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PubMed2001

Simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue (F-G-test) allows effective drug regimen selection for IVF.

To determine whether preliminary assessment of ovarian reserve by simultaneous evaluation of basal follicle-stimulating hormone (FSH) and oestradiol response to gonadotrophin releasing hormone (GnRH) analogue (F-G-test) can be used to tailor individually the drug regimen for ovarian stimulation, the in-vitro fertilization (IVF) results of 238 patients were retrospectively analysed. Sixty-two women with abnormal response to the test (DeltaE2 <180 pmol/l and/or FSH >9.5 mIU/ml) had commenced buserelin nasal spray in the mid-luteal phase and discontinued it on cycle day 1. Ovarian stimulation was started on cycle day 3 with 375 IU/day of gonadotrophin. Fifty-three patients completed the treatment cycle (group A). A total of 176 women with normal response to the test (DeltaE2 >180 pmol/l and FSH <9.5 mIU/ml) had continued the GnRH analogue throughout the stimulation cycle and a starting dose of 225 IU/day of gonadotrophin was used from cycle day 3. A total of 158 patients completed the treatment cycle (group B). Group A had significantly higher age (34.9 +/- 4.2 versus 33.2 +/- 4.2) (P < 0.05) and basal FSH (9.2 +/- 3.8 versus 7.0 +/- 2.2) (P < 0.05) and required a higher total dose of gonadotrophin. The numbers of oocytes retrieved and embryos transferred were significantly lower. However, fertilization, clinical pregnancies, and implantation rates were similar in both groups. It was concluded that simultaneous evaluation of basal FSH and oestradiol response to GnRH analogue can be useful in identifying subcategories of women with reduced ovarian reserve who may benefit from reduced GnRH analogue administration and a higher starting dose of gonadotrophin.

Adult↗
PubMed2002

Basal FSH, estradiol and inhibin B concentrations in women with a previous Down's syndrome affected pregnancy.

BACKGROUND: Two recent studies reported elevated basal FSH concentrations in women with a history of aneuploid conceptions. However, it is not known whether these elevated basal FSH concentrations reflect depletion of the primordial follicle pool, or were caused by an increased secretory drive for FSH. METHODS: Inhibin B and estradiol concentrations were measured as indicators for depletion of the primordial follicle pool in women with a history of a Down's syndrome pregnancy and in controls. RESULTS: In the women with a history of a Down's syndrome pregnancy, there was a significant inverse correlation between basal FSH and inhibin B concentrations (P < 0.0001, 95% CI -0.26 to -0.56). In the control group, this correlation did not reach statistical significance. CONCLUSIONS: Our data indicate that the elevated basal FSH concentrations observed in women with a history of a Down's syndrome pregnancy are likely to reflect early depletion of the primordial follicle pool. Therefore, further research into the ovarian ageing process could provide more insight in the origination of chromosomal abnormalities during pregnancy.

Adult↗
PubMed2002

Serum inhibins, estradiol, progesterone and FSH in surgical menopause: a demonstration of ovarian pituitary feedback loop in women.

BACKGROUND: The objective of this study was to confirm the source and study the acute changes and relationship between inhibins and FSH at surgical menopause. METHODS: Regularly cycling women (42-47 years; n = 10) undergoing bilateral oophorectomy for non-ovarian pathology were recruited for this study. One blood sample was taken before surgery and after removal of the ovaries, samples were taken every 15 min up to 1 h, hourly up to 6 h, after 12 h and daily during the hospital admission (3 days). RESULTS: There were five women in the follicular phase and five women in the luteal phase of the cycle. For women in both phases, levels of inhibin A, inhibin B, estradiol (E(2)) and progesterone decreased after the removal of the ovaries. Serum FSH levels started to rise after 12 h in both follicular and luteal phase women after the surgical menopause. Correlation analysis showed that inhibin A and E(2) were significantly negatively correlated in both phases with FSH concentration. Inhibin B had a negative correlation in the follicular phase and progesterone had a negative correlation in the luteal phase. CONCLUSIONS: This study showed that ovarian inhibin A and B were cleared from the circulation within 12 h of oophorectomy, whereas E(2) and progesterone remain in the circulation for longer. Negative correlation between FSH, inhibin A and inhibin B suggests that inhibins may contribute to the observed early rise in FSH after the surgical menopause.

