] and females [n = 84]-dehydroepiandrosterone-sulfate, luteinizing hormone, follicle-stimulating hormone; males-testosterone; females-estradiol). Also at age 12 years, participants self-reported physical development and menarchal timing. We estimated associations (95% confidence interval) of triclosan with hormone concentrations, more advanced physical development, and age at menarche. For females, each doubling of childhood triclosan was associated with 16% lower estradiol concentrations (-29%, 0%), with stronger associations for measures closer to adolescence. We found suggestive evidence that higher triclosan at any age was associated with ~10% (for gestational triclosan: -18%, -2%) lower follicle-stimulating hormone concentrations among males and early postnatal (1-3 years) triclosan was associated with 63% (5%, 96%) lower odds of advanced pubic hair development in females. In multiple informant models, each doubling of gestational triclosan concentrations was associated with 5% (0%, 9%) earlier age at menarche, equivalent to 5.5 months. Gestational and childhood triclosan concentrations were related to some pubertal outcomes including hormone concentrations and age at menarche. Our findings highlight the relevance of elucidating potential sex-specific and time-dependent actions of triclosan.

Effects of KISS1 structural polymorphism on the risk of polycystic ovary syndrome and reproductive hormones in Iraqi women who take metformin.

To identify the effects of metformin and kisspeptin structural polymorphism on the risk of polycystic ovary syndrome (PCOS) in Iraqi women. Samples were collected at the family planning center of Al-Hassan Teaching Hospital (infertility clinic), Iraq. Hormonal and hematological parameters were measured. Kisspeptin structural polymorphisms were analyzed by polymerase chain reaction using a conventional thermal cycler and Phyre2 predictions. Kisspeptin concentrations were assessed by an enzyme-linked immunosorbent assay. Follicle-stimulating hormone (FSH) was the only sex hormone that changed in women with PCOS after metformin treatment. FSH concentrations were significantly increased after therapy compared with before therapy (9.39 ± 2.1 vs 5.13 ± 1.53 IU/L). We found that a single nucleotide polymorphism substituting G to C was related to PCOS. The kisspeptin structural polymorphism showed that the C allele was related to low FSH concentrations after treatment (6.92 ± 2.2 IU/L to 5.34 ± 1.58 IU/L). Kisspeptin concentrations were significantly lower after metformin treatment than before metformin treatment (395.44 ± 67.83 vs 273.18 ± 42.98 ng/mL). A variation in the KISS1 gene or its protein structure may be involved in the development of PCOS. The response to metformin may be used as an indicator and could contribute to the early diagnosis and medical therapy of PCOS.

The role of gonadotropin-releasing hormone neurons in polycystic ovary syndrome.

Given the critical central role of gonadotropin‐releasing hormone (GnRH) neurons in fertility, it is not surprising that the GnRH neural network is implicated in the pathology of polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility. Although many symptoms of PCOS relate most proximately to ovarian dysfunction, the central reproductive neuroendocrine system ultimately drives ovarian function through its regulation of anterior pituitary gonadotropin release. The typical cyclical changes in frequency of GnRH release are often absent in women with PCOS, resulting in a persistent high‐frequency drive promoting gonadotropin changes (i.e., relatively high luteinizing hormone and relatively low follicle‐stimulating hormone concentrations) that contribute to ovarian hyperandrogenemia and ovulatory dysfunction. However, the specific mechanisms underpinning GnRH neuron dysfunction in PCOS remain unclear. Here, we summarize several preclinical and clinical studies that explore the causes of aberrant GnRH secretion in PCOS and the role of disordered GnRH secretion in PCOS pathophysiology.

FSH promotes fat accumulation by activating PPARγ signaling in surgically castrated, but not immunocastrated, male pigs

