[Immunochemical identification of the growth hormone and prolactin in the hypophyseal polypeptide spectrum of chickens].

Forty-eight fractions of polypeptides including 39 fractions with a molecular weight of 14-95 kD were identified in chick adenohypophysis by sodium dodecyl sulphate electrophoresis in 10-20% gradient polyacrylamide gel slabs. The immunochemical identification of the polypeptides was performed with the aid of the electroblotting of proteins and antisera to human STH, to bovine prolactin, and to the tissue-specific antigen A-1 of chick adenohypophysis. Antisera to human STH and to antigen A-1 reacted with the same major polypeptide fraction, m.w. 26 kD, characteristic of the caudal lobe of the adenohypophysis. Immunoreactive prolactin was present in chick adenohypophysis in the form of a polypeptide fraction with a molecular weight of 25 kD and in the form of two minor fractions of polypeptides with molecular weights of 27 and 28 kD. The data obtained indicate the identity of the adenohypophyseal tissue-specific antigen A-1 to chick STH.