Isolation and properties of the FSH and LH-releasing hormone.

Abstract LH-releasing hormone (LH-RH) was obtained in apparently a homogeneous state from extracts of pig hypothalami. The LH-RH preparation isolated has FSH-releasing hormone (FSH-RH) activity, which appears to be intrinsic to LH-RH. The amino acid composition of LH-RH/FSH-RH as determined on acid hydrolysates is: His 1, Arg 1, Ser 1, Glu 1, Pro 1, Gly 2, Leu 1 and Tyr 1. The hormone isolated stimulates the release of FSH and LH in vivo and in vitro in doses of a few nanograms. This polypeptide appears to represent the hypothalamic hormone which controls the secretion of both LH and FSH from the pituitary.