Follicle-stimulating hormone (FSH) was recently implicated as a novel regulator of fat accumulation. Surgical castration causes high FSH concentrations and increases fat accumulation, whereas immunocastration results in low FSH concentrations and less fat in immunocastrated boars versus barrows. However, detailed information regarding the role of FSH in regulation of fat accumulation in male pigs is unclear. First, expression of FSH receptor was confirmed (real-time quantitative PCR) in subcutaneous and visceral adipose tissues (SAT and VAT, respectively) of boars. Then, surgical castration (high FSH model) was compared to immunocastration (low FSH model) to investigate potential roles of FSH in adipogenesis and fat accumulation. High FSH concentrations after surgical castration activated PPARγ signaling by upregulating expression of CREB (P < 0.05), and then recruited an array of PPARγ target adipogenic genes, including transcription factor (C/EBPα), long-chain fatty acid uptake (LPL), fatty acid de novo synthesis (FASN, ACACA) and lipid droplet formation (PLIN1) in both SAT and VAT, promoting fat accumulation in barrows. In contrast, much lower serum FSH concentrations in immunocastrates attenuated (P < 0.05) expressions of PPARγ and PPARγ target genes in both SAT and VAT, resulting in less fat accumulation in immunocastrated boars versus barrows. We concluded that the substantially elevated FSH concentrations in barrows promoted fat accumulation by activating the PPARγ signaling pathway in adipose tissues, whereas immunocastrates accumulated less fat due to low FSH.

Gonadotropins and Their Association with the Risk of Prediabetes and Type 2 Diabetes in Middle-Aged Postmenopausal Women.

Recent studies have suggested that a low concentration of follicle-stimulating hormone (FSH) is associated with a higher prevalence of metabolic disturbances in postmenopausal women. In this study, we aim to evaluate the association between FSH, luteinizing hormone (LH), and LH/FSH ratio values and the risk of insulin resistance (HOMA-IR >2.0), prediabetes (IFG), and type 2 diabetes in a 5-year prospective study in postmenopausal women. 114 postmenopausal women were divided into 4 groups: group 1 (baseline and follow-up normoglycemic women), group 2 (normoglycemic women at baseline progressing to IFG), group 3 (women with baseline and follow-up IFG), and group 4 (women with baseline IFG progressing to diabetes). Baseline and follow-up anthropometric measurements and blood collections were performed. Serum/plasma was assayed for glucose, HDL-C, TG, C-reactive protein (CRP), 17beta-estradiol, estrone, insulin, thyroid-stimulating hormone (TSH), FSH, and LH. Homeostatic model assessment of insulin resistance (HOMA-IR) and LH/FSH ratios were calculated. The baseline concentrations of FSH and LH statistically decreased across all four groups (the highest concentrations in group 1 and the lowest in group 4; p < 0.001). A logistic regression analysis showed that a 1 SD decrease in the z-score of FSH concentration is associated with a threefold increased risk of IFG and a fivefold increased risk of HOMA-IR of >2.0 and diabetes. The LH concentration had odds ratio (OR) values about two times lower than the FSH concentration. The ORs of the LH/FSH ratio were only significant for IFG. In conclusion, FSH concentration is strongly associated with insulin resistance, prediabetes, and diabetes in postmenopausal women with normal or impaired fasting glucose. LH and the LH/FSH ratio are also related to metabolic disturbances after menopause, yet to a lesser extent.

Gonadal hormones level and morphometric traits in cow deliveres twin and single calves

The objectives of study were to investigate follicle stimulating hormone (FSH) and luteinizing hormone (LH) level in four groups beef cow composed of Ongole Grade cow delivered twinning calves (OGT), Ongole Grade cow delivered single calf (OGS), Simmental crossbred cow delivered twinning calves (SCT) and Simmental crossbred cow delivered single calf (SCS). Morphometric traits included body weight, heart girth, body length, shoulder height, and abdominal circumference were taken from cows. Cows were reared by farmers in Grobogan and Kendal Regency, Central Java. Blood serums of cows were taken at estrus. FSH and LH concentration were measured with enzyme linked fluorescent assays (ELFA) technique.FSH and LH concentration were compared between OGT, OGS, SCT, and SCS. Result showed that there were no significant difference of FSH and LH concentration between OGT and OGS, between OGT and SCT, between OGT and SCS. There were no significant difference between OGS and SCT, and OGS and SCS. There were no significant difference between SCT and SCS. Low concentration of FSH and LH in all cows was related to suckle period, when prolactin concentration was inversely related to FSH and LH concentration.

