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N R Moudgal

Publications and source records attributed to N R Moudgal.

At least 37 records · Page 2Linked to original sources
PubMed1992

Effect of 80 kDa protein of porcine follicular fluid on gonadotropin stimulated progesterone production in rat granulosa cells in vitro.

We reported the presence of a 80 kDa polypeptide in porcine follicular fluid that inhibited the binding of 125I-radiolabelled hFSH as well as hCG to the rat ovarian gonadotropin receptors. In the present study, the biological activity of the receptor binding inhibitor is determined using an in vitro bioassay procedure. Granulosa cells isolated from PMSG primed immature rat ovaries respond to exogenously added gonadotropins in terms of progesterone production. Addition of fractions containing the gonadotropin receptor binding inhibitory activity inhibited progesterone production stimulated by the gonadotropins in a dose-dependent fashion. The receptor binding inhibitory activity was also capable of inhibiting progesterone production stimulated by PMSG, which has both FSH- and LH-like activities in rats. In contrast, progesterone production stimulated by dbcAMP was not inhibited by the receptor binding inhibitor. This result indicates that the site of action of the inhibitor is proximal to the formation of the cAMP. The above observations point out to a possible role for this factor in modulating gonadotropin activity at the ovarian level.

Animals↗
PubMed1992

Long-term contraceptive efficacy of vaccine of ovine follicle-stimulating hormone in male bonnet monkeys (Macaca radiata).

A group of ten healthy fertile adult male bonnet monkeys were actively immunized using procedures acceptable for human use with pure follicle-stimulating hormone (oFSH) isolated from sheep pituitaries. The vaccine elicited an immunogenic response in all ten monkeys; the antibody-binding capacity, determined by Scatchard analysis, varied from 3 to 18 micrograms oFSH ml-1, the binding affinity ranging from 0.13 to 2.0 x 10(10) mol-1. A substantial population of antibodies against oFSH crossreacted with 125I-labelled human (h) FSH, used here as a representative ligand of primate FSH. The bioneutralization activity of the antisera assessed by a specific bioassay in vitro, when the antibody titre was high, was 6.9 +/- 0.18 micrograms hFSH ml-1. Immunization for 4.7-5.7 years did not affect the health and libido of the animals. Concentration of testosterone in serum remained normal throughout the study, but, within 150 days of immunization, there was a marked decrease (75-100%) in the number of spermatozoa in seminal ejaculates. Oligospermic status interspersed with azoospermia was maintained by periodic boosting. The fertility of these animals was monitored between 6 months and 2 years after primary immunization. All the ten animals proved infertile in repeated mating experiments with females of proven fertility. After stopping booster injections, nine of ten animals regained fertility, but the time taken for this depended upon the rate of decline of antibody titres. Re-boosting these monkeys with 100 micrograms oFSH after confirming that recovery had occurred revealed prompt increases in antibody titres followed once again by onset of oligo-azoospermia and infertility, underscoring the specificity of immunization effect. The immunized monkeys, apart from being acutely oligospermic, ejaculated spermatozoa that were markedly deficient in key acrosomal enzymes, such as acrosin and hyaluronidase, and motility as well as in their ability to penetrate a gel in vitro, suggesting that the infertility observed was due to gross reductions in the numbers of spermatozoa that could effectively interact with the oocyte and cause successful fertilization.

Acrosin↗
PubMed1992

Ability of deglycosylated human chorionic gonadotropin (dghCG) to block luteal function and establishment of pregnancy in bonnet monkeys (Macaca radiata).

The ability of deglycosylated hCG (dghCG) prepared by deglycosylation of a clinical hCG (3000 IU/mg) preparation, to block luteal function during regular cycles as well as luteal rescue in simulated and mated cycles of female bonnet monkeys (M. radiata) has been evaluated. The cycle length (C:28 vs E:24 days) and the total progesterone produced during the luteal phase was significantly reduced (by 45%, P < .05) by injecting 450 micrograms of dghCG/day (in split doses) on days 18, 19, and 20 of cycle. At the doses tested the dghCG used did not exhibit any agonistic activity in the female monkey. In a second experiment injection of 200 micrograms of dghCG/day on days 18-20 of cycle blocked the normal response of the luteal tissue to exogenous hCG (10 micrograms of a 12,000 IU/mg preparation) injected on day 23 of cycle. In a third experiment no pregnancies occurred when a group of 5 animals were injected dghCG (450 micrograms dghCG/day) on days 18-21 of their mated cycle. Animals chosen for this study were proven fertile regularly cycling monkeys and these were cohabited with males between days 9 and 14 of cycle. Each of the monkeys was exposed to 3 consecutive treatment cycles. During post-treatment phase 2 out of 3 monkeys exposed to males became pregnant. The study clearly demonstrates that it is possible to block normal luteal function as well as luteal rescue of the female monkey by using dghCG in the right dose and mode.

