Young S. Moon

Enzyme inactivation and inhibition by Gossypol

SummaryThree lactate dehydrogenase isozymes and malate dehydrogenase purified from mouse tissues were inactivated with time by low concentration of gossypol. The degree of enzyme inactivation is both gossypoland enzyme-concentration-dependent. Under the same experimental conditions, lactate dehydrogenase-X and lactate dehydrogenase-5 were inactivated faster than lactate dehydrogenase-1. NADH was shown to partially protect the enzymes against inactivation by gossypol. The results of this study suggest that the enzymes are inactivated by the minor components in gossypol preparations. Isozymes of glutathione S-transferases were reversibly inhibited by gossypol. The inhibition of transferases by gossypol was shown to be competitive with respect to the 1-chloro-2,4-dinitrobenzene. It is proposed that the male antifertility effect of gossypol may be related to the selective inactivation of sperm-specific lactate dehydrogenase-X.

The outcome of in vitro fertilization and embryo transfer in women with polycystic ovary syndrome failing to conceive after ovulation induction with exogenous gonadotropins

OBJECTIVE To assess the outcome of in vitro fertilization and embryo transfer (IVF-ET) in women with refractory polycystic ovarian syndrome (PCOS). DESIGN Retrospective case series with an age-matched control group. SETTING Ovulation induction and IVF programs in a tertiary referral center. PATIENTS AND INTERVENTIONS Nine patients with PCOS who failed standard ovulation induction treatment (clomiphene citrate plus greater than or equal to 6 ovulatory human menopausal gonadotropin [hMG] cycles) underwent 19 cycles of IVF-ET. Forty age-matched tubal factor patients who completed 40 cycles of IVF-ET served as a control group. OUTCOME MEASURES Demographic features and IVF-ET cycle characteristics were compared using Students t-test and Fishers exact test. RESULTS Cycles of IVF-ET in patients with PCOS were associated with higher estradiol levels (5,222 versus 4,009 pmol/L), lower hMG requirements (15.8 versus 19.6 vials), greater numbers of oocytes (7.6 versus 5.6), and lower fertilization rates (56% versus 75%) compared with tubal factor cycles (P less than 0.05). However, the number of embryos transferred (3.9 versus 4.0) and the clinical pregnancy rate per embryo transfer (24% versus 25%) did not differ significantly between the two groups. CONCLUSION These results suggest that conception failure after six or more ovulatory hMG cycles in patients with PCOS does not adversely affect subsequent IVF performance.

Relationship of gonadotropin-releasing hormone, danazol, and prostaglandin blockade to ovarian enlargement and ascites formation of the ovarian hyperstimulation syndrome in the rabbit

The effects of pharmacologic doses of gonadotropin-releasing hormone, danazol, and indomethacin on the clinical and endocrinologic features of the ovarian hyperstimulation syndrome were studied in the rabbit. The ovarian hyperstimulation syndrome was induced with Pergonal (75 IU of follicle-stimulating hormone and 75 IU of luteinizing hormone) and a follicle-stimulating hormone-dominant gonadotropin preparation (85 IU of follicle-stimulating hormone and 53 IU of luteinizing hormone). None of the three agents tested were effective in suppressing the ovarian enlargement and ascites formation in these animals. Ascites developed despite quite significant variations in plasma and intraovarian sex steroid hormone and intraovarian prostaglandin F levels induced by danazol and indomethacin. Ascites develops in hyperstimulated women in association with both follicular and luteal hyperstimulation. In contrast, the ascites response in the hyperstimulated rabbit develops in the presence of follicular hyperstimulation alone without a significant degree of luteal hyperstimulation.

Clinical, endocrinologic, and intraovarian prostaglandin F responses to H-1 receptor blockade in the ovarian hyperstimulation syndrome: studies in the rabbit model.

The effects of chlorpheniramine maleate, an H-1 receptor blocker, on clinical and endocrinologic features and intraovarian prostaglandin F (PGF) content were assessed in the rabbit model of the ovarian hyperstimulation syndrome. H-1 receptor blockade prevented ascites, attenuated ovarian enlargement (2.68 +/- 0.37 gm versus 4.15 +/- 0.056 gm; p less than 0.05), and augmented intraovarian PGF content (8.4 +/- 0.84 versus 3.95 +/- 1.12 pg/mg protein; p less than 0.05). Steroidogenesis was unaffected. In the control group, in which weights remained stable, animals with minimal ascites (scores less than or equal to 2; n = 4) were compared to other control animals with a greater accumulation of fluid (scores greater than or equal to 3; n = 4). The former also exhibited lower ovarian weights (2.94 +/- 0.41 versus 5.35 +/- 0.59 gm; p less than 0.05) and higher PGF ovarian content (6.05 +/- 1.56 versus 1.8 +/- 0.75 pg/mg of protein; p less than 0.05). This triad of minimal ascites, lower ovarian weights, and elevated intraovarian PGF seen both in treated animals and in inherently more resistant control animals did not appear to depend on changes in body weight. The conclusion reached was that H-1 receptor blockade prevented ascites, reduced ovarian enlargement, and augmented PGF content but did not affect steroidogenesis. This protective effect of chlorpheniramine may be mediated at least in part by prostaglandins.

