Stimulation of Amino Acid Transport in Isolated Diaphragm by Growth Hormone Added in vitro

Abstract
The influence of the pituitary on the transport of α-aminoisobutyric acid-1-C14 into the cells of isolated rat diaphragm was investigated. Hypophysectomy results in a lower-than-normal rate of α-aminoisobutyric acid-1-C14 penetration into muscle. Adding either simian or bovine growth hormone preparations to the incubation medium in concentrations of 2.5 to 25 µg/ml of medium resulted in a doubling of the α-aminoisobutyric acid-l-C14 penetration rate. The stimulatory effect was minimized when the hormone concentration was reduced to 0.25 µg/ml of medium.