Abstract
Twenty-day-old male albino rats were subjected to bilateral lesions of the ventromedial nucleus-mammillary body area. The hypothalamic damage resulted in the following modifications: reduction in body, pituitary, and tests weight, disorganization of tubules, absence or reduction of sperm, and partial atrophy of the seminal vesicles and ventral prostate. The results are interpreted as supporting the concept of posterior hypothalamic participation in the regulation of pituitary gonadotropic activity in the immature male rat.