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  • Author: P. C. STEPTOE x
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Positive identification of the sperm midpiece and tail in the vitellus establishes beyond reasonable doubt that pronucleate eggs are undergoing fertilization. Previously Edwards, Bavister & Steptoe (1969) tentatively identified sperm midpieces in pronucleate human eggs fertilized in vitro. Unequivocal evidence of midpieces and tails in eggs undergoing fertilization is now presented. Oocytes recovered from two ovaries excised 3 hr previously were cultured in a mixture containing three parts follicular fluid : one part of Bavister's medium (Bavister, 1969). Four samples of follicular fluid were used, three being straw-coloured and a fourth, which was slightly pink, probably came from an atretic follicle. After 36 to 37 hr in culture, the eggs were washed through two or three changes of Bavister's medium, the dilution of the follicular fluid being approximately 1:100. Ejaculated spermatozoa were washed twice in this medium and then added to some of the eggs at a concentration of
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Ruth E. Fowler, N. L. Fox, R. G. Edwards and P. C. Steptoe

Summary. Granulosa cells were aspirated 3–4 h before the expected time of ovulation from 10 follicles of 4 patients treated with gonadotrophins: 4 of the follicles were immediately preovulatory. The granulosa cells were cultured for 10 h with 17α-hydroxypregnenolone or dehydroepiandrosterone and samples of medium removed at 3 and 10 h were assayed for 6 steroids.

Granulosa cells were unable to synthesize androgens from endogenous substrate or undertake conversions via the Δ5 pathway, but cells from all follicles were capable of aromatizing exogenous androgens to oestrogens although this capability was reduced in cells from follicles beginning to luteinize. Granulosa cells from preovulatory follicles synthesized more progesterone from endogenous substrate than cells from follicles which had not begun to luteinize. The results provide further support for the two-cell theory of oestrogen biosynthesis whereby granulosa cells aromatize androgens which are synthesized by the thecal cells in vivo.

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R. G. Edwards, R. E. Fowler, R. E. Gore-Langton, R. G. Gosden, E. C. Jones, C. Readhead and P. C. Steptoe

We wish to present an analysis of the data gained by a group of workers studying various aspects of ovarian activity. Our work has been concerned primarily with two aspects of the development of follicles: the initiation and control of follicular growth, and differentiation and steroidogenesis in follicles approaching ovulation. The scope of our contributions spans the lifetime of the female from the early stages of growth in the fetal ovary to the final stages of follicular development in ageing females and includes both animal and clinical studies. The results are given in two main sections: follicular growth, and normal and abnormal differentiation and steroidogenesis in follicles approaching ovulation. Several aspects of follicular growth are considered in the discussion.