Animals↗
PubMed1992

The effect of malathion, an organophosphate, on the plasma FSH, 17 beta-estradiol and progesterone concentrations and acetylcholinesterase activity and conception in dairy cattle.

The effect of malathion on jugular plasma concentrations of follicle-stimulating hormone (FSH), estradiol (E2), progesterone (P4) and acetylcholinesterase (AchE) on conception in dairy cattle during a cloprostenol (prostaglandin F2 alpha analogue, PG)-induced estrus was studied. Malathion (1 mg/kg, intraruminally) given at the onset of estrus (48 h after PG) did not alter the plasma FSH or E2 concentrations but significantly (P less than 0.05) inhibited plasma P4 concentration. The mean P4 concentration in the malathion-treated group on days 8 and 12 were 0.8 +/- 0.4 and 1.0 +/- 0.5 ng/ml, as compared to 2.6 +/- 0.0 and 2.4 +/- 0.3 ng/ml in the control group. There was a nonsignificant (P greater than 0.05) inhibition of plasma AchE activity in malathion-treated cattle. Conception was 16.6% in malathion-treated cows and 50% in controls. Inhibition of progesterone secretion and poor conception occurred after the single intraruminal dose of malathion at the onset of estrus.

Acetylcholinesterase↗
PubMed1990

Two simple and rapid methods to detect monoclonal antibodies with identical epitope specificities in a large population of monoclonal antibodies.

Two novel and simple methods have been developed for detecting monoclonal antibodies (MAbs) with identical epitope specificities from a large population of MAbs against human chorionic gonadotropin (hCG). The first method was based on the observation that following radioiodination many molecules of an antigen are altered in such a manner that they cannot be recognized by MAbs. The proportion of radiolabelled antigen (Bmax) able to bind to a MAb was characteristic of that MAb and MAbs having identical specificities showed identical Bmax values. Using this principle it was possible to identify MAbs having identical epitope specificities within a large population of MAbs against hCG. In the second method one test MAb was immobilized on a plastic surface through an immunochemical bridge. This MAb was then incubated with 125I-hCG previously complexed with a second MAb. Such a complex could bind to the solid phase MAb only if the two MAbs were not identical. The results obtained with both methods were concordant. With such methods it is possible to identify MAbs with identical epitope specificities immediately after the initial screening of the fusion. These methods do not require subcloning, ascites production, or the purification and iodination of large number of MAbs.

Animals↗
PubMed1990

Conformation of the alpha-subunit of glycoprotein hormones: a study using polyclonal and monoclonal antibodies.

The conformation of the common alpha-subunit of human glycoprotein hormones, luteinizing hormone (hLH), follicle-stimulating hormone (hFSH), thyroid-stimulating hormone (hTSH) and chorionic gonadotropin (hCG) was probed using a highly specific polyclonal antiserum against the alpha-subunit of hCG and several monoclonal antibodies (MAbs) produced against hCG which recognized the alpha-subunit in free and combined form. The alpha-subunit was found to be conformationally altered (compared to its conformation in the isolated state) when it was in combination with various beta-subunits as indicated by shifts in the displacement curves of binding of [125I]hCG alpha to the polyclonal antiserum. The extent of the change was dependent on the beta-subunit present with minimum change being observed with hLH beta, intermediate with hCG beta and maximum change with hFSH and TSH beta-subunits. However, the affinity constants of this antiserum for all four hormones were nearly similar. Further, it was also found that binding of any one of the glycoprotein hormones to this antibody could be completely inhibited by any other hormone suggesting that the conformation of the alpha-subunit in all the four hormones is probably very similar. This was further investigated using five hCG MAbs capable of recognizing the alpha-subunit, but with different epitope specificities. All these MAbs could recognize all the four hormones suggesting the presence of the epitopes in these proteins. These epitopes were conformation specific since the MAbs did not bind reduced and carboxymethylated alpha-subunit. Displacement analysis using [125I]hCG as the tracer showed that two epitopes have nearly the same conformation in all the four hormones, while two were partially modified depending on the beta-subunit present. Based on these results, it is concluded that the alpha-subunit of glycoprotein hormones has nearly the same conformation, though subtle differences do exist.

Antibodies, Monoclonal↗
PubMed1990

Luteal-phase defect induced by deprivation of FSH at a specific period of the follicular phase prevents pregnancy in the bonnet monkey (Macaca radiata).

