Precocious development of the testes in chicks following parasagittal knife cuts of the lateral hypothalamic area.

Early development of the testes was effected in chicks following parasagittal knife cuts through the entire lateral hypothalamic area (extending from preoptic to mammillary region). Associated with the accelerated development of the testes was a significantly reduced body weight compared to sham-operated controls (P less than 0.05). Bilateral cuts involving solely the anterior or posterior hypothalamic regions did not cause precocious puberty. At this time the critical fiber tracts which were bilaterally sectioned and their associated neurohumoral mechanism responsible for the initiation of sexual maturation are unknown.