Relationship between human follicular fluid inhibin F activity and steroid content

17 beta-Oestradiol, androstenedione and inhibin levels in fluid from individual follicles of normal and polycystic ovaries, and in ovaries from androgen treated female to male transsexuals

OBJECTIVE

The aim was to monitor carefully follicular growth arrest in polycystic ovaries by assay of hormones in individual follicles.

DESIGN AND PATIENTS

Fluid from follicles less than or equal to 10 mm was obtained from ovaries of 16 regularly cycling women between days 1 and 12 of the follicular phase (controls, n = 120 follicles), polycystic ovaries of five women with polycystic ovary syndrome (n = 43), and polycystic ovaries from 14 long-term testosterone treated female to male transsexuals (n = 120).

MEASUREMENTS

Fluid was assayed for oestradiol, androstenedione, and immunoactive inhibin. Luteinizing hormone, follicle-stimulating hormone, and testosterone levels were estimated in serum.

RESULTS

Median serum LH was lower in transsexuals than in controls (P less than 0.05), and in polycystic ovary syndrome (P less than 0.01). Median serum testosterone was not significantly different between polycystic ovary syndrome and transsexuals, and was elevated in both groups as compared to controls (P less than 0.01). Oestradiol was present in all follicles obtained from polycystic ovaries of polycystic and transsexual patients, in which no follicle greater than 10 mm could be detected. In the three groups, between-patient differences in mean oestradiol, androstenedione, inhibin, and androstenedione/oestradiol ratio were significantly larger than expected in view of the variation between follicles within individuals. Taking into account this between-patient difference, no significant differences could be established between the three groups for all endocrine parameters. The percentage of presumed healthy follicles (androstenedione/oestradiol ratio less than or equal to 4) was 12% in controls, 17% in polycystics, and 14% in transsexuals, and was not significantly different between groups.

CONCLUSIONS

The results may indicate that (1) abnormally high circulating androgen concentrations with or without elevated LH levels disturb the process of selection, and could therefore play a role in the pathogenesis of polycystic ovaries; (2) in polycystic ovaries from polycystic ovary syndrome and transsexual patients, aromatase activity is present in vivo in small antral follicles, and the proportion of presumed healthy follicles is not different from that encountered in normal ovaries; (3) oestradiol levels are not different between non-dominant follicles of normal and polycystic ovaries, suggesting that only enhancement of aromatase activity by FSH may be disrupted in polycystic ovaries, (4) because androstenedione levels are not different comparing follicles of normal and polycystic ovaries, hyperandrogenaemia in the syndrome seems to originate from the abnormally high number of cystic atretic follicles generally observed in polycystic ovaries; (5) marked variation in the endocrine follicular microenvironment within and between-women precludes pooling fluid from several follicles.

Prediction of response to controlled ovarian hyperstimulation: a comparison of basal and clomiphene citrate-stimulated follicle-stimulating hormone levels

OBJECTIVE

To test the ovarian reserve in a high-risk population before controlled ovarian hyperstimulation for in vitro fertilization (IVF).

DESIGN

A prospective study comparing the outcome of a clomiphene citrate (CC) challenge test to the outcome of subsequent IVF cycles.

SETTING

Unit for assisted reproductive technology in a university hospital.

PATIENTS, PARTICIPANTS

Ninety-one infertile women with an age of 35 years or more, who had previous ovarian surgery or who had been diagnosed with ovarian endometriosis.

MAIN OUTCOME MEASURE

Relate follicle-stimulating hormone (FSH) levels before and after CC to frequency of cancellation of an IVF cycle because of a poor follicular response.

RESULTS

Twenty-one patients had elevated basal levels of FSH. Thirty-seven patients, including 20 with high basal levels, showed an excessive FSH response to CC with an FSH level after CC above the 95% confidence limit. Clomiphene citrate-stimulated FSH levels correlated better than basal levels with response to controlled ovarian hyperstimulation. An excessive FSH response to CC predicted a poor response outcome of subsequent controlled ovarian hyperstimulation for IVF with 85% accuracy.

