SIGNIFICANCE OF CHANGES IN RENAL AND HEPATIC L-GLUTAMIC ACID DEHYDROGENASE ACTIVITY IN HYPOPHYSECTOMIZED OR NORMAL RATS TREATED WITH GROWTH HORMONE OR THYROXIN*
LARGELY as a result of studies by Braunstein and co-workers (1939, 1945), attention has been directed to a pathway of amino acid catabolism in which transaminases and L-glutamic acid dehydrogenase are involved. It seemed of obvious interest to determine whether or not the activity of the latter enzyme in tissues is diminished during growth induced with somatotrophin preparations, for it is conceivable that the observed anabolic effects might be due in part to interference with the oxidative deamination of glutamic acid formed from other amino acids by transamination. experimental For our studies of L-glutamic acid dehydrogenase, normal and hypophysectomized Sprague-Dawley rats of the same age were obtained simultaneously from the same source.1 Since these animals were also used for studies on tissue cathepsin, details concerning the design of experiments, growth hormone preparation, diet, handling of tissues, and some of the methods of analysis, have already been given (Mathies, Palm, and Gaebler, 1951).