Organ culture as a model of studying follicular development and function of postnatal mouse ovaries.

Ovarian organ culture was used to study the influence of various gonadotropin hormones (100 ng FSH, 100 ng LH, 100 ng LH added together with 100 ng FSH; 1 i.u. hCG or 10 i.u. PMSG) on growth and development of follicles as well as on steroid secretion by ovaries of postnatal, 15-day-old mice. Ovaries were aseptically removed and single organs were placed on a piece of lens paper which was supported by a stainless steel grid in the small organ culture dish. The cultures were maintained in medium M199 supplemented with 5% of calf serum in a CO2 incubator at 37 degrees C. The morphological changes and steroid secretion measured by appropriate RIAs were studied. The stages of follicular development and the incidence of particular types of follicles were scored. Progesterone and estradiol were detected in the medium by radioimmunoassay. Differences between control and gonadotropin stimulated ovaries were found in the number of the ovarian follicles in more advanced maturation stages. There was increased number of multilaminar and antral follicles in FSH and FSH plus LH treated cells. The adding of gonadotropin hormones to the culture medium stimulated significantly progesterone secretion. The most significant effect was observed in media of cultures treated with LH and hCG. As to estradiol secretion the highest stimulatory effect was seen in cultures supplemented with FSH alone, together with LH and with PMSG. The organ culture technique applied in the current study could be a suitable model of studying the interaction of various factors as well as its effect on ovarian differentiation and on selection of dominant follicles. This system allows maintaining the structural integrity of the whole ovary, thus in the physiological functional status of the organ.