Karyometric changes in the development of the medial and lateral preoptic area of the mouse after gonadectomy

A karyometric study of the medial and the lateral preoptic area of the male albino mouse has been carried out with the aid of a Leitz Image Analysis System (ASM). We have measured nuclear sizes of a control group of sixty mice, aged from the 5th to the 190th day of life. Another group of prepuberally castrated male mice, has been studied at the 25th, 35th, 45th, 55th and 85th postnatal day. The medial and the lateral preoptic area show different development patterns in the control group, and differential effects of castration in these zones were observed. The medial preoptic area, which has frequently been related to changes of sex hormone levels, experiments more important and statistically significant variations than the lateral preoptic area.