Pharmacogenetics of follicle-stimulating hormone action

To review the current knowledge of genetic variants in the two genes affecting the individual responsiveness to follicle-stimulating hormone (FSH) action-the FSH beta-subunit (FSHB) and the FSH receptor (FSHR), as well as the pharmacogenetic ramifications of the findings. Four common variants in the FSHB and the FSHR genes were shown to exhibit significant effect on FSH action: linked FSHR variants Thr307Ala and Asn680Ser determining common receptor isoforms, and gene expression affecting polymorphisms FSHR -29G/A and FSHB -211G/T. In women, the FSHR Thr307Ala/Asn680Ser polymorphisms show consistent predictive value for estimating the most optimal recombinant FSH dosage in controlled ovarian hyperstimulation (COH). The same variants exhibit a potential for the pharmacogenetic assessment of the treatment of polycystic ovarian syndrome. The FSHR -29G/A variant was also shown to contribute to ovarian response to COH. Pilot studies have suggested the FSHB -211 TT homozygous oligozoospermic men with genetically determined low concentration of FSH, as potentially the best responders to FSH treatment; furthermore, modulation of this response by FSHR polymorphisms is possible. Genetic variants in FSHB and FSHR exhibit a potential for pharmacogenetic applications in selecting appropriate treatment options (timing and dosage) in male and female conditions requiring or benefiting from FSH therapy.

Predictive Factors of Successful Varicocelectomy in Infertile Patients

Aim: To examine the predictive factors of successful varicocelectomy in infertile patients. Methods: Thirty-five infertile male patients with varicocele and requiring varicocelectomy were recruited in this study. The patients were divided into 2 groups based on their recovery outcome after subinguinal microsurgical varicocelectomy. Patients who showed significant improvement on their sperm density, motility and morphology 6 months after varicocelectomy were designated as group 1, whereas those who showed no improvement 6 months after surgery were designated as group 2. The predictive factors that were examined included: age; preoperative semen quality (i.e. sperm density, motility and morphology); testicular volume; seminal volume; varicocele grade; the number of ligated veins; body mass index (BMI), and serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, testosterone, alkaline phosphatase (Alk-p), lactic dehydrogenase (LDH), cholesterol and triglyceride. Results: Sperm density, motility and morphology improved significantly 6 months after varicocelectomy in group 1 patients (n = 35; 71.4%). Group 1 patients had significantly higher testicular volumes (mean ± SD: 29.6 ± 5.9 vs. 23.2 ± 6.1 ml), lower FSH (11.3 ± 2.9 vs. 16.1 ± 4.8 mIU/ml) and higher numbers of ligated veins (9.3 ± 0.8 vs. 7.9 ± 0.7) than group 2 patients. No significant association was observed between surgical outcome and age, preoperative sperm density, motility and morphology, seminal volume, varicocele grade, BMI and serum levels of LH, prolactin, testosterone, Alk-p, LDH, cholesterol and triglyceride. Conclusions: These findings suggest that the significant predictive factors of successful varicocelectomy in infertile patients were high testicular volume (>29.6 ml), low serum concentration of FSH (<11.3 mIU/ml) and high number of ligated veins (>9).

Activin promotes follicular integrity and oogenesis in cultured pre-antral bovine follicles

The aim of this study was to determine the individual and combined effect of activin and follicle stimulating hormone (FSH) on somatic and germ cell development in cultured pre-antral follicles. Pre-antral bovine follicles (mean diameter 157 +/- 3, range 132-199 microm) were cultured for 8 days in serum-free medium in the presence of either 100 ng/ml of recombinant human activin A (rhAct A), 100 ng/ml rhAct A combined with a high (100 ng/ml) or low (50 ng/ml) concentration of recombinant FSH (rFSH) or 50 ng/ml rFSH alone. Intrafollicular connexin 43 expression and actin-based cell adhesion were assessed on Day 2 and 4 of culture. Steroidogenesis was evaluated after Day 4 and 8. Follicles exposed to 100 ng/ml activin maintained expression of connexin 43 at the follicular periphery. In the presence of activin, with or without 100 ng/ml or 50 ng/ml FSH, follicles were steroidogenic undergoing significant growth (P < 0.01), granulosa cell proliferation (P < 0.01) and antral cavity formation (P < 0.05) compared with cultured controls. Maximum oocyte growth occurred in the presence of 100 ng/ml activin alone with a significant percentage of these oocytes maintaining normal morphology over controls (P < 0.05). These results are consistent with a role for activin in maintaining oocyte granulosa cell interactions due to increased peripheral granulosa cell adhesion to the basement membrane and retention of adhesion at the surface of the zona pellucida. Thus, the polarized expression of cell contact interactions promoted by activin supports ongoing folliculogenesis.

