Serum Gonadotrophin Concentrations in Infantile Female Mice

Department of Anatomy, Erasmus University, Rotterdam, and Department of Clinical Endocrinology, Birmingham and Midland Hospital for Women, Showell Green Lane, Sparkhill, Birmingham B11 4HL (Received 10th October 1974) High concentrations of FSH occur in the serum of rats aged 10 to 20 days accompanied, around Day 15, by elevated, but variable concentrations of LH (Meijs-Roelofs, Uilenbroek, Osman & Welschen, 1973; Meijs-Roelofs, Uilenbroek, de Jong & Welschen, 1973). Rapid follicular growth occurs in the mouse ovary within the 1st week after birth (Pedersen, 1969), suggesting that serum FSH concentrations may be high during the infantile period in this species also. Changes in the relative abundance of follicles of different sizes between Days 16 and 20 of age suggest that LH is subsequently of increasing importance for follicular growth (Kent, 1972). The present work was undertaken to determine what changes in gonadotrophin levels occur during prepubertal development in the mouse. Mice of