BIOLOGY OF REPRODUCTION 29, 953-962 (1983) 953 Steroid Metabolism by Avian Ovarian Cells During Follicular Maturation BABETTA L. MARRONE’ and FRANK HERTELENDY Departments of Obstetrics and Gynecology and Physiology St. Louis University School of Medicine St. Louis, Missouri 63104 ABSTRACT The profiles of steroid hormones produced by ovarian cells from the domestic hen were exam- ined. Theca cells from the immature, small white follicles (SWFT), the third largest (T3), and largest (Ti) preovulatory follicles, and the ruptured, postovulatory follicle (POFT) were incubated for 3 h at 370 with l HI progesterone (Prog) or 3 HI pregnenolone (Preg). Granulosa cells from the largest preovulatory follicle were incubated with l HI Preg or were coincubated with theca cells and [3 HI Preg. The production of specific steroid metabolites was determined on the basis of coelution of radioactivity with known standard compounds, using an isocratic high-pressure liquid chromatography (HPLC) technique. Granulosa cells converted 93% of l H! Preg substrate to Prog. More Prog was utilized by T3 cells than by Ti and SWFT cells, either when l HI Prog was the substrate or when coincubated with granulosa cells and [3 HI Preg. The major metabolites of Prog were androstenedione, 17-hydroxyprogesterone, and an unidentified compound with an elution time of 53 mm. The POFT cells metabolized l HI Prog to the same extent as T3 cells did, but their profile of steroidogenesis favored production of the unidentified 53 mm metabolite. SWFT cells utilized the least amount of j3 HI Preg substrate. The results point to marked changes in enzyme activities in theca cells during maturation and following ovulation. INTRODUCTION The ovary of the chicken differs from mammalian ovaries in a number of ways. In the chicken, only the left ovary and oviduct are functional; the right ovary and oviduct regress during the early posthatching period under the influence of a factor(s) secreted by the left ovary. The modern domestic hen, selectively bred for egg production, ovulates daily for sev- eral days. The immature, small whitish follicles that survive early atresia become filled with yolk as they mature and increase in size from 5 to about 40 mm in diameter within days. The yolk-filled follicles are attached to the ovary by follicular stalks and are arranged in a size hierarchy, whereby only the largest follicle is ovulated during each ovulatory cycle (Gilbert, 1971; Bahr and Nalbandov, 1977; Burke, 1977). No corpus luteum is formed following ovulation, but the “postovulatory follicle” retains its steroidogenic capabilities, though the precise function of this structure is not known Accepted June 27, 1983. Received February 28, 1983. Reprint Requests: Babetta L. Marrone, PhD, Dept. of Obstetrics and Gynecology, St. Louis University Medical Center, 1325 South Grand Blvd.. St. MO 63104. (Shahabi et al., 1975; Armstrong et al., 1977; Dick et al., 1978; Huang and Nalbandov, 1979; Huang et al., 1979; Hammond et al., 1980; Tojo et a!., 1982). The follicular arrangements and the accurate timing of ovulation in the domestic hen, coupled with anatomic features of the follicles that allow for isolation of pure granulosa and theca cells in abundance, offer unique ad- vantages for studying the influence of follicular maturation on ovarian steroidogenesis. Previous studies have shown that in the hen, as in mammals (Channing et al., 1980), the granulosa and theca cells interact in the produc- tion of steroids (Huang et a!., 1979; Marrone and Hertelendy, 1983). In a previous publica- tion, production of progesterone (Prog) and estrogen by coincubations of granulosa and theca cells were examined (Marrone and Hertelendy, 1983). When incubated with pregnenolone (Preg) substrate, granulosa cells from the largest and third largest preovula- tory follicles converted nearly all the Preg to Prog. When theca cells from the largest and third largest follicles were coincubated with granulosa cells from either follicle, the amount of Prog measured at the end of the incubation period was reduced considerably as compared to incubations of Preg with granulosa cells alone. In addition, when theca cells alone were Downloaded from https://academic.oup.com/biolreprod/article-abstract/29/4/953/2766411 by guest on 21 May 2020