Chromosome investigation in in vitro fertilization failure

PurposeA chromosomal complement of 227 human oocytes was studied to provide information on the frequency and type of chromosomal abnormalities in oocytes failing in vitro fertilization.ResultsNormal haploid chromosome complement was found in 54.6%; chromosomal abnormalities consisting of diploid sets were identified in 16.7% and aneuploidy was observed in 26%. Premature condensation of sperm chromosomes of the G1-phase was observed in 22.9% oocytes. Male infertility was correlated with an increase in the rate of aneuploidy when compared with tubal infertility. The rate of chromosome abnormalities for the oocytes recovered from women who had no fertilized oocytes was significantly higher compared to those with at least one oocyte fertilized.ConclusionA high frequency of chromosome abnormalities in unfertilized oocytes suggests that natural selection against chromosome abnormalities may occur even prior to fertilization.

Effect of prolactin in an experimental model of the ovarian hyperstimulation syndrome

In the rabbit model of the ovarian hyperstimulation syndrome, animals given ovine prolactin with human menopausal gonadotropins (hMGs), as compared to animals receiving hMGs alone, demonstrated an increase in the formation of ascitic fluid, a decrease in mean plasma estradiol, and an increase in the mean plasma progesterone concentrations. The ovarian estradiol and progesterone content reflected that of the peripheral blood. These data suggest that, under the conditions of these experiments, prolactin may play a role in the pathogenesis of ascites formation but not the ovarian enlargement observed in this syndrome. Although the plasma estradiol levels were lower and the progesterone levels were higher in the animals treated with prolactin and gonadotropins, this did not prevent the occurrence of ascites, a cardinal clinical sign of this gonadotropin-induced syndrome.

Investigation of effects of pregnant mare serum gonadotropin (PMSG) on the chromosomal complement of CD-1 mouse embryos

AbstractPurpose:The objective of this study was to examine the effect of superovulatory doses of gonadotropins on the frequency of chromosomal abnormalities of mouse embryos. Methods:Chromosome analysis of 8- to 16-cell stage mouse embryos and zygotes was performed by a cytogenetic method.Results:There was no significant effect of the pregnant mare serum gonadotropin (PMSG) dose on the level of aneuploidy and structural abnormalities from 8- to 16-cell-stage embryos among superovulated groups. However, a simple dose-response relationship between the PMSG dose and the incidence of polyploidy was observed, with the level of polyploidy rising from 2.9% with 10 IU PMSG to 10.5% with 15 IU PMSG. In zygote stage, the proportion of polyploid embryos also increased as the dose increased, from 1.9% in 5 IU to 6.7% in 15 IU PMSG. It was observed that the extra chromosomal set in polyploidy embryos originated by both fertilization of a diploid oocyte and dispermy.Conclusions:These results indicate a dose-response relationship between the PMSG dose and the incidence of polyploidy in the CD-1 mouse. Both a disturbance at maturation division and an error at fertilization were the cause of polyploidy.

Adrenal and sex steroid hormone production by a virilizing adrenal adenoma and its diagnosis with computerized tomography

The presence of an androgen-secreting tumor in a 29-year-old woman was confirmed and its location was determined by computerized axial tomographic (CAT) scanning. The hormone production from this virilizing adrenal adenoma was studied in vivo and in vitro. The major secretory products of the tumor (as compared to normal adrenal tissue) were testosterone (24-fold) and 17 beta-estradiol (five-fold). Although the adenoma produced lesser amounts of dehydroepiandrosterone sulfate (DHEAS), the demonstration of elevated serum testosterone and DHEAS in serial samples was a better marker for an androgen-secreting adrenal tumor than were the urinary 17-ketosteroids, which remained in the upper limit of normal. The hormone production from the tumor depended neither on adrenocorticotropic hormone nor on human chorionic gonadotropin. The conclusions were that: (1) on the basis of serial measurements of serum testosterone and DHEAS, virilizing adrenal adenomas may be suspected when the concentrations of these hormones reach or exceed 200 ng/dl and 6,600 ng/ml, respectively; (2) the high-resolution CAT scanner can accurately localize these tumors; (3) cosmetic and menstrual dysfunction regressed after resection of the tumor; and (4) virilizing adrenal adenomas may produce both androgens and estrogens.

Direct effects of clomiphene citrate on the steroidogenic capability of human granulosa cells

The effects of clomiphene citrate (CC), 17 beta-estradiol (E2), and human chorionic gonadotropin (hCG) on the accumulation of progesterone (P) and 20 alpha-hydroxy-4-pregnen-3-one (20 alpha-OHP) in cultured human granulosa cells (GC) were examined. In addition, the metabolism of [4-14C]pregnenolone and accumulation of [4-14C]P in response to CC and E2 were determined. The authors conclude the following: (1) the dose-dependent inhibition of P and 20 alpha-OHP production by CC in GC was not reproduced by E2, (2) hCG abolished these effects of CC, (3) these inhibitory actions of CC were not associated with altered 3 beta-hydroxysteroid dehydrogenase activity nor P catabolism indicating that, (4) these actions by CC on the GC occur at some step(s) during steroidogenesis preceding the formation of pregnenolone. These findings may explain, at least in part, the luteal deficiency experienced by women treated with CC, and they also provide a rationale for the use of hCG supplementation during ovulation induction with CC.

Effect of cannabinoids on progesterone production by ovarian granulosa cells of pig and rat

Abstract Various cannabinoids inhibited both basal and FSH-stimulated progesterone synthesis by pig and rat granulosa cells in vitro in a dose- (0.09 – 16 μM) and time- (4 – 24 h) dependent manner. The data present further evidence for a possible direct interference of cannabinoids with ovarian functions.