Adult↗
PubMed2002

Comparison of day 3 FSH serum values as determined by six different immunoassays.

BACKGROUND: The accurate assessment of FSH concentration is important for evaluating ovarian function prior to IVF. However, a number of different assay techniques are currently in use, leading to inconsistencies in the hormone data being reported. To address this problem, we measured FSH concentration using a number of commercially available systems. METHODS: Day 3 serum FSH levels were measured in 215 healthy fertile women using six different immunoassays: Coatria (125)I (Bio-Mérieux), ACS-180 (Bayer Diagnostics), Advia-Centaur (Bayer Diagnostics), Vitros ECi (Ortho-Clinical Diagnostics), Architect i2000 (Abbott) and Elecsys 2010 (Roche Diagnostics). RESULTS: According to the immunoassay, means +/- SD of FSH concentrations were: 6.5 +/- 2.2 mIU/ml for Coatria (125)I, 6.8 +/- 2.7 mIU/ml for Advia-Centaur, 6.7 +/- 3.0 mIU/ml for Vitros ECi, 7.6 +/- 3.0 mIU/ml for ACS-180, 8.2 +/- 3.3 mIU/ml for Architect i2000 and 8.8 +/- 3.0 mIU/ml for Elecsys 2010. CONCLUSION: Day 3 FSH values determined by six different immunoassays were significantly different (P < 0.01, paired t-test). Physicians must take care when interpreting results from different clinical laboratories.

Female↗
PubMed2002

Value of measuring serum FSH in addition to serum estradiol in a coasting programme to prevent severe OHSS.

BACKGROUND: Withholding gonadotrophins (coasting) can reduce the risk of severe ovarian hyperstimulation syndrome (OHSS) in patients having assisted reproduction therapy. This requires daily serum estradiol (E(2)) measurements, which occasionally have been seen to decline suddenly and sharply. METHODS: To increase the sensitivity of the coasting programme we measured serum FSH in parallel with E(2) in patients at risk of developing OHSS. RESULTS: Out of a total of 1240 cycles, 106 were coasted and in 89 both serum E(2) and FSH were measured at least twice during the coasting period. One case of late severe OHSS was encountered in the study group. The serum FSH declined by a rate of 24.3 +/- 4.5% per day. Serum E(2) level reached a 'safe level' of <10,000 pmol/l when the serum FSH declined to 5 IU/l or less. CONCLUSION: The results from this study show that measuring serum E(2) and FSH can assist in predicting the point at which serum E(2) has declined to a level safe enough to administer the trigger HCG.

Adult↗
PubMed2004

A randomized controlled trial of hysterectomy or levonorgestrel-releasing intrauterine system in the treatment of menorrhagia-effect on FSH levels and menopausal symptoms.

BACKGROUND: The purpose of this study was to compare the effects of hysterectomy and a levonorgestrel-releasing intrauterine system (LNG-IUS) on serum FSH levels and menopausal symptoms. METHODS: A total of 236 women referred for menorrhagia to five university hospitals were randomly assigned to treatment with hysterectomy (n = 117) or LNG-IUS (n = 119). Menopausal symptoms were characterized by the Kupperman menopausal distress test. Serum FSH and estradiol levels were measured at baseline and 6 and 12 months after hysterectomy or application of LNG-IUS. Analyses were by intention to treat. RESULTS: After 6 months, there was no difference between the groups, but 12 months after follow-up hysterectomized women had higher FSH levels than women with LNG-IUS (P = 0.005). There was a significant association between FSH levels and treatment modality (P = 0.020). Hot flushes increased significantly in the hysterectomy group (P = 0.02). There was a significant association between hot flushes and both treatment modality and age (P = 0.02 and P = 0.01, respectively). CONCLUSION: Hysterectomy may impair ovarian function shown by rising serum FSH levels and hot flushes. However, these results should be interpreted with caution, and longer follow-up is needed.

