Bo L. Dennefors

Aspects concerning the role of prostaglandins for ovarian function.

The present review briefly summarizes the current view of the mechanisms whereby prostaglandins (PGs) may act to modulate ovarian function. Particular concern is devoted to the aspects of ovarian function which are under current investigation by the authors, namely follicular maturation and rupture, granulosa cell and oocyte maturation, and the formation and maintenance as well as the regression of the corpus luteum (CL). PGs are formed in the granulosa cells of the preovulatory follicle in response to gonadotropin action and are at their highest levels around the time of ovulation. PGs are believed to be obligatory for follicular rupture, but their mechanism of action is still unknown. In the process of oocyte maturation PGs can mimic the stimulatory effects induced by LH or hCG, but are probably not obligate mediators of these effects. The importance of PGs for CL formation and maintenance is so far unsettled, and PGs may be regarded more as modulators than as inducers for these processes. The most well-documented effect of PGs is the induction of CL regression. Evidence is presented that PGs may have this effect also in the human.

Hilus cells from human postmenopausal ovaries: gonadotrophin sensitivity, steroid and cyclic AMP production.

Abstract. Strips of ovarian hilar tissue taken from 11 post‐menopausal women were examined histologically and found to contain clusters of hilus cells in contiguity with non‐mye‐linated nerve fibers. No other steroidogenically active structures were found. Specimens from these strips were incubated for 30 and 240 minutes in Krebs bicarbonate buffer containing 5.5 mM glucose and 1% bovine serum albumin. The specimens produced measureable amounts of androstene‐dione, estradiol‐17β and progesterone in vitro. The major steroid formed was androstenedione, and this pattern of steroidogenesis appeared similar to that of postmenopausal ovarian stroma. However, the amounts of steroids formed were considerably higher than in stromal tissue. This implies that the hilus cells possibly may be of greater importance, qualitatively, than the stroma cells for steroidogenesis in the postmenopausal ovary.

In vitro effect of danazol on steroidogenesis in developing human follicles: An interim report

Abstract. In order to show whether or not danazol exerts direct effects on the cells Of the human ovarian follicle, fOI% cular granulosa and thecal cells of follicles in different stages of development are currently being investigated in short‐term incubation experiments and during more prolonged cell culture.

The Ageing Ovary

Abstract. Studies on the endocrine function of the ageing ovary are briefly reviewed. In the perimenopausal years, follicular function can become defective, leading to variable and often shortened cycle length and frequent anovulation. In the postmenopausal period the ovarian stromal cells continue to secrete variable amounts of steroid, mainly androgens. The endocrine activity of the postmenopausal ovary is generally too low to cause clinical symptoms. Occasional cases of hirsutism and even virilization have been reported in postmenopausal women with non‐neoplastic lesions of the ovary.

OVARIAN STEROID PRODUCTION IN A WOMAN WITH POLYCYSTIC OVARY SYNDROME ASSOCIATED WITH ENDOMETRIAL CANCER

Abstract. A young woman with typical polycystic ovary syndrome (PCO) underwent laparotomy for moderately differentiated endometrial cancer. Specimens from the hyper‐plastic thecal and stromal tissue of the ovaries were incubated for 2 hours in the presence or absence of hCG, 100 IU/ml. Following incubation the tissue content of cyclic AMP and the amounts of progesterone (P), androstene‐dione (A), testosterone (T) and estradiol‐17β (E2) in the incubation medium were analysed. For comparison, thecal cells from normal ovaries of regularly menstruating women were incubated under identical conditions. In vivo, the PCO ovaries secreted several‐fold greater amounts of T than normal ovaries. In vitro, the thecal cells were much more active, steroidogenically, than the stromal cells of the PCO ovary. Furthermore, the hyperplastic thecal cells of the PCO ovary produced several‐fold greater amounts of an‐drogens, and appeared more sensitive to stimulation with hCG, as compared with thecal cells from normal ovaries. The results indicate that in women with PCO associated with endometrial cancer the hyperplastic thecal cells are a significant site of abnormal androgen production and abnormal sensitivity to gonadotropin.

Influence of Clomiphene Citrate in Vivo On Subsequent Steroid Formation and Gonadotropic Responsiveness in Vitro of Isolated Human Follicular Cells

Granulosa and thecal cells from human preovula‐tory follicles, extirpated from the ovaries of women undergoing sterilization by minilaparotomy, were incubated for 2 hours in the presence or in the absence of human gonadotropin (hCG). the follicles were obtained from 16 women, 8 of whom had previously been treated with clomi‐phene citrate (CC) to induce follicular maturation. the tissue contents of cyclic AMP (cAMP) and the content of progesterone (P), testosterone (T) and estradiol‐17β (E2) in the incubation medium were measured. Granulosa and thecal cells from control and CC‐induced follicles all responded to hCG in vitro with increased formation of cAMP. Both granulosa and thecal cells from CC‐induced follicles produced larger amounts of P in vitro than cells from spontaneously matured follicles. There were no other differences in the patterns of steroid formation or reactivity to hCG between the cells from the two types of follicle. It is concluded that CC treatment in vivo induces the growth and maturation of preovulatory follicles with apparently normal biochemical characteristics, as far as the content of and capacity to form cyclic AMP, progesterone, testosterone and estradiol‐17β are concerned.

Steroid Production and Responsiveness to Gonadotropin and Prostaglandins of Human-Ovarian Follicles at Term Pregnancy *

This article was undertaken to correlate the steroidogenic capacity of human follicles in later pregnancy to their histological appearance. Specimens for the study were obtained from the ovaries of 26 women undergoing elective cesarean section. Human chorionic gonadotropin did not influence follicular production of cyclic AMP (adenosine monophosophate) and steroids in vitro. However, prostaglandin E2 and F2 alpha did elicit a stimulating effect on the follicular cyclic AMP system, thus indicating a well-preserved adenylate cyclase system in spite of morphologic signs of early atresia.