CONCLUSION

Follicle-stimulating hormone response to CC predicts subsequent follicular response to controlled ovarian hyperstimulation.

Changes in the concentration of mRNAs for the inhibin subunits in ovarian follicles after administration of gonadotropins to progestin treated ewes

RNA was extracted from single or small groups of ovine ovarian follicles after treatment of ewes with FSH and/or LH. The content of mRNA for the alpha-inhibin and beta A-inhibin subunits was analyzed by hybridization with specific cDNA probes. All ewes were treated with progestin vaginal pessaries to suppress spontaneous preovulatory follicle maturation and ewes were given three intramuscular injections of gonadotropins at 8-hr intervals starting 24 hr prior to collection of ovaries. In experiment I, both Schering-FSH and NIDDK-oFSH-17 (oFSH) significantly increased alpha- and beta A-inhibin mRNA per ewe in 2-5 mm follicles and tended to increase alpha- and beta A-inhibin mRNA in large (greater than 5 mm) follicles. In experiment II, oFSH and NIDDK-oLH-25 (oLH) were administered in a 2X2 factorial arrangement. Separate administration of oFSH or oLH increased (P less than .05) the alpha-inhibin mRNA concentration in large follicles. alpha-inhibin mRNA concentration in 4-5 mm follicles was also increased by oFSH but was decreased by oLH. Concomitant treatment with oFSH and oLH did not change alpha-inhibin mRNA concentrations from those measured in oFSH treated ewes. In experiment II, beta A mRNA concentrations followed a pattern similar to that of alpha A mRNA, but the differences were not statistically significant. We conclude that, in the ewe, exogenous FSH increases the concentration of inhibin mRNA in the whole follicle. The ability of exogenous oLH to alter expression of the inhibin subunit genes may depend upon the stage of follicle maturation.

Inhibin and related proteins: localization, regulation, and effects

Inhibin has originally been defined as a gonadal hormone that exerts a specific negative feedback action on the secretion of FSH from the gonadotropic cells of the pituitary gland. The existence of inhibin was postulated by Mottram and Cramer (15) as early as 1923. However, only after reliable and sensitive bioassay systems had been developed for detection and estimation of inhibin and an ample source of inhibin was found in the form of ovarian follicular fluid, was progress made on the isolation and characterization of the hormone. It is apparent now that inhibin, which itself consists of a dimer of two different subunits, alpha and beta, is a member of a much larger family of (glyco)protein hormones and growth factors that includes Müllerian inhibiting substance, transforming growth factor-beta, activin/erythroid differentiation factor, bone morphogenetic proteins, and an insect and a Xenopus protein. All play important roles in cell differentiation. Gonadal inhibin is produced in the Sertoli cells in the testis and in the granulosa cells in the ovary. The production of inhibin is stimulated by FSH, but controversy exists about other factors that might play a role in the regulation of the production of inhibin. It appears likely that inhibin plays an important role in the feedback regulation of peripheral concentrations of FSH during the period in which Sertoli cells and granulosa cells--the target cells for FSH--divide, i.e., during puberty in male animals and during the development of ovarian follicles in female animals. In this way, inhibin may be an important regulator of the number of developing Sertoli cells and of the length of the seminiferous tubuli in the testis and of the number of developing follicles in the ovary. Apart from its function in the pituitary-gonadal axis, inhibin and activin may be produced and act in a number of other organs such as the placenta, hypothalamus, adrenal, and bone marrow. Investigation of the role of the members of the inhibin family in these systems has only begun, but will certainly be a field of major interest in the near future.

