STEROIDS PRESENT IN THE FOLLICULAR FLUID OF THE MARE

Abstract

SUMMARY Using paper chromatographic techniques, it has been possible to identify the following steroids in the follicular fluid of the mare (results expressed as μg/1.): oestradiol-17β, 460 μg; oestrone, 34 μg; cortisol, 12 μg; progesterone, 124 μg; 17α-hydroxyprogesterone, 66 μg; epitestosterone, 24 μg; androstenedione, 136 μg. In addition to these seven compounds, 136 μg of an unidentified oestrogen-like substance and 52 μg of an unidentified 17-ketosteroid were also present. This is the first time that epitestosterone has been identified as a natural product, and the possible significance of this compound is discussed. 19-Hydroxyandrostenedione, the postulated intermediate in the formation of oestrone from androstenedione, was not detected in this study, and some doubt is therefore cast on the theory that it is an essential intermediate in the biosynthesis of the ovarian oestrogens. The presence of relatively large amounts of an unidentified polar oestrogen in follicular fluid suggests that it may be of some physiological significance, although at the present time no information is available on the biological activity of this compound.