Testosterone Concentration in Young Patients With Diabetes

OBJECTIVE—We have previously shown that hypogonadotrophic hypogonadism is common in middle-aged patients with type 2, but not with type 1, diabetes. We have now investigated the total and free testosterone concentrations in young (aged 18–35 years) type 1 and type 2 diabetic patients.RESEARCH DESIGN AND METHODS—In this study carried out in a tertiary referral center, serum concentrations of total and free testosterone were measured in 38 type 1 diabetic (mean age 26.45 ± 0.89 years) and 24 type 2 diabetic (mean age 27.87 ± 0.97 years) subjects. The mean BMI of type 1 and type 2 diabetic patients was 27.41 ± 1.18 and 38.55 ± 2.04 kg/m2, respectively (P < 0.001).RESULTS—The mean total testosterone concentration of type 1 and type 2 diabetic patients was 22.89 ± 1.23 and 11.14 ± 0.99 nmol/l, respectively (P < 0.001). The mean free testosterone concentration of type 1 and type 2 diabetic patients was 0.489 ± 0.030 and 0.296 ± 0.022 nmol/l, respectively (P < 0.001). Eight of 24 (33%) type 2 diabetic patients had subnormal free testosterone concentrations (<0.225 nmol/l). Using an age-based reference range, 14 of 24 (58%) type 2 diabetic patients had low free testosterone concentrations (<0.278 nmol/l). Three of 38 (8%) type 1 diabetic patients had free testosterone concentrations below the lower limit of normal (P = 0.02 when compared with type 2 diabetes). Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations in type 2 diabetic patients with low free testosterone concentrations were in the normal range and were similar to those in type 1 diabetic patients.CONCLUSIONS—Young type 2 diabetic patients have significantly lower plasma concentrations of total and free testosterone and inappropriately low LH and FSH concentrations with a very high prevalence of hypogonadotrophic hypogonadism, when compared with type 1 diabetic patients of a comparable age. The potential implications for their sexual and reproductive function during prime reproductive years are profound.

Laminin-alpha6beta1 integrin interaction enhances survival and proliferation and modulates steroidogenesis of ovine granulosa cells.

This study aimed to determine the physiological role of laminin (LN) and its receptor, alpha(6)beta(1) integrin, in controlling the functions of granulosa cells (GC) during follicular development in sheep ovary. Immunohistochemistry experiments showed the presence of increasing levels of LN (P<0.0001), and high levels of mature alpha(6)beta(1) integrin in GC layers of healthy antral follicles during the follicular and the preovulatory phases of the estrous cycle. In vitro, the addition of a function-blocking antibody raised against alpha(6) subunit (anti-alpha(6) IgG) to the medium of ovine GC cultured on LN impaired cell spreading (P<0.0001), decreased the proliferation rate (P<0.05) and increased the apoptosis rate (P<0.05). Furthermore, addition of anti-alpha(6) IgG enhanced estradiol (E2) secretion by GC in the presence or absence of follicle-stimulating hormone (FSH), luteinizing hormone or insulin-like growth factor-I in culture medium (P<0.0001), and inhibited progesterone (P4) secretion in basal conditions or in the presence of low (0.5 ng/ml) FSH concentrations only (P<0.0001). The anti-alpha(6) IgG effect was specific to an interaction of LN with alpha(6)beta(1) integrin since it was ineffective on GC cultured on heat-denatured LN, RGD (arginine-glycine-aspartic acid) peptides and non-coated substratum. Hence, this study established that alpha(6)beta(1) integrin 1) was expressed in GC of antral follicles, 2) mediated the actions of LN on survival, proliferation and steroidogenesis of GC, and 3) was able to dramatically modulate P4 and E2 secretion by GC in vitro. It is suggested that during the follicular and the preovulatory phases of the estrous cycle, the increasing levels of LN in GC of large antral follicles might support their final development to ovulation.

Relationships between follicle-stimulating hormone, follicle growth and ovulation rate in sheep