Follicular fluid steroid content and in vitro steroid secretion by granulosa-lutein cells from individual follicles among different stimulation protocols for in vitro fertilization-embryo transfer

The in vitro steroidogenic capacity of granulosa-lutein (G-L) cells aspirated from individual follicles during cycles of in vitro fertilization-embryo transfer was examined and compared among three different stimulation protocols: human menopausal gonadotropins (hMG), clomiphene citrate (CC) and hMG, and follicle stimulating hormone (FSH). In addition, the clinical outcome of the patients in each protocol was examined. After 3 days of culture in basal medium, fresh medium with or without androstenedione (A) (10(-7) M) was added for 24 hr, at which time medium was obtained for measurement of progesterone (P) and estradiol (E) content. Follicular fluid (FF) P, E, and A were measured in each follicle and compared among protocols. FF from individual follicles in patients stimulated with FSH contained higher levels of P compared to FF from patients stimulated with hMG or CC/hMG, while E was higher in patients stimulated with CC/hMG compared to FSH or hMG. FF levels of A were not significantly different among the protocols. In vitro steroid secretion revealed a progressive increase in P secretion in contrast to decreasing E secretion when one compares CC/hMG, hMG, and FSH. Patients undergoing ovarian hyperstimulation with FSH had significantly more atretic oocytes identified at the time of oocyte harvest compared to patients undergoing ovarian hyperstimulation with CC/hMG or hMG. The hMG protocol yielded significantly fewer fertilized oocytes, cleaved embryos, and transferred embryos, compared to the CC/hMG and FSH protocol, however, there was no significant difference in pregnancy rate among the three protocols. These data demonstrate that individual follicles contain G-L cells with markedly different abilities to luteinize in vitro as assessed by steroid secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of echographic and endocrine monitoring for the assessment of ovulation by follicle stimulating hormone in polycystic ovarian disease

Sixteen patients with polycystic ovarian disease (PCOD) were treated for 39 cycles with pure follicle-stimulating hormone (FSH) for the induction of ovulation. At ovulation time human chorionic gonadotropin (hCG) was administered. Twenty-one cycles were ovulatory. Twenty-three were classified as normostimulated (N): six pregnancies and three abortions were observed. In the remaining eight hyperstimulated (H) cycles there were four full-term pregnancies. Dosage and length of treatment were greater in patients with excess body weight (P less than 0.01). H cycles were characterized in respect to N cycles by: (1) higher baseline values of 17-hydroxy progesterone (17-OHP) plasma levels and LH/FSH ratios; (2) higher plasma concentrations and rate of increase of 17-OHP periovulatory levels. E2 plasma levels did not permit a clear differentiation between H and N cycles, and it was not useful for the timely recognition of hyperstimulation. Our data show that a slight controlled degree of ovarian hyperstimulation is beneficial to pregnancy rate and outcome.

Endocrine profile of follicles containing oocytes with subsequent polyploid fertilization

In an attempt to identify oocytes at risk for polypronuclear fertilization, follicular fluids were obtained retrospectively that contained oocytes that fertilized normally and abnormally. Whenever possible, each patient served as her own control during the same stimulation cycle. Twenty-six of 169 patients had oocytes that became polypronuclear, and of those 26, 21 had oocytes that fertilized and cleaved normally. Follicular fluids were analyzed for estradiol, progesterone, androstenedione, transferrin, and insulin. Insulin levels were noted to be significantly elevated (P less than 0.05) in the polypronuclear group when compropose that insulin, a known growth factor for granulosa cells cultured in vitro, when present in excessive concentrations may predispose to polypronuclear fertilization.

Inhibition of mouse oocyte cyclic AMP phosphodiesterase by steroid hormones: a possible mechanism for steroid hormone inhibition of oocyte maturation

Testosterone, progesterone, and estradiol-17 beta each inhibit cAMP phosphodiesterase activity of mouse oocyte extracts in a concentration-dependent manner. This finding provides an explanation for the inhibitory effect of steroid hormones on germinal vesicle breakdown (GVBD) of mouse oocytes in vitro. Furthermore, it raises the possibility that steroid hormones present in follicular fluid participate in maintaining meiotic arrest in vivo by acting in a nonclassical manner.

