Fluorescence Localization of Luteinizing Hormone/ Human Chorionic Gonadotropin Uptake in the Primate Ovary. II. Changing Distribution during Selection of the Dominant Follicle

Abstract

Gonadotropin receptors have been localized in ovarian compartments primarily by incorporation of radiolabeled hCG. The recent development of a fluorescein-hCG conjugate retaining biological and immunological properties similar to native hCG has facilitated localization of ovarian LH/hCG binding in vivo. During menses in the primate ovarian cycle, no follicle in either ovary demonstrated a strong affinity for the hormonal conjugate. However, areas of fluorescence were associated with the interstitial cell glands of both ovaries from each monkey throughout the ovarian cycle. By the seventh day of the menstrual cycle, a unique pattern of thecal fluorescence circumscribed a single follicle in one ovary from each monkey. By days 9 and 11, the follicle surrounded by the unique thecal fluorescence was clearly the largest follicle in either ovary, such that it was judged to be the dominant follicle. On the basis of unique binding characteristics of the fluorescein-hCG conjugate by the surrounding thecal tissue, the putative dominant follicle was identifiable by day 7 of the menstrual cycle, even though its size was not yet a distinguishing factor. These findings further suggest that thecal tissue associated with the dominant follicle, and perhaps the interstitial component, influences the evolution of the dominant follicle through enhanced LH uptake during the midfollicular phase of the primate ovarian cycle. (J Clin EndocrinolMetab51: 903, 1980)