The changes in follicle-stimulating hormone (FSH) concentration required to affect follicle growth and ovulation rate within individual ewes were examined. Relationships between peripheral FSH concentrations during the late-luteal and follicular phase and subsequent ovulation rates were investigated in 22 ewes from 4 breeds over 3 successive cycles (Experiment 1). Ewes were grouped as follows: Group 1 (n = 6), ewes exhibiting the same ovulation rate at each oestrous cycle: Group 2 (n = 5), ewes with three different ovulation rates at each oestrous cycle; and Group 3 (n = 11), ewes with the same ovulation rate at two oestrous cycles and a different ovulation rate on one occasion. Data from ewes in Group 1 and 3 provided estimates on the variation in FSH concentrations between cycles which were not large enough to alter ovulation rate (range, 0-67% variation in FSH concentration). In Group-2 ewes, there was no consistent association between increases in ovulation rate and the proportional increases in FSH concentrations. Differences in FSH concentrations were often less than those that did not alter ovulation rate in Group-I ewes. Furthermore, only 3 of 11 Group-3 ewes demonstrated high FSH concentrations associated with high ovulation rate (or low FSH concentrations and low ovulation rate) when compared with the concentrations found at the two cycles in which ovulation rate was similar. Hence, there was little evidence that FSH concentrations during the late-luteal and follicular phase are associated with changes in ovulation rate within individual ewes. In Experiment 2, follicles of similar size obtained from the same ewe (FecBFec+ and Romanov) showed markedly different responses in vitro to graded doses of FSH as measured by aromatase activity. It is concluded that, within a ewe, the large variability between gonadotrophin-dependent follicles in their requirement for FSH prevented the expression of any thresholds of ovarian response to FSH.

Protein kinases and protein synthesis are involved in desensitization of the plasminogen activator response of rat Sertoli cells by follicle-stimulating hormone

Tissue-type plasminogen activator (tPA) secretion is a specific response of Sertoli cells to follicle-stimulating hormone (FSH), which is lower after preincubation of the cells with low FSH concentrations because of FSH receptor/G s protein uncoupling. In this report, we present evidence that this desensitization induced by the lowest FSH concentrations is suppressed by specific peptidic inhibitors of endogenous PKA and PKC in permeabilized Sertoli cells. In contrast, desensitization promoted by slightly higher FSH concentrations is not mediated through PKA or PKC activation but is dependent on protein neosynthesis.

Clomiphene citrate augments follicle-stimulating hormone-induced luteinizing hormone receptor content in cultured rat granulosa cells

Although clomiphene citrate (CC) has been widely used for ovulation induction, the mechanism of its pro-fertility effect is not entirely clear. Because CC augments ovarian aromatase activity, the effect of CC on follicle-stimulating hormone (FSH)-induced luteinizing hormone (LH) receptor content was examined in primary cultures of rat granulosa cells. Control cultures contained low LH receptor content, whereas FSH stimulated LH receptor formation in a dose-dependent manner. The concomitant addition of CC enhanced FSH potency as shown by a decrease in the ED50 for FSH by 2.2-fold. Some cells were treated with a low concentration of FSH (12 ng/ml) in the presence or absence of increasing concentrations of CC (10(-8) M to 10(-6) M). The enhancement of FSH-stimulated LH receptor formation was found to be CC dose dependent, with an ED50 of 6 X 10(-8) M. Thus, CC may play a direct ovarian role in the enhancement of FSH-stimulated LH receptors. The gonadal action of this compound may be relevant in understanding the efficacy of CC in ovulation induction.

Calcium-dependent regulation of progesterone production by isolated rat granulosa cells: effects of the calcium ionophore A23187, prostaglandin E2, dl-isoproterenol and cholera toxin.

The role of calcium in the regulation of ovarian steroidogenesis was investigated in granulosa cells from estradiol-treated immature rats. Incubation of granulosa cells with various calcium channel blockers (verapamil, cobalt or manganese) and a calcium chelator (EGTA) resulted in marked decreases in progesterone production in response to follicle-stimulating hormone (FSH), cholera toxin, prostaglandin E2, dl-isoproterenol and dibutyryl cyclic AMP (Bt2cAMP). Cyclic AMP production, however, was unaffected by treatment with EGTA and verapamil at concentrations which attenuated steroidogenesis (0.1-1.0 mM and 125 microM, respectively). Two inhibitors of the calcium-dependent regulatory protein, calmodulin [trifluoperazine, 40 microM and 1[bis-(p-chlorophenyl)methyl] 3-[2,4-dichloro-beta-(2,4- dichlorobenzyloxy )-phenethyl]imidazolium chloride, ( R24571 ) 20 microM] significantly inhibited both cyclic AMP and progesterone production elicited by these stimulatory agents. Over the concentration range of 62.5 ng/ml-1.0 micrograms/ml, the calcium ionophore A23187 increased basal progesterone production in a dose-dependent manner, with half-maximal stimulation at approximately 0.14 microgram/ml. Maximal steroidogenic response to the calcium ionophore (1 microgram/ml) however, was only 50% of that evoked by FSH (0.33 microgram/ml). A23187 (0.5 microgram/ml) significantly enhanced progesterone production stimulated by a low concentration of FSH (0.025 microgram/ml) but failed to potentiate the maximally stimulatory action of the gonadotropin (0.33 microgram/ml). These findings support our earlier suggestion that the calcium-calmodulin system plays a central role in the gonadotropic regulation of ovarian steroidogenesis and suggest that a transmembrane flux of extracellular calcium may be an important and common step in the mechanism of stimulation of granulosa cell progesterone production.