Use of individual human follicles to compare oocyte in vitro fertilization to granulosa cell in vitro luteinization

Granulosa-lutein (G-L) cells from individual follicles aspirated during cycles of in vitro fertilization-embryo transfer were examined after 3 and 6 days in culture. G-L cells from follicles that contained an oocyte that fertilized in vitro were compared with G-L cells from follicles that contained an oocyte that did not fertilize in vitro. Spent culture media was assayed for progesterone at days 3 and 6 of culture and luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor content of G-L cells was determined at day 6. G-L cell cultures from follicles that contained an oocyte that fertilized in vitro produced significantly more progesterone over 3 and 6 days of culture than those obtained from follicles in which the oocyte did not fertilize. Furthermore, LH/hCG receptor content after 6 days was significantly higher in G-L cells obtained from follicles with fertilized oocytes compared with follicles with unfertilized oocytes. Increased progesterone output and LH/hCG receptor acquisition demonstrate more maturation or "luteinization" by G-L cells aspirated from individual follicles that contain oocytes that fertilized in vitro.

Follicular fluid transferrin levels in preovulatory human follicles

There is transferrin-like protein present in the follicular fluid of stimulated ovarian cycles. The transferrin concentration correlates with the follicular morphologic maturity and steroidogenesis, varies among follicles, and often exceeds serum concentrations. An intermediate range of transferrin concentration is associated with the highest likelihood of oocyte fertilization in vitro. The biological significance of these observations may relate to an optimum degree of follicle maturation.

Inhibin--a non-steroidal regulator of pituitary follicle stimulating hormone

Inhibin is a gonadal glycoprotein produced by the granulosa and Sertoli cell under the influence of FSH and acts to specifically suppress pituitary FSH secretion. Recently, ovarian inhibin has been purified from several species and its amino acid sequence deduced using cloning techniques. Inhibin consists of two disulphide-linked heterologous subunits of which the smaller may exist in two different forms accounting for two different forms of inhibin in humans and pigs. Heterogeneity of inhibin also exists as a result of proteolytic processing of the molecule during its passage into the circulation. Significant homology exists between the subunits of inhibin and the dimeric peptides TGF-beta and Mullerian inhibitory substance (MIS), suggesting they are all derived from a common ancestral gene. Furthermore, dimers of the smaller subunit of inhibin (FSH-releasing protein (FRP) or activin) have now been found in follicular fluid (FF) and, along with TGF-beta, shown to be potent and specific stimulators of FSH secretion. These proteins may be involved in controlling FSH by another as yet unknown pathway and may prove to be the FSH-releasing factor, analogous to LHRH, which has been postulated to exist for some years. Inhibin can no longer be simply considered as an isolated FSH-suppressing protein. The physiological significance and relationship between inhibin and its related proteins represent one of the most challenging and interesting areas in reproductive endocrinology. Further studies, particularly with the development and use of sensitive assays for both the FSH releasing hormone and inhibin will clarify their role in reproduction and their usefulness in monitoring or treating fertility.

Paracrine regulation of follicular maturation in primates

Taken together, the studies reviewed here suggest that although gonadotropins are necessary for follicular growth, they are insufficient by themselves to explain the dynamics of folliculogenesis. Indeed, the role of gonadotropins in follicular maturation must necessarily be permissive: that is LH and FSH initiate a synchronized cascade of follicular events directly mediated by paracrine and autocrine factors.

