Recently intraovarian control of steroidogenesis and oocyte maturation has become a subject of interest. Non steroidal sub- stances secreted locally by the ovarian follicle and corpus luteum have been implicated in control of oocyte maturation follicular ma- turation and steroidogenesis as well as luteal function. In addi- tion some ovarian polypeptides such as inhibin F (folliculostatin) leave the ovary and act as modulators of pituitary function which in turn regulates ovarian function by exhibiting changes in follicle stimulating hormone secretion in response to changes in inhibin. It was desired to see how these intraovarian regulators act to control ovarian function. In addition it was of interest to see what the chemical nature of these intraovarian regulators is. To achieve these ends a meeting was held at the Villa Serbelloni in Bellagio situated overlooking Lake Como. Leaders in this field were invited and asked to vigorously discuss the subject of intraovarian control mechanisms. Their manuscripts comprise this volume. C. P. Channing S. J. Segal CONTENTS Maturation, Morphology, and Endocrine Function of the Ovarian Follicle ---------------------------- 1 Lars Bjersing Role of Ovarian Inhibin (Folliculostatin) in Regulating FSH Secretion in the Female Rat ------ 15 Neena B. Schwartz Purification, Characterization, and In Vitro Produc tion of Inhibin ------------------------------ 37 F. H. de Jong, E. H. J. M. Jansen, W. P. Hermans, and H. J. van der Molen Hormonal Control of Inhibin Secretion -. ------------------ 53 Larry D. Anderson and Dennis J.