Regulation of alpha subunit synthesis by gonadal steroid feedback in the sheep anterior pituitary.

Cell-free translations of ovine pituitary RNA were used to examine the amount of alpha subunit synthesized in the presence and absence of physiological levels of gonadal steroids. Two animal groups were used: 1) no feedback-castrate ewes exhibiting high serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and 2) negative feedback-castrate ewes treated with estradiol and progesterone which suppressed LH and FSH secretion. Cytoplasmic RNA was extracted from the pituitaries, translated in a wheat germ cell-free system, and alpha subunit identified by specific immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gels. Low amounts of alpha subunit (0.06% of total incorporated trichloroacetic acid-insoluble cpm) were seen in steroid-treated castrate ewes which also exhibited low serum LH and FSH concentrations. The amount of alpha translated by pituitary RNA from untreated castrates was significantly higher than those amounts from the steroid-treated castrates (p less than 0.02). The decreased amount of translated alpha subunit in steroid-treated castrates was probably not due to unique in vitro translation properties since the isotope incorporated/microgram of RNA and the amount of translated growth hormone and prolactin were similar for all RNAs. The results obtained from this animal model system suggest that the chronic negative feedback action of gonadal steroids on the gonadotropic hormones is effected, in part, via inhibition of synthesis of the alpha subunit of LH and FSH.

Anovulatory Menstrual Cycles in the Rhesus Monkey: The Significance of Serum Follicle-Stimulating Hormone/Luteinizing Hormone Ratios

Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17β-estradiol, and progesterone were determined for samples collected daily from seven mature rhesus monkeys during anovulatory menstrual cycles. Menstrual cycles in four monkeys were characterized by (1) low serum FSH concentrations, (2) a remarkably stable pattern of FSH secretion throughout the cycle, (3) low serum estradiol concentrations which varied little during the intermenstrual interval, and (4) low serum LH concentrations. Two monkeys had high serum FSH concentrations without the normal postmenstrual pattern of declining FSH concentrations to a preovulatory nadir. Estradiol concentrations increased progressively from 70 to 193 pg/ml over the first 18 days of the cycle in one monkey with high FSH levels and then sharply declined, suggesting follicular atresia. The seventh monkey had normal serum FSH levels, a normal pattern of FSH secretion, and normal FSH. LH ratios. The serum estradiol level in this animal increased from 62 to 327 pg/ml over the first 11 days of the menstrual cycle and then declined precipitously without a surge in gonadotropins, suggesting a functional deficiency at the hypothalamic or pituitary level. These data, taken in concert with our previous observations on abnormal corpus luteum function in the rhesus monkey, illustrate that the optimal growth, maturation, ovulation, and luteinization of the follicle are dependent upon (1) sufficient concentrations of both FSH and LH in the serum, (2) an appropriate pattern of FSH secretion, (3) an appropriate ratio of serum FSH:LH, and (4) an ovulatory surge of gonadotropins.

Serum gonadotropins before, at the inception of, and following human pregnancy.

Serum gonadotropins were determined by radioimmunoassay before at the inception of and following human pregnancy. The subject studied during an ovulatory cycle and ensuing pregnancy was a 21-year-old primiparous female with no abnormalities noted. Also daily levels of luteinizing hormone-human chorionic gonadotropin (LH-HCG) and follicle stimulating hormone (FSH) of a 24-year-old primiparous female were determined from 5 to 74 days after delivery. The results indicated the presence of low FSH levels at the inception of and immediately following pregnancy. The specificity of the FSH radioimmunoassay was suggested by low FSH concentrations in the face of increasingly high HCG levels. The different patterns of FSH and LH (FSH rising and remaining relatively constant prior to the slow rise in LH) suggest that FSH determinations were not influenced by the LH present. Suppression of FSH and the slow return to normal levels of LH following delivery suggest suppression of LH during pregnancy.