Protein electrophoretic patterns of bovine and porcine ovarian follicular fluid

Sodium Dodecyl Sulphate polyacrylamide electrophoresis (SDS-PAGE) was used to reveal changes in the protein pattern of porcine and bovine ovarian follicular fluid at different maturational stages. Separate pools were made of follicles with a diameter of 1-2, 3-4, 5-6, 7-8, 9-10 and greater than 11 mm excluding hemorrhagic and cystic follicles. Prior to electrophoresis, estradiol-17 beta and androstenedione were analyzed to define the atresic or healthy state of the follicular. Glucose and total protein content of follicles fluid were determined to assess follicular metabolism. Densitometric analysis of both pig and cow follicular fluids from 3-4 mm follicles revealed a distinct band which was absent in other follicle sizes. On the other hand the protein pattern of follicular fluid of cow and pig showed differences in zones of molecular weight higher than 150,000 and lower than 30,000 dalton. This study suggests the possible existence of a common protein to both species which determines the follicle destiny towards ovulation or atresia.

Regulators of steroid secretion and inhibin activity in human ovarian follicular fluid

Inhibin activity from human follicular fluid was purified by successive chromatographies on Sephadex G-50, DEAE-Biogel A and orange A dye matrix. Inhibin activity was associated only with the protein(s) that bound to orange A (OrA-2). Daily injection of OrA-2, 1 h prior to hMG into 10-day-old female rats for 4 days caused a significant inhibition of hMG-induced estradiol secretion. In vitro, OrA-2 dose-dependently inhibited the amounts of estradiol secreted by porcine granulosa cells during a 3-h incubation. Orange A-unbound proteins, on the other hand, induced a dose-dependent increase in estradiol as well as progesterone secretion by porcine granulosa cells in vitro. Separation of stimulator from the inhibitor by orange A chromatography led to an increase in the relative inhibin activity (25-50-fold) as well as aromatisation-suppressing activity (60-fold). The results indicate a possible local action of hFF inhibin to regulate aromatisation activity.

Induction of ovulation with purified urinary follicle-stimulating hormone in patients with polycystic ovarian syndrome

Purified urinary follicle-stimulating hormone was used to induce ovulation in 18 patients with polycystic ovarian syndrome. Each ampule contained 75 IU of follicle-stimulating hormone and less than 0.11 IU of luteinizing hormone. Initial doses were 150 to 225 IU/day, later increased to a maximum of 375 IU, according to daily clinical controls and estradiol values. After 12 to 16 days, follicle-stimulating hormone treatment was suspended. Within 36 to 48 hours each patient received 5000 or 10,000 IU of human chorionic gonadotropin, rarely more. Ovulation occurred in 39 of 43 treatment cycles and hyperstimulation in nine. Seven patients had normal pregnancies with viable fetuses, including one pair of twins. Two had abortions. Analysis of the endocrine situation during therapy does not permit either pregnancy or hyperstimulation to be predicted. However, hyperstimulation is frequently accompanied by endogenous luteinizing hormone peaks and greater estradiol increases during the final phase of induction. Purified follicle-stimulating hormone has thus demonstrated its validity in inducing ovulation in patients with polycystic ovarian syndrome, apparently with equal or lower risks of hyperstimulation than with other gonadotropin preparations.

Demonstration of a gradient in inhibin activity, estrogen, progesterone, and delta 4-androstenedione in follicular fluid, ovarian vein blood, and peripheral blood of normal women

Ovarian vein serum from 3 subjects during the late follicular phase of the menstrual cycle had detectable inhibin activity, whereas ovarian vein serum of 12 other subjects during the early follicular phase and luteal phase had no detectable inhibin activity in a rat anterior pituitary cell culture assay. Subjects having detectable inhibin activity (102 +/- 47 U/100 microliters) had 1257 +/- 582 U/100 microliters inhibin activity in FF, whereas subjects having no detectable inhibin activity had FF levels of 711 +/- 203 U/100 microliters of inhibin activity. Estrogen levels of FF and ovarian vein serum of the group having detectable inhibin activity in ovarian vein serum were 282 +/- 239 ng/ml and 4.8 +/- 1.77 ng/ml, respectively. The estrogen content of FF and ovarian vein blood of the group having nondetectable inhibin activity in ovarian vein blood was 127 +/0 45 ng/ml and 3.03 +/- 0.6 ng/ml, respectively.