Adult↗
PubMed2004

Synergistic effects between FSH and 1,1-dichloro-2,2-bis(P-chlorophenyl)ethylene (P,P'-DDE) on human granulosa cell aromatase activity.

BACKGROUND: 1,1-Dichloro-2,2-bis(P-chlorophenyl)ethylene (P,P'-DDE, DDE), a metabolite of DDT, is a persistent hormonally active environmental toxicant which has been found in human serum and follicular fluid. The objective of this study was to investigate the interaction between FSH and ppDDE on aromatase activity in primary cultures of human granulosa cells. METHODS: Granulosa cells were obtained at the time of oocyte retrieval for IVF procedures and cultured in defined medium containing FSH and environmentally relevant concentrations of DDE. Aromatase activity was measured by incubating the cells with 1beta-[(3)H]androstenedione and measuring the release of (3)H(2)O. RESULTS: The granulosa cell response to FSH was highly dependent on the basal level of aromatase activity (r = -0.703, P = 0.001, n = 17) with the highest activity occurring at low basal levels of aromatase activity. Enzyme activity was significantly stimulated at 100 ng DDE/ml. A synergistic effect on aromatizing activity was observed when cells were co-cultured with DDE and FSH. CONCLUSIONS: Concentrations of DDE similar to those present in human follicular fluid enhance basal and FSH-stimulated granulosa cell aromatizing enzyme activity.

Aromatase↗
PubMed2004

Anti-Müllerian hormone plasma levels in spontaneous menstrual cycle and during treatment with FSH to induce ovulation.

BACKGROUND: Anti-Müllerian hormone (AMH) is member of the transforming growth factor-beta superfamily of growth factors. AMH is detected in serum from women of reproductive age and its levels vary slightly with the menstrual cycle, reaching the peak value in the late follicular phase. The present study was undertaken to assess the effect of controlled ovarian stimulation on AMH secretion by the ovary in healthy women in order to obtain more insight into the relationship between this peptide and gonadal steroids. METHODS: Twenty-four normally cycling women attending the infertility clinic volunteered for this study and AMH was measured in blood samples obtained during both spontaneous and FSH-treated cycles. RESULTS: AMH plasma levels did not change significantly from day 2 to day 6 in spontaneous cycles. On the contrary, AMH levels decreased progressively from day 2 to day 6 in FSH-treated cycles. A significant positive correlation was found between the decrease in AMH and the increase in estradiol plasma levels in FSH-treated cycles and between basal AMH and the peak estradiol (E2) during exogenous FSH administration. CONCLUSIONS: The present study demonstrated that AMH plasma levels did not change during the follicular phase of the menstrual cycle and that exogenous FSH administration is followed by a significant reduction in AMH levels which is probably secondary to the gonadotrophin effect on the process of follicular development.

Adult↗
PubMed2004

Reproductive ageing and ovarian function: is the early follicular phase FSH rise necessary to maintain adequate secretory function in older ovulatory women?

BACKGROUND: Serum FSH elevations and decreases in inhibin B have been consistently demonstrated in the early follicular phase of cycles in women of advanced reproductive age. However, secretory products of the dominant follicle (estradiol and inhibin A) in the serum of older ovulatory women are maintained at levels similar to those of their younger counterparts. The goal of this investigation was to determine if ovarian secretory capacity is dependent on relative FSH levels and if basal measures of ovarian reserve reflect ovarian secretory capacity. METHODS: We administered equivalent low, but effective doses of recombinant FSH for 5 days to a group of older subjects (40-45 years, n=9) and younger controls (20-25 years, n=10) after pituitary suppression with a GnRH agonist. Outcome measures included follicular development as determined by serial transvaginal ultrasound examinations and serum levels of estradiol, inhibin A and inhibin B. RESULTS: Serum levels of estradiol and inhibin A were not statistically different between the two groups, while the number of large follicles formed was greater in the younger subjects. Basal parameters of ovarian reserve were not significantly correlated with ovarian secretory capacity, but did correlate with the number of follicles recruited in response to low-dose FSH. CONCLUSIONS: By providing equivalent serum levels of FSH in older and younger reproductive aged women, this study demonstrates that the secretory capacity of recruited follicles is maintained in older reproductive aged women.

