Control of the increased protein synthesis in kidney of nephrotic rats by supernatant factors

Studies of a factor from dystrophic mouse muscle inhibitory towards protein synthesis

“…The increase in each instance depended upon an increased binding of aminoacyl-tRNA to ribosomes. This was due to an increase in the activity of purified EF 1 (Girgis & Nicholls, 1971;Nicholls et al, 1974;Young & Nicholls, 1978) in the soluble cytosol fraction rather than to the presence or absence of stimulatory or inhibitory factors affecting EF 1.…”

“…Previous studies in this laboratory have shown that the pH5-supernatant fraction, which contains most of the EF 1 activity of the cell, together with a relative excess of EF 2 activity, exhibits an increased capacity for peptide synthesis during hypertrophy and hyperplasia of rat kidney and liver (Girgis & Nicholls, 1971;Nicholls et al, 1975Nicholls et al, , 1977Cappon & Nicholls, 1974a,b;Chan et al, 1977). In mice during cardiac hypertrophy resulting from genetic muscular dystrophy a similar situation was observed in the heart muscle (Petryshyn et al, 1977).…”

“…radioactivity 385Ci/mol, 0.56,Ci/mg of tRNA), containing 19 other unlabelled aminoacyl-tRNA species from Escherichia coli strain B, and other chemicals were obtained as described previously (Girgis & Nicholls, 1971Bishay & Nicholls, 1973;Innanen & Nicholls, 1973;Nicholls et al, 1974;Young & Nicholls, 1978). Myosin, actin and tropomyosin were gifts from Dr. A. Forer of York University.…”

“…The pH5-supernatant fraction was obtained from the postmicrosomal supernatant fraction as described by Petryshyn & Nicholls (1976). Rat liver was used to prepare a microsomal fraction that was treated with sodium deoxycholate and salt-washed by the method of Girgis & Nicholls (1971) for the preparation of ribosomes.…”

Regeneration of renal proximal tubules after mercuric chloride injury is accompanied by increased binding of aminoacyl-transfer ribonucleic acid

“…Similar changes were found in kidney responding to growth-hormone administration (Girgis & Nicholls, 1973) or undergoing hypertrophy in response to folic acid (Nicholls et al, 1975). An increase in aminoacyl-tRNA binding also was observed during the increased synthesis of specific kidney proteins, such as the soluble ribonuclease inhibitor during aminonucleoside nephrosis and the microsomal proteins during the induction of kidney enzymes by DDT [1,1,1-trichloro-2,2-bis-(pchlorophenyl)ethane] and polycblorinated biphenyls (Girgis & Nicholls, 1971;Bishay & Nicholls, 1973;Nicholls & Markle, 1974;Cappon & Nicholls, 1974b;Cappon et al, 1976).…”