Endocrine effects of diencephalic lesions in the White Leghorn hen

Electrolytic coagulation of areas on the diencephalon of the adult White Leghorn hen has been made with the assistance of a Stellar stereotaxic instrument and an X-ray machine. Comb and wattle factors, egg-laying cycles, acidophil counts, adrenal corticoid concentration, and histological studies of the oviducts, adrenals, and thyroid glands have been recorded. Cessation of egg-laying was brought about by lesions in the nucleus paraventricularis, median eminence, and pars tuberalis. These lesions also reduced the size of the comb and wattles. Some of the lesioned birds exhibited an increase in acidophils, possibly due to the destruction of an area controlling “normal acidophil levels”. There did not appear to be any correlation between lesioned areas and corticoid titer of any of the birds 2 weeks following the operations. Hens with lesions in the nucleus supraopticus, preoptic division, showed a thyroid histological picture that indicated a reduction in activity of the gland.