Adult↗
PubMed2005

Alternate day and daily administration of GnRH antagonist may prevent premature luteinization to a similar extent during FSH treatment.

BACKGROUND: This randomized controlled trial was designed to evaluate whether a GnRH antagonist given every other day could prevent premature luteinization in women undergoing IVF/ICSI treatment. METHODS: A total of 73 women receiving ovulation stimulation IVF cycles with recombinant FSH were allocated randomly on cycle day 7 to GnRH antagonist ganirelix in multiple doses (0.25 mg each), either daily (n = 37 women, group 1) or every other day (n = 36 women, group 2) until the day of HCG administration. RESULTS: Serum FSH, LH, estradiol and progesterone values showed similar trends in the two groups. During FSH stimulation, 13 (35%) of the women in group 1 had premature LH rises (> or = 10 IU/l) of which eight (22%) were after the start of antagonist administration. In group 2 there were 14 (39%) LH rises during FSH stimulation of which 10 (28%) were after the start of antagonist administration. Luteinization (serum progesterone >2 ng/ml) occurred in only one woman in each group overall (3%). A significantly smaller total dose of the antagonist was used in group 2 than in group 1 (P < 0.001). The study did not have power to evaluate differences in total dose of FSH, number of oocytes recovered and clinical pregnancy rate, all of which appeared similar in the two groups. CONCLUSIONS: Whether alternate day is as effective as daily administration of ganirelix in preventing premature luteinization should be addressed in a non-inferiority trial powered to evaluate live birth rate.

Adult↗
PubMed1999

FSH-induced resumption of meiosis in mouse oocytes: effect of different isoforms.

The ability of different isoforms of follicle stimulating hormone (FSH) to induce the resumption of meiosis in cultured mouse oocytes was evaluated. Oocytes were cultured in the presence of hypoxanthine to prevent spontaneous resumption of meiosis. Using serial dilutions of the isoform fractions representing less acidic isoforms (pI 6. 43-5.69), mid-acidic (pI 5.62-4.96) and acidic (pI 4.69-3.75), the concentration which caused 50% of the oocytes to resume meiosis and undergo germinal vesicle breakdown (GVBD) after a culture period of 24 h (i.e. ED(50%) GVBD) was determined. The FSH concentration of the isoform fractions was determined by radioimmunoassay, radio-receptor assay or through cAMP release in a Chinese hamster ovary-cell line expressing the human FSH-receptor. Determined by radioimmunoassay, the (ED(50%) GVBD) values were: less acidic 6.4 +/- 0.3 IU/l (mean +/- SD), mid-acidic 6.1 +/- 0.7 IU/l and acidic 12.2 +/- 0.7 IU/l. The less and mid-acidic isoforms were significant lower than the acidic (P < 0.0005). Similar relationships between the isoform fractions were obtained by the two other FSH assays. The results demonstrate that FSH isoforms with a pI of >5.0 induced resumption of meiosis significantly more efficiently than acidic isoforms. Less and mid-acidic isoforms may exert an important physiological function by inducing the resumption of meiosis in oocytes from pre-ovulatory follicles during the mid-cycle gonadotrophin surge.

Animals↗
PubMed2002

FSH and LH induce progesterone production and progesterone receptor synthesis in cumulus cells: a requirement for meiotic resumption in porcine oocytes.