Follicular fluid inhibin activity and steroid levels in ovarian tissue obtained at autopsy from human infants from 18 to 200 days of age

The ovaries of 25 human infants from 18 to 200 days of age were obtained at autopsy, and their follicular fluid was subjected to measurement of inhibin activity, estrogen, progesterone, androstenedione, and testosterone. Significant inhibin activity was present in all samples of follicular fluid (charcoal-treated) (138 +/- 19 U/10 microliter follicular fluid; 10,545 +/- 2758 U/ovary). There was a tendency for greater inhibin activity, follicular volume, and estrogen in infants from 18 to 59 days than in older infants. There was a significant positive correlation between follicular fluid volume, estrogen, and androstenedione, compared with follicular fluid inhibin content per ovary. It is possible that elevated serum follicle-stimulating hormone and luteinizing hormone observed early in life stimulates follicle growth, inhibin, and estrogen production. As a result of elevated inhibin and estrogen, the gonadotropins may be inhibited, which may cause a decline in follicular activity after 4 to 6 months.

Follicle-stimulating hormone increases ovarian vein nonsteroidal factors with gonadotropin-inhibiting activity

Normally cycling monkeys were treated with 50 IU/day of "pure" follicle-stimulating hormone (FSH) on days 1 through 11 of the menstrual cycle. Ovarian venous serum (OVS) was collected on day 10; then all right ovarian follicles were aspirated. On day 11, OVS was collected again. Gonadotropin-inhibiting activity was determined in each sample by measuring the suppression of gonadotropin secretion by rat anterior pituitary cells in culture. OVS obtained on day 10 suppressed basal FSH secretion by approximately 45% and luteinizing hormone-releasing hormone stimulated luteinizing hormone secretion by approximately 50% (P less than 0.05, versus castrate serum). On day 11, OVS from the left ovary continued to suppress gonadotropin secretion, whereas OVS from the right ovary demonstrated significantly less gonadotropin-inhibiting activity. These findings demonstrate that exogenous FSH increases OVS concentrations of a nonsteroidal ovarian factor(s) with gonadotropin-inhibiting activity.

Stimulatory effects of follicle-stimulating hormone and luteinizing hormone upon secretion of progesterone and inhibin activity by cultured infant human ovarian granulosa cells

Ovarian tissue obtained from three human infants (60, 120, and 210 days of age) was separated into cell types and cultured. Granulosa cells from two of three subjects were viable and grew in culture. The cells had the potential to secrete low levels of progesterone and responded to luteinizing hormone and follicle-stimulating hormone added in culture with greatly enhanced ability to secrete progesterone. Granulosa cells could also secrete inhibin activity in culture and responded to luteinizing hormone and follicle-stimulating hormone with enhanced inhibin secretion. The granulosa cells also had the potential to secrete estrogen in the presence of testosterone. Serum levels of gonadotropin in the human infant are elevated for a period between 1 and 4 months; yet only follicular growth, not luteinization, occurs. It can be concluded that infant human granulosa cells, like adult human granulosa cells, have the potential of responding in vitro to gonadotropin.

Inhibin activity and steroid hormone levels in ovarian extracts and ovarian vein plasma of female monkeys during postnatal development

Inhibin activity, follicle-stimulating hormone (FSH)-suppressing substance, estrogen, progesterone, and androstenedione were measured in charcoal-treated ovarian tissue and ovarian venous and peripheral blood of eight rhesus monkeys ranging from 12 to 48 months of age. All of the monkeys demonstrated inhibin activity in ovarian tissue, which, if expressed per milligram protein, was relatively constant throughout development. However, if the activity was expressed per ovary, the amount of ovarian FSH-suppressing substance increased between 26 and 48 months; it was present in detectable amounts in ovarian venous blood only in one 26-month-old monkey. Detectable levels of estrogen were present in ovarian venous blood of the 26-month-old and the 48-month-old monkeys but not in the younger monkeys. It is possible that the secretion of inhibin activity may be in part responsible for low levels of serum FSH observed prior to puberty, because it has been observed by others that bilateral ovariectomy in the prepubertal monkey can result in a rise in FSH and that administration of charcoal-treated ovarian follicular fluid can suppress serum FSH in castrated prepubertal and adult rhesus monkeys.

