The action of the Walker 256 carcinoma and toxohormone on amino acid incorporation into diaphragm protein

Abstract

In rats bearing the Walker 256 carcinoma, the diaphragm was markedly depleted of protein, the proteins of the contractile elements being depleted to a greater extent than sarcoplasmic or extracellular proteins. Under in vitro conditions the incorporation of 3H-4, 5-lysine into the myofibrillar but not the sarcoplasmic proteins of diaphragm was significantly reduced. Toxohormone, prepared from the Walker 256 carcinoma, caused a marked inhibition of the in vitro incorporation of 3H-lysine into diaphragm proteins both when the preparation was injected into the animal and also when it was added to the incubation medium. The inhibitory effect of toxohormone was directed at incorporation into myofibrillar proteins. © 1973.