Cornelia P. Channing

The Role of Nonsteroidal Regulators in Control of Oocyte and Follicular Maturation

Publisher Summary This chapter discusses the role of nonsteroidal regulators in control of oocyte and follicular maturation. The ovarian follicle is bathed in a fluid rich in steroid hormones as well as nonsteroidal regulators which interact to serve to control its maturation, responsiveness to gonadotropins, as well as to lead to control of the maturation of its oocyte. The orderly maturation of an ovarian follicle and its oocyte is controlled by pituitary LH and FSH in concert with local intrafollicular regulators. The principal nonsteroidal follicular regulators are an oocyte maturation inhibitor, a luteinization inhibitor, a luteinization stimulator, FSH receptor binding inhibitor, and inhibin-F. OMI is a polypeptide

Stimulatory effects of prostaglandins upon luteinization of rhesus monkey granulosa cell cultures.

Prostaglandins (Pg) were added at each medium change to cultures of granulosa cells obtained from 1) mid-follicular phase and preovulatory follicles of 4 untreated monkeys, 2) 8 human menopausal gonadotropin (HMG) treated and 3) 8 pregnant mares serum gonadotropin (PMSG) treated rhesus monkeys. Pg E1 or E2 stimulated progestin secretion and morphological luteinization in each group of cultures with a minimal effective dose being about 0.01 μg/ml and a maximal dose being between 10 and 100 μg/ml. The effect of Pg E2 was less than that of human luteinizing hormone (hLH). Pg A1 and PgF2α had less of a stimulatory effect compared to PgE2 or PgE1 with an order of effectiveness being PgE2 or PgE1 >>Pg A1 > PgF2α. Addition of 10 μg of PgF2α or PgE2 with a maximal dose of hLH (0.1 μg/ml) markedly inhibited the effect of the LH. It is concluded that prostaglandins are not luteolytic when added alone to monkey granulose cell cultures but at a dose of 10 μg/ml inhibit the luteinizing action of exogenous LH upon monkey granulosa cell cultures.

SELECTIVE INHIBITORY EFFECT OF PORCINE FOLLICULAR FLUID ON FOLLICLE STIMULATING HORMONE SECRETION IN ANTERIOR PITUITARY CELLS IN CULTURE

Incubation of rat anterior pituitary cells in culture with porcine follicular fluid (treated with charcoal to remove steroids) led to a marked inhibition of spontaneous FSH release while no effect was observed on basal LH secretion. The inhibitory effect of follicular fluid was, however, less specific on LHRH‐induced gonadotropin release. Although more potent on FSH than LH release, a significant inhibition of LH release induced by the neurohormone was also observed. This inhibitory activity is mainly associated with material of MW 10000 daltons.

Effects of prostaglandin inhibitors, 7-oxa-13-prostynoic acid and eicosa-5,8,11,14-tetraynoic acid, upon luteinization of rhesus monkey granulosa cells in culture

Abstract In order to determine whether or not prostaglandins are an intermediate in luteinizing hormone (LH) and human chorionic gonadotropin (hCG) action upon monkey granulosa cell luteinization an inhibitor of prostaglandin action 7-oxa-13-prostynoic acid, and an inhibitor of prostaglandin biosynthesis, eicosa-5,8,11,14-tetrynoic and have been added to cultures of monkey granulosa cells obtained from normal preovulatory monkeys and monkeys treated with pregnant mares serum gonadotropin (PMSG). At a dose of 10 or 50 μ g/ml 7-oxa-13-prostynoic acid had no effect on spontaneous luteinization of cultures of granulosa cells harvested from preovulatory monkeys. If 10 or 50 μ g/ml of the prostynoic acid was mixed with 0.1 μ g/ml hCG or 0.01 μ g/ml LH, it inhibited the stimulatory action of the gonadotropins upon morphological luteinization and progestin secretion in cultures of granulosa cells obtained from PMSG treated monkeys. A dose of 50 μ g/ml of 7-oxa-13-prostynoic acid also inhibited the stimulatory effect of prostaglandin E 2 (Pg E 2 ) upon the cultures. A dose of 5 μ g was without effect on the hCG or Pg E 2 effect. 50 μ g/ml of the prostynoic acid when mixed with either 0.1 μ g/ml hCG or 1 μ g/ml Pg E 2 produced necrotic changes in the cultures detectable after 8–10 days of culture. When added alone the prostynoic acid had no necrotic effects on the cultures. 100 μ g/ml but not 1, or 10 μ g/ml eicosa, 5,8,11,14-tetraynoic acid inhibited the response of cultures of granulosa cells obtained from PMSG treated monkeys to 0.1 μ g/ml hCG. It is concluded that prostaglandins may be an intermediate in the action of LH or hCG upon granulosa cell luteinization. Caution must be used in interpretation of data using prostaglandin inhibitors since they can exert necrotic effects in the presence of prostaglandins or hCG.

Stimulatory effects of gonadotropins on the formation of cyclic adenosine 3′,5′-monophosphate by porcine granulosa cells

Abstract The addition of luteinizing hormone (LH) or follicle stimulating hormone (FSH) to porcine granulosa cells stimulated cyclic adenosine 3′,5′-monophosphate (cyclic AMP) formation from intracellularly labeled ATP. The LH stimulatory effect was larger than that of FSH. The effects of maximal doses of LH and FSH were not additive in the presence or absence of a phosphodiesterase inhibitor, aminophylline. In view of the previous findinf that exogenous cyclic AMP can mimic the effect of gonadotropins upon luteinization of granulosa cells, these results indicate that cyclic AMP is a mediator of this action of gonadotropins.

Stimulatory effects of follicle-stimulating hormone and luteinizing hormone upon secretion of progesterone and inhibin activity by cultured infant human ovarian granulosa cells**Supported in part by grant HD-08834 from the National Institute of Child Health and Human Development.

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.

Effect of follicle-stimulating hormone upon estrogen and progesterone secretion by cultures of monkey granulosa cells recovered during the periovulatory period**Supported by NIH grant HD08834 to C. P. C. and a grant ELIAS GmbH (Bonn) to L. E. R.

For determination of how exposure of the monkey follicle to the preovulatory luteinizing hormone (LH)/follicle-stimulating hormone (FSH) surge alters its responsiveness to FSH in terms of estrogen and progesterone secretory ability, monkey thecal tissue and granulosa cells were harvested prior to and during the midcycle LH/FSH surge and cultured for 8 days with testosterone and with and without 100 ng human FSH. The addition of FSH enhanced estrogen secretion in culture (6.8 and 7 times on the average after 6 and 8 days, respectively; P less than 0.05) by granulosa cells if they were harvested prior to, but not during, the midcycle LH/FSH surge. In contrast, the FSH could stimulate granulosa cell progesterone secretion if the cells were harvested both prior to (60- to 100-fold stimulation) and during the midcycle LH/FSH surge (10- to 60-fold stimulation; P less than 0.05). It can be concluded that exposure of the preovulatory monkey follicle to the midcycle LH/FSH surge alters its responsiveness to FSH in terms of estrogen secretion.