Correlation of inhibin and follicle regulatory protein activities with follicular fluid steroid levels in anovulatory patients

Follicular fluid was obtained from anovulatory patients (n = 12), stimulated with human menopausal gonadotropin, clomiphene, and human chorionic gonadotropin to evaluate the relative responses of inhibin, follicle regulatory protein, and steroid levels in follicles from ovaries requiring exogenous stimulation for follicular development. Follicular fluid concentrations of estradiol, progesterone, androstenedione, testosterone, dihydrotestosterone, and 3 alpha-androstenediol were determined by radioimmunoassay. Follicular fluid inhibin activity was determined by suppression of rat pituicyte follicle-stimulating hormone, and follicle regulatory protein activity was determined by suppression of porcine granulosa cell aromatase. The mean level of steroids were progesterone (7529 +/- 1601 ng/ml), estradiol (1082 +/- 158 ng/ml), androstenedione (15.2 +/- 3.17 ng/ml), 3 alpha-androstenediol (0.90 +/- 0.13 ng/ml), testosterone (2.23 +/- 33 ng/ml), and dihydrotestosterone (0.77 +/- 0.11 ng/ml). Follicle regulatory protein activity was 16.6% +/- 4.3% and mean inhibin level was 62.9 +/- 7.52 U. These results are in contrast to reports of follicular fluid steroid levels from normal ovulatory patients treated with exogenous gonadotropin. Although altered levels of hormones were present within these follicles, they clearly were not atretic, as evidenced by elevated estradiol levels and estradiol/androstenedione ratios. Alterations in the normal follicular response to pharmacologic gonadotropin stimulation in the follicles of anovulatory women suggest the presence of granulosa cell dysynchrony .

Porcine inhibin: initial fractionation as a high molecular weight complex

A high molecular weight complex or aggregate of inhibition was obtained by chromatography of porcine follicular fluid in Fractogel TSK65F. Recovery of activity was good (usually 80-100%), but only 30-60% was recovered as a high molecular weight complex (greater than 160,000) free of albumin and gamma globulin (the two major proteins in follicular fluid). The balance of the activity was distributed in the gamma globulin-albumin region of the chromatogram (i.e., 160,000 down to 65,000 daltons). Distribution in this region of the chromatogram in part reflected the prior processing of the sample (e.g., it was augmented by ethanol or acetone precipitation prior to chromatography). The utility of Fractogel chromatography lies in its ability to resolve a large portion of the inhibin activity from the major proteins (albumin and gamma globulin), plus an efficient recovery of activity. Maximum purification on the Fractogel chromatograms was approximately 20-fold. This product and the other Fractogel fractions were tested for protease activity by a sensitive slab gel procedure. All fractions contained detectable protease activity that could potentially affect inhibin activity during further fractionations. This was shown with a protease fraction isolated from porcine follicular fluid by affinity chromatography. When added to a partially purified inhibin preparation, this protease fraction destroyed 77% of the inhibin activity.

Decline of follicular oocyte maturation inhibitor coincident with maturation and achievement of fertilizability of oocytes recovered at midcycle of gonadotropin-treated women

