Effects of cortisol on tRNA methylase activities in rat mammary carcinoma.
Mammary carcinomas induced in rats by DMBA were divided into three types: I, hard proliferating tumors; II, tumors presenting from an early stage the first signs of cystic degeneration; III, lactating tumors. In all three types, cortisol reduced the protein content by 26%-30%. The already high tRNA methyltransferase activity in type I increased by 200% after cortisol treatment. Hormonal treatment of type II increased the previously reduced control methyltransferases by 37%. In the type III lactating tumors, the total tRNA methyltransferases were inhibited by 35% after cortisol treatment. The methyltransferases of types I and II were separated chromatographically into seven analogous peaks, while the enzymes from type III presented a modified pattern. In each case, cortisol treatment affected the activities of several methyltransferases simultaneously without obvious specificity.
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D005260:Female; D006854:Hydrocortisone / Q000494:pharmacology*; D007700:Kinetics; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D012359:tRNA Methyltransferases / Q000302:isolation & purification / Q000378:metabolism*
D015127:9,10-Dimethyl-1,2-benzanthracene; D012359:tRNA Methyltransferases; D006854:Hydrocortisone