The aim of this study was to investigate the role of progesterone in the meiotic resumption of porcine oocytes. Progesterone production and progesterone receptor (PR) immunoreactivity in cumulus cells were not detected in porcine cumulus-oocyte complexes (COC) when observations were made either just after collection from the follicles or after 28 h cultivation without LH and FSH. However, the addition of LH and FSH induced PR expression in cumulus cells, concomitant with increased progesterone production. To assess the role of progesterone in the COC, an inhibitor of progesterone production, aminoglutethimide (AGT), was administered. The addition of AGT to the medium with LH and FSH significantly suppressed progesterone production in a dose-dependent fashion. When COC were cultured with LH, FSH and 0.5 x 10(-3) mol/l AGT, almost complete inhibition of progesterone production and of germinal vesicle breakdown (GVBD) was seen. However, this inhibitory effect on GVBD was overcome by additional progesterone. Moreover, 0.5 x 10(-3) mol/l AGT also suppressed the reduction in connexin43, a gap junctional protein, in cumulus cells after 28 h cultivation, and increased the level of cyclic AMP in oocytes. These results support the hypothesis that the binding of progesterone, which was secreted by LH- and FSH-stimulated cumulus cells, to its newly synthesized receptor induces GVBD in porcine oocytes, possibly through a reduction of connexin43 in cumulus cells.

Animals↗
PubMed1988

The effect of age on the cyclical patterns of plasma LH, FSH, oestradiol and progesterone in women with regular menstrual cycles.

Luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestradiol and progesterone concentrations in plasma were obtained daily throughout the menstrual cycles of 94 regularly cycling women, aged between 24 and 50 years. Although mean LH concentrations changed little with advancing age, mean FSH concentrations were significantly (P less than 0.001) elevated from the age of 39 years. FSH concentrations in the oldest women studied (48-50 years) were approximately 3-fold greater than in the younger controls (women aged 23-35 years). LH concentrations rose slightly (P less than 0.05) during the last 5 years only. The increase in FSH concentration was not, however, uniform across the cycle, but was confined predominantly to the mid-follicular and post-ovulatory phases (i.e. those times in the normal menstrual cycle when circulating inhibin concentrations appear to be minimal). Despite the clear increases in FSH concentration, there was little alteration in the mean steroid profiles which remained within the normal fertile range throughout the last decade of reproductive life. The only exception to this was a small, transient, but significant (P less than 0.05) decrease in preovulatory oestradiol concentration between the ages of 36 and 38 years, which was followed by a transient increase (P less than 0.01) in oestradiol concentration between 39 and 44 years. However, no corresponding significant changes in mean progesterone concentrations were observed.

Adult↗
PubMed2006

Adult sertoli cells are not terminally differentiated in the Djungarian hamster: effect of FSH on proliferation and junction protein organization.

Sertoli cell number is considered to be stable and unmodifiable by hormones after puberty in mammals, although recent data using the seasonal breeding adult Djungarian hamster (Phodopus sungorus) model challenged this assertion by demonstrating a decrease in Sertoli cell number after gonadotropin depletion and a return to control levels following 7 days of FSH replacement. The present study aimed to determine whether adult Sertoli cells are terminally differentiated using known characteristics of cellular differentiation, including proliferation, junction protein localization, and expression of particular maturational markers, in the Djungarian hamster model. Adult long-day (LD) photoperiod (16L:8D) hamsters were exposed to short-day (SD) photoperiod (8L:16D) for 11 wk to suppress gonadotropins and then received exogenous FSH for up to 10 days. Sertoli cell proliferation was assessed by immunofluorescence by the colocalization of GATA4 and proliferating cell nuclear antigen and quantified by stereology. Markers of Sertoli cell maturation (immature, cytokeratin 18 [KRT18]; mature, GATA1) and junction proteins (actin, espin, claudin 11 [CLDN11], and tight junction protein 1 [TJP1, also known as ZO-1]) also were localized using confocal immunofluorescence. In response to FSH treatment, proliferation was upregulated within 2 days compared with SD controls (90% vs. 0.2%, P < 0.001) and declined gradually thereafter. In LD hamsters, junction proteins colocalized at the basal aspect of Sertoli cells, consistent with inter-Sertoli cell junctions, and were disordered within the Sertoli cell cytoplasm in SD animals. Exogenous FSH treatment promptly restored localization of these junction markers to the LD phenotype. Protein markers of maturity remain consistent with those of adult Sertoli cells. It is concluded that adult Sertoli cells are not terminally differentiated in the Djungarian hamster and that FSH plays an important role in governing the differentiation process. It is proposed that Sertoli cells can enter a transitional state, exhibiting features common to both undifferentiated and differentiated Sertoli cells.