To examine whether a decline in follicular oocyte maturation inhibitor (OMI) is associated with attainment of oocyte maturation and fertilizability, OMI was measured in follicular fluid (FF) of 39 follicles of 20 normal women given human menopausal gonadotrophin and human chorionic gonadotrophin to induce follicular growth and maturation. Oocytes were aspirated per laparoscope, the fluid was saved, and the egg was observed, incubated, and inseminated with the husband's sperm. Concepti that developed to the 4- to 8-cell stage were transferred to the uterus and the women were followed for pregnancy. OMI activity in each FF was measured by using cultured cumulus-enclosed porcine oocytes (30-40 oocytes per FF sample). Estrogen, progesterone, oocytes (30-40 oocytes per FF sample). Estrogen, progesterone, and delta 4-androstenedione were measured in FF by radioimmunoassay. The FF of 13 preovulatory follicles yielding oocytes that were mature and fertilizable had significantly less OMI activity (mean +/- SEM) (0.58 +/- 0.10 unit/ml) compared to follicles yielding immature oocytes (2.8 +/- 0.56 units/ml; n = 9), atretic oocytes (5.5 +/- 2.5 units/ml; n = 7), or preovulatory oocytes with fractured zonae (1.9 +/- 0.63 units/ml; n = 7). The estrogen concentration (mean +/- SEM) of preovulatory follicles yielding mature fertilizable eggs or mature eggs with fractured zonae was greater (396 +/- 34 ng/ml; n = 20) compared to follicles yielding immature or atretic eggs (203 +/- 59 ng/ml; n = 9 and 97 +/- 47 ng/ml; n = 7, respectively; P less than 0.05). Progesterone concentration (mean +/- SEM; ng/ml) of FF was generally elevated in all preovulatory follicles (635 +/- 53) compared to immature or atretic follicles (230 +/- 64 and 76 +/- 17, respectively; P less than 0.05). It may be concluded that in normal follicle maturation there is a decline in OMI in the follicle containing an oocyte that becomes mature and fertilizable. There is also an increase in estrogen, progesterone, and follicle size. It is also possible to have an abnormal follicle maturation when there is an increase in size as well as FF, estrogen, and progesterone, but withut a decline in OMI--a situation which can lead to production of a nonfertilizable oocyte.

Reversal of persistent anovulation in polycystic ovarian disease by administration of chronic low-dose follicle-stimulating hormone

Low doses of follicle-stimulating hormone (FSH) were administered once daily to two consecutive patients with polycystic ovarian disease (PCOD) for therapy of infertility. Serial blood samples were obtained for gonadotropins and ovarian steroid determinations during the period of FSH administration. Exogenous FSH resulted in an initial and concomitant decrease in serum androstenedione (A), estrone (E1), and luteinizing hormone (LH), with an increase in estradiol (E2) and FSH. Subsequent changes in the above-mentioned hormonal levels were typical of a normal ovulatory cycle, with the exception of FSH, which continued to rise in the second half of the follicular phase. This was attributed to the exogenous administration of FSH. Both patients became pregnant in their first induced ovulatory cycle by administration of chronic low-dose FSH. These preliminary data demonstrate (1) a correction of the biochemical imbalance characteristic of PCOD, (2) successful ovulation induction, and (3) restoration of fertility in PCOD treated with chronic low-dose FSH.

Actions of hormones and other factors upon oocyte maturation

Oocyte maturation is controlled by a combination of hormonal and local follicular factors. Osmolarity, pH, and perhaps Ca2+ concentration of the surrounding medium are also important. Follicular fluid contains a low molecular weight OMI which acts to keep the oocyte from maturing. Luteinizing hormone added to cultured cumulus enclosed porcine oocytes can reverse the inhibitory action of OMI. The level of OMI in the follicular fluid appears to decrease as the follicle matures. Addition of FSH and prolactin to cultured granulosa cells stimulates OMI secretin whereas addition of testosterone or dihydrotesterone brings about a decrease in OMI secretion. Elevated LH in vivo may bring about oocyte maturation before ovulation by (a) an antagonist action on OMI; (b) stimulating the synthesis of testosterone by theca cells and thus inhibiting the synthesis of OMI by granulosa cells; and (c) action on the granulosa cells to promote luteinization which may also cause a decrease in OMI synthesis. The hastened oocyte maturation associated with follicular atresia could be due to a decline in OMI due to granulosa cell death and/or elevated follicular androgens.