Uptake of tritiated thymidine by primordial germinal cells in the ovaries of the adult slender loris

Abstract

Six adult lorises (Loris tardigradus lydekkerianus) in anoestrus were selected for study. Four of the animals were pretreated with an injection of 0·5 mg oestradiol-17β, two were given FSH (2 × 50 i.u. with a 12-hr interval), while the remaining two were not treated with hormones. All of the animals were subsequently given a subcutaneous injection of 0·5 mCi [³H]thymidine and their ovaries were recovered for autoradiography 24 hr later.It was found that the non-follicular germinal cells within 'nests' in the ovarian cortex actively incorporated the radioisotope. Some of the labelled germinal cells appeared to reach the pachytene-diplotene stages of meiotic prophase, although this would not be expected to occur in such a short time after treatment. None of the labelled germinal cells appeared to enter upon the phase of follicular growth, although a few (especially in ovaries treated with oestrogen and FSH) seemed to be in primordial follicles consisting of an incomplete layer of flattened cells.