Actins↗
PubMed2006

Fetal gonadotrope cell origin of FSH-secreting pituitary adenoma - insight into human pituitary tumour pathogenesis.

OBJECTIVE: The pathogenesis of human pituitary adenomas remains unclear, but we report a case of FSH-secreting pituitary adenoma whose monohormonal phenotype suggests it was of fetal origin. PATIENTS: A 28-year-old woman presented with abdominal discomfort and irregular menses, enlarged multicystic ovaries and elevated serum oestradiol, with sustained high-normal FSH and low LH levels. MEASUREMENTS: Endocrine studies were performed before and after curative surgery, with assessment of tumour hormone secretion in vitro, and immunostaining of tumour tissue for a series of gonadotrope proteins. RESULTS: Immunocytochemistry showed that tumour cells were monohormonal for FSH. Normal components of gonadotrope signalling pathways were expressed, including oestrogen receptor-alpha, activin receptors, secretogranin-II and chromogranin-A. beta-glycan, the putative inhibin coreceptor, was absent. Tumour culture in vitro confirmed secretion of FSH with minimal LH, that was unsuppressed by oestradiol or inhibin-A. Human fetal pituitary tissue contained FSH-only cells at 18 weeks gestation, whereas normal adult pituitary tissue contained only bihormonal gonadotropes. CONCLUSIONS: We propose that this pituitary adenoma represents an indolent tumour of monohormonal fetal gonadotrope cells that originated early in gestation. Pituitary tumours may therefore arise from abnormal persistence of fetal cell types, with extremely slow growth over many years until reaching a size threshold to generate an endocrine syndrome. Understanding fetal pituitary architecture and function may be more informative for new insights into pituitary tumour pathogenesis than classical theories of cancer biology that invoke unrestrained cell proliferation.

Adenoma↗
PubMed1988

Spermatogenic onset. II. FSH modulates mitotic activity of germ and Sertoli cells in immature rats.

By using high doses of testosterone propionate (TP) endogenous FSH was lowered to non-detectable levels in immature rats of different ages. Combined administration of TP and human menopausal gonadotrophin (hMG) or purified human FSH (hFSH) restored circulating FSH to normal or supranormal levels. This experimental model was used to investigate the influences of hormones on the proliferation of Sertoli and germ cells. Mitoses in seminiferous tubules were counted after being blocked by administration of colchicine. The mitotic index so determined showed a reduction with FSH withdrawal and a significant increase when the hormone levels were restored. Testicular DNA content was determined in testicular homogenates and showed similar changes. Autoradiographs were prepared and 3H-thymidine incorporation into germ and Sertoli cells was quantified. It was found that hFSH induced a significant increase in the labelling indices of gonocytes, type A-spermatogonia and Sertoli cells. All of these changes were effective in rats younger than 10 days but no modifications in any of the parameters under study were observed after 20 days. It is concluded that FSH exerts a stimulatory effect on the proliferation of spermatogonia, Sertoli cells and testicular DNA content during the first 10 days of life.

Animals↗
PubMed1995

Annual variations of in vitro GNRH release by hypothalamic explants in intact and castrated male mink: relations with LH, FSH and testosterone circulating serum levels.

