Prolactin Potency of the Cephalic and the Caudal Lobe of the Anterior Pituitary in Relation to Broodiness in the Domestic Fowl

RIDDLE, Bates and Lahr (1935) reported that prolactin induced broodiness in laying fowl. Burrows and Byerly (1936) showed that pituitaries from broody hens contained more prolactin than those from laying hens; and this was confirmed by Saeki and Tanabe (1955). Various attempts have been made to interrupt broodiness, but the results were not always satisfactory. Nakajo (1952 Nakajo (1953) reported that electrical stimulation of the head of broody hen and lighting at night were successful to the interruption. Hormonal changes in the anterior pituitary have not been investigated. Rahn and Painter (1941) divided the anterior pituitary of fowl into two cytologically distinct regions and designated them as “cephalic” and “caudal” lobes. Yasuda (1953) observed that these two lobes of broody hens were different histologically from those of laying hens. In the cephalic lobe basophiles decreased in number together with increase of chromophobes, while in the caudal lobe acidophiles increased in number…