Female bonnet monkeys were injected i.v. with 25 microliters antiserum to FSH on Days 5, 6 or 7 of the cycle: the length of the luteal phase was shortened but there was no alteration in cycle length. Proven fertile females (N = 6) were caged throughout the period of the experiment (6 cycles) with proven fertile males and treated with 25 microliters FSH antiserum on Day 7 of each of 3 successive cycles. Out of 18 cycle exposures during the treatment phase, 17 were ovulatory, but no pregnancies occurred. In the post-treatment phase, 5 monkeys became pregnant within 3 cycle exposures. These results show that it is possible to render female monkeys infertile by creating luteal insufficiency and this can be achieved repeatedly in a reproducible manner by depriving the cyclic females of FSH support on Day 7 of consecutive cycles.

Animals↗
PubMed1990

DNA flow-cytometric analysis of testicular germ cell populations of the bonnet monkey (Macaca radiata) as a function of sexual maturity.

Testicular germ cell populations of biopsies from 32 male bonnet monkeys in 5 different age groups were quantitated in a flow cytometer after labelling of germ cell DNA with the specific fluorochrome, 4,6-diamidino phenyl indole. The 5 quantifiable populations were spermatogonia (2C), preleptotene spermatocytes (S phase), primary spermatocytes (4C), round spermatids (1C) and elongate spermatids (HC). The seminiferous tubules of immature 3-4-year-old monkey had only Sertoli cells and spermatogonia (2C). At 5-6 years, germ cells in S-phase (9.5%), 4C (11.1%), 1C (41.8%) and HC (17.1%) stages of maturation appeared for the first time but at 7-8 years of age and beyond all cell types except HC decreased while 1C remained relatively constant. Histometric analysis correlated well with the flow-cytometric data. The decrease in cells of 2C, S-phase and 4C stages was associated with an increase in mitotic index, signifying acceleration in the kinetics of germ cell transformation into subsequent cell types. The total turnover in cell transformation (1C:2C) was significantly (P less than 0.01) increased at and beyond 7-8 years. Maximum transition from 2C to 4C occurred at 5-6 years (4C:2C ratio 0.8 at 5-6 years and 0.6 at 7-8 years). The ratio HC:1C (kinetics of cell transformation during spermiogenesis) attained near total efficiency only by 10 years of age (1.08 at 10-14 years; 0.9 at 18-20 years). Also, the cell associations within the seminiferous tubules of monkeys greater than or equal to 10 years of age were better defined than those of younger animals. The changes in germ cell ratios correlated well with alterations in testicular volume, sperm numbers in the ejaculate and surges of testosterone and increments in FSH in the serum, characteristic of development of sexual maturity. It is apparent from this study that DNA flow cytometry of testicular germ cell populations reveals subtle changes in spermatogenic status of bonnet monkeys with a high degree of sensitivity.

Animals↗
PubMed1989

Studies on follicular atresia: role of gonadotropins and gonadal steroids in regulating cathepsin-D activity of preovulatory follicles in the rat.

Preovulatory follicular atresia was studied using pregnant mare serum gonadotropin (PMSG)-primed rats (15 IU/rat) which were deprived of hormonal support either by allowing the metabolic clearance of the PMSG or by injecting a specific PMSG antiserum (PMSG a/s). Atresia was monitored by an increase in lysosomal cathepsin-D activity and a decrease in the receptor activity of the granulosa cells (GC) isolated from the preovulatory follicles. It was shown that the increase in lysosomal activity and the decrease in receptor activity seen at 96 h after PMSG (or PMSG plus PMSG a/s) could be arrested both by follicle stimulating hormone (FSH) and luteinizing hormone (LH). Injection of cyanoketone or clomiphene citrate together with FSH/LH prevented this 'rescue' suggesting a role for estrogens in the regulation of atresia. Although the administration of estradiol-17 beta (20 micrograms/rat) together with PMSG a/s could show a 'rescue effect' in terms of reduction in cathepsin-D activity the gonadotropin receptor activities of these granulosa cells were not restored. The injection of dihydrotestosterone (DHT) to 48 h PMSG-primed rats induced atresia as noted by an increase in cathepsin-D activity. However, the exogenous administration of FSH along with DHT prevented this atretic effect suggesting that DHT is not having a direct effect on atresia. Determination of androgen: estrogen content of the granulosa cells and an analysis of the individual profile of androgen and estrogen revealed that the increase in cathepsin-D activity could be correlated only with the decrease in GC estrogen content. This along with the observation that GC showed a loss of estrogen synthesis well before the increase in cathepsin-D activity strongly points out that the lack of estrogen rather than an increase in androgen is the principle factor responsible for the atresia of preovulatory follicles in the rat.