In mink, a short-day breeder, testis growth begins in autumn (November), reaches a maximum in February, before matings occur, and decreases from March to very low volumes during spring and summer. To study the effects of season and testosterone feedback on gonadotrophin and GnRH secretion, the annual variations of LH, FSH, testosterone and GnRH were studied in intact and castrated mink. As portal blood sampling raised serious difficulties, an in vitro static incubation system was used for studying GnRH variations. In intact mink, serum LH concentrations did not vary significantly throughout the year, whereas FSH concentrations increased significantly between September and November then decreased to a minimum in January. Testosterone values rose significantly from November to a maximum from January to March, decreased very rapidly thereafter. Castration in November resulted in a significant increase in LH and FSH concentrations which remained higher than the values measured in intact males throughout the year. In long-term castrated mink, FSH concentrations did not fluctuate during the year, whereas LH concentrations showed an annual variation, with high values in April and August. For the study of in vitro GnRH liberation, medio-basal hypothalamic explants were incubated in Krebs-Ringer phosphate buffer for 3 periods of 15 min, and stimulated with copper complexed equimolarly with histidine (Cu/His, 200 microM) and prostaglandin E2 (PGE2, 10 microM). After Cu/His, the release of GnRH was 1 to 4 fold the basal release; after PGE2, the increase was 4-7 fold the basal release. The basal release of GnRH increased significantly between September and October to reach a maximum in November, decreased significantly in December to a minimum in February then increased progressively from May. The release of GnRH stimulated by Cu/His and PGE2 showed the same seasonal variation as the basal release. Castration 8 days before the sacrifice did not alter the release of GnRH, except in December: the release stimulated by PGE2 was then higher in intact than in castrated mink. Taken together, these results indicate that, with an in vitro static incubation system, it is possible to study the annual variations of GnRH release and to correlate these variations with those of serum gonadotrophin and testosterone concentrations. The synthesis and release of GnRH increased slightly from May, under long days, then more rapidly from September, resulting in an increased secretion of FSH in October, responsible for testis recrudescence. The annual pattern of basal and stimulated GnRH release was similar in intact and castrated mink, suggesting a direct effect of the season on the hypothalamus, rather than a negative feedback effect of the testis; however, testosterone seemed to feedback mainly at the pituitary level.

Animals↗
PubMedDate not supplied

Some interrelationships between plasma levels of LH, FSH, oestradiol 17beta, androgens and semen analysis data in male infertility patients.

Serum LH, FSH and immunoreactive testosterone-like substances (TLS) have been measured by radioimmunoassay in 130 male infertility patients and oestradiol 17beta in 26 cases. A weak but significant negative correlation was found between FSH and sperm count (rs = -0.19, p less than 0.05) but not LH and sperm count. However, LH and FSH were strongly correlated in the azoospermic (rs = 0.71, p less than 0.01) and oligozoospermic (rs = 0.53, p less than 0.01) groups and levels of both gonadotrophins were significantly elevated in the azoospermic and oligozoospermic as compared to the normozoospermic group. The elevated LH levels in the oligozoo- and azoospermic groups could not be explained by reduced negative feedback of testosterone or oestradiol 17beta since firstly, TLS and oestradiol 17beta levels were similar in all three groups and, secondly, within-group correlations between LH and TLS were either non-significant or positive (azoospermic group r = 0.37, p = 0.06). It is suggested that spermatogenesis-related feedback factor(s) may inhibit LH as well as FSH secretion. No role for oestradiol 17beta as a selective inhibitor of FSH secretion seemed likely as oestradiol 17beta levels were similar in the three groups and were correlated (r = 0.51, p less than 0.01) to TLS levels i.e. to leydig cell rather than spermatogenic function. Seminal fructose was negatively correlated (r = -0.26, p less than 0.01) with sperm count but not significantly with plasma TLS. It would thus seem unlikely that the tendency for seminal fructose levels to increase as sperm count decreases is due to increased androgen production or that seminal fructose can be used as an index of a patient's androgenic status. Patients with varicoceles had hormone levels similar to other patients of similar sperm count. Both sperm morphology and motility were strongly correlated to log sperm count (r = 0.84 and 0.55 respectively) and semen volume was significantly greater in oligozoospermic than normozoospermic patients (p less than 0.01).

Androgens↗