Renal RNA and DNA contents, as well as estimates of renal plasma flow and glomerular filtration rate, were studied in albino Sprague-Dawley rats subjected to either unilateral nephrectomy and/or unilateral ureteral ligation. RNA and DNA contents of ligated kidneys were markedly higher than those of the contralateral, unligated kidney 24 and 48 h post ligation. These increases in RNA and DNA content of the ligated kidney occurred in the presence of relative decreases inreal plasma flow and glomerular filtration rate in the ligated kidney. Renal RNA and DNA contents were also increased in the remaining kidney following unilateral nephrectomy. The effect of ureteral ligation and unilateral nephrectomy on renal RNA content was found to be additive. These results are inconsistent with theories stating that changes in renal RNA and DNA content are the result of increased renal plasma flow and glomerular filtration rate. The data support a role for a circulating factor which either stimulates renal RNA and DNA accumulation from the lumental aspect of tubular cells or inhibits renal RNA and DNA accumulation from the peritubular aspect of these cells.

Ribosomes were isolated from normal and growing kidney and the protein complement was examined by a two-dimensional gel electrophoretic procedure. Proteins were resolved in the first dimension on the basis of charge and, in the second dimension, on the basis of molecular weight. 60S and 40S ribosomal subunits from normal kidney contained respectively 42 and 31 proteins. 80S ribosomes contained 23 proteins not found with either sub-unit. Nineteen of these proteins were removed from the ribosomes when isolated ribosomes were washed in a high salt buffer. Six proteins of the 80S ribosome corresponded to proteins associated with both sub-units. 80S ribosomal proteins were also studied during compensatory renal hypertrophy after 4-96 h of induced growth. The protein complement displayed by electrophoresis was identical to the pattern seen from normal renal cells.