Androgens↗
PubMed1989

Isolation and characterization of a gonadotropin receptor binding inhibitor from porcine follicular fluid.

The presence of a gonadotropin receptor binding inhibitor in pooled porcine follicular fluid has been demonstrated. Porcine follicular fluid fractionation on DE-32 at near neutral pH, followed by a cation exchange chromatography on SPC-50 and Cibacron blue affinity chromatography, yielded a partially purified gonadotropin receptor binding inhibitor (GI-4). The partially purified GI binding inhibitor inhibited the binding of both 125I labelled hFSH and hCG to rat ovarian receptor preparation. SDS electrophoresis of radioiodinated partially purified GI followed by autoradiography made it possible to identify the binding component as a protein of molecular weight of 80,000. Subjecting 125I labelled GI-4 to chromatography on Sephadex G-100 helped obtain a homogeneous material, GI-5. The 125I labelled GI-5 exhibited in its binding to ovarian membrane preparations characteristics typical of a ligand-receptor interaction such as saturability, sensitivity to reaction conditions as time, ligand and receptor concentrations and finally displaceability by unlabelled inhibitor as well as FSH and hCG in a dose dependent manner. This material could bind ovarian receptors for both FSH and LH, its binding being inhibited by added FSH or hCG in a dose dependent manner.

Animals↗
PubMed1989

Effect of FSH deprivation at specific times on follicular maturation in the bonnet monkey (Macaca radiata).

Cyclic monkeys were deprived of FSH for specific periods on different days of the follicular phase by injecting them with minimal doses of an FSH antiserum characterized for specificity and bioneutralizing ability. The effect of the antiserum on follicular maturation was assessed by determining (a) serum oestrogen concentrations through the midcycle period, (b) serum progesterone concentrations as an index of ovulation and luteal function, (c) laparoscopic examination of the surface of the ovary when necessary, and (d) overall cycle length. While antiserum injection on Day 5 of the cycle caused delay in the oestrogen surge from Days 9 to 11, injection on Day 6 led to the occurrence of two oestrogen surges, on Days 9 and 14. Laparoscopic examination showed that the earlier follicle had disappeared and a new follicle had appeared by Day 14. Antiserum injection on Day 7 of the cycle arrested further growth of the maturing follicle, but a new follicle appeared 9 days later, as indicated by a surge of oestrogen on Day 16. Injection of antiserum beyond Day 7 had no effect on follicular development, ovulation and luteal function. These observations suggest that the mature follicle becomes relatively independent of FSH support about 48 h before ovulation and this event could be a marker for follicular dominance.

Animals↗
PubMed1989

Biochemical and histological validation of a model to study follicular atresia in rats.

A model system to study the biochemical mechanism of follicular atresia in rats [Dhanasekaran et al. 1983] was characterized using histological and biochemical correlates. PMSG and PMSG antiserum (a/s) was used to induce the follicular growth and atresia of preovulatory follicles. Ovarian histology during these PMSG and PMSG a/s - treatment periods was recorded under a light microscope. An analysis of lysosomal enzyme cathepsin-D activity of granulosa cells (GC) from similarly treated ovaries showed that there was a reduction in cathepsin-D activity during the histologically observable follicular growth; and there was an increase in cathepsin-D activity during atresia. The increase in cathepsin-D activity also showed an inverse correlation with the general anabolic activity of the GC as demonstrated here, by a reduction in 3H-leucine incorporation activity. An analysis of other gonadotropin-responsive cells for the presence of such hormone sensitive lysosomal machinery, only corpora lutea (CL) and GC showed in the cathepsin-D activity upon treatment with 15 IU of PMSG. The results suggests the existence of a common gonadotropin regulated lysosomal machinery in cells endowed with a degenerative pathway of "programmed cell death". More importantly the results establish the validity of using lysosomal enzyme cathepsin-D as a biochemical marker, for hitherto morphologically and endocrinologically studied cellular degenerative process of follicular atresia.

Animals↗
PubMed1988

Gonadotropin regulation of rat ovarian lysosomes: existence of a hormone specific dual control mechanism.

