GROWTH AND OBESITY IN MALE RATS AFTER PLACEMENT OF VENTROMEDIAL HYPOTHALAMIC LESIONS AT FOUR DIFFERENT AGES

Abstract

Ventromedial hypothalamic lesions in weanling female rats have been reported to result in a greater reduction of growth than placement of such lesions in older animals (Bernardis & Skelton, 1966). The present report deals with a parallel study in male rats of corresponding ages. Male Holtzman rats received bilateral electrolytic lesions at the age of 26 days (Group 1), 59 days (Group 3), 75 days (Group 5) and 140 days (Group 7). Nonlesioned rats of the same age served as controls (Groups 2, 4, 6 and 8). The methods used were identical with those in the study on female rats. Table 1 shows that, while the body weight of 26-day-old rats was unaffected when compared with controls of the same age, the rats lesioned at older ages (Groups 3, 5 and 7) weighed significantly more than their controls after 6 weeks. In contrast, linear growth (body length, tail length) was