[Subcellular aspects of interstitial cell innervation in chick embryo ovary cultured with LH or hCG].

UNLABELLED

Several authors have shown the effect of LH or hCG gonadotrophins on steroid secretion in the chick embryo ovary. However, the effects of luteinising hormone or human chorionic gonadotropin on chick embryo ovary innervation have not been studied. The purpose of the present work was to study the subcellular aspects of interstitial cells innervation in chick embryo ovaries cultured with LH or hCG. Coob's White Rock female chick embryos at 7, 11, 15 and 19 days of incubation (in ovo) were employed. Explants of the left and right ovaries were cultured separately for 4 days in: 1--Basic medium (control): minimum essential medium (MEM-GIBCO) with 10% bovine fetal serum, 2--Basic medium with added LH or hCG (problems). The cultures were processed to be studied ultrastructurally (TEM). Left and right ovary explants were fixed two hours at room temperature in Karnovsky's fixative. The tissues were then post-fixed in osmium tetroxide in 0.1 M cacodylate buffer for one hour and after a rinse in buffer were dehydrated in acetone: afterwards they were embedded in Araldite resin. Thick sections stained with 1% Toluidine blue were examined and photographed using a Zeiss Photo II microscope. Thin sections were stained with uranyl acetate and lead citrate and examined in a Siemens ElmisKop 101 electron microscope.

CONTROLS

In both ovaries the isolated interstitial cells and the appearance of nerve fibers and nerve endings were observed in the explants of 11 day cultured during four days and in a similar way at the age of 15 days of in ovo development.

PROBLEMS

With LH or hCG nerve fibers and nerve endings were observed both in the right gonad and in the medulla of the left ovary in close contact with the steroid-producing interstitial cells. Ultrastructurally, the interstitial cells are recognized by their typical organoids: SER, Golgi apparatus, mitochondria with tubular crests and abundant lipidic droplets. The innervation of these cells were seen in ovaries at 7 days development, cultured during 4 days. The present state corresponds to that of 11 days development in ovo. The nerve endings had mitochondria, microtubules and small and medium-sized vesicles, some with an electrodense content. These results in vitro suggest that innervation of the ovaries is controlled by an indirect mechanism via the hypothalamic-pituitary system and another local with production neurotrophic factors modulated by LH.