Further Evidence for Amino Acid Transport as a Site of Action of Growth Hormone.

Abstract

Addition of growth hormone to intact, isolated diaphragms of hypophysectomized rats accelerates the transport of AIB-1-C14 ([alpha]-aminoisobutyric acid) into the intracellular compartment of muscle cells. This is competitively inhibited by leucine and glycine but not by phenylalanine or glutamic acid. These findings suggest that growth hormone stimulates the transport of some, but not all, naturally occurring amino acids as well as that of the nonmetabolizable amino acid AIB. These findings further support the hypothesis that amino acid transport may be a site of action of growth hormone in the regulation of protein metabolism.