Gonadotropic hormones PMSG (15 IU/rat), FSH (3 micrograms/rat), LH (9 micrograms/rat) and hCG (3 micrograms/rat) were shown to decrease the free cytosolic lysosomal enzymes during the acute phase of hormone action in rat ovaries. When isolated cells from such rats were analyzed for the cathepsin-D activity, the granulosa cells of the ovary showed a reduction in the free as well as in the total lysosomal enzyme activities in response to FSH/PMSG; the stromal and thecal compartment of the ovary showed a reduction only in the free activity in response to hCG/PMSG. The results suggest the presence of two distinct, target cell specific, mechanisms by which the lysosomal activity of the ovary is regulated by gonadotropins.

Acid Phosphatase↗
PubMed1987

Use of tamoxifen, an antioestrogen, in establishing a need for oestrogen in early pregnancy in the bonnet monkey (Macaca radiata).

Administration of tamoxifen orally (3 mg/kg/day) during the post-ovulatory period from Days 16 to 20 or from Days 18 to 30 of female bonnet monkeys mated between Days 9 and 14 of the cycle resulted in inhibition of pregnancy establishment in 90-100% of monkeys tested. The pregnancy establishment in control female monkeys after exposure to the male during one ovulatory cycle was 66%. The effect of tamoxifen was not due to interference with luteal function because there was no reduction in serum progesterone concentrations after drug treatment. Exogenously administered progesterone could not reverse the inhibitory effect of tamoxifen on pregnancy establishment. The effect of tamoxifen was dose-dependent. We suggest that tamoxifen could be developed as an effective post-ovulatory contraceptive for regulation of female fertility.

Animals↗
PubMed1986

Studies on follicular atresia: role of tropic hormone and steroids in regulating cathepsin-D activity of preantral follicles of the immature rat.

The ovary of the immature female rat is comprised of primary and medium-sized preantral follicles. Upon stimulation with FSH or PMSG, the cathepsin-D activity, a representative lysosomal enzyme of granulosa cells, is reduced by 50% (P less than 0.01). 17 beta-Estradiol at the doses tried was unable to mimic this effect. Blockade of steroidogenesis with cyanoketone also had no effect on the cathepsin-D activity of isolated granulosa cells. Dihydrotestosterone (DHT), however, at a dose of 1 mg/rat was able to inhibit PMSG's tropic action. It brought about an increase in cathepsin-D activity and reduction in steroidogenic activity of isolated granulosa cells. The atretogenic activity of DHT could be relieved by supplementation with exogenous FSH. DHT was observed to significantly reduce (P less than 0.01) endogenous FSH and LH levels within 12-18 h of its injection suggesting that its atretic effect was due to its action at the pituitary rather than the gonad. In addition to the above the ability of 15 IU of PMSG to reduce cathepsin-D activity of granulosa cells was also significantly reduced (P less than 0.01) if endogenous FSH was neutralized by a specific FSH antiserum. The present study suggests that as far as small and medium-sized primary and preantral follicles are concerned, FSH lack is the essential signal for onset of atresia.

Adrenal Cortex Hormones↗
PubMed1985

Effect of LHRH agonists and antagonists in male and female bonnet monkeys (Macaca radiata).

A few analogues of LHRH have been tested in the adult bonnet monkeys using change in serum testosterone following LHRH injection as a parameter of response to LHRH. Of the four analogues tested in male monkeys, Buserelin was found to be the most potent one in increasing serum testosterone levels. Injection of the LHRH antagonist at 1600 h resulted in the abolition of the characteristic nocturnal surge of testosterone observed in adult bonnet monkeys maintained under regulated light conditions. Following administration of LHRH a/s during early pregnancy, serum chorionic gonadotropin levels decreased though the course of pregnancy was not affected. These results suggest that bonnet monkey can be successfully employed to test LHRH analogues.

Animals↗
PubMed1985

On the immunogenicity of the beta subunit of ovine luteinizing hormone (oLH beta) and equine chorionic gonadotropin (eCG) in the chimpanzee (Pan troglodytes): effect of antiserum on monkey cycle and early pregnancy.

Antibody to ovine LH beta (oLH beta) subunit and equine chorionic gonadotropin (eCG) were produced in adult male chimpanzees and evaluated for cross reactivity with oLH, human chorionic gonadotropin (hCG) and eCG by in vitro and in vivo methods. Chimpanzee antiserum to eCG failed to cross-react with hCG, but antibody raised against oLH beta subunit effectively neutralized not only exogenously administered hCG but also endogenous pituitary LH and monkey (Macaca radiata) chorionic gonadotropin. Chimpanzee antiserum to oLH beta when administered early in pregnancy reduced progesterone levels and terminated gestation in bonnet monkeys. Our data suggest that active immunization of chimpanzee, an ape that is very close to human, with oLH beta subunit leads to production of antibodies that are likely to affect both normal cycle as well as pregnancy.

Animals↗