Arginine metabolism and urea synthesis in cultured rat skeletal muscle cells

Abstract

Skeletal muscle is known to contain arginase, but, because this enzyme is also present in erythrocytes, the exact origin of arginine-derived ornithine in peripheral tissues is uncertain. In the present studies, skeletal muscle cells obtained from regenerating hindlimb muscle of adult rats were grown in primary tissue culture for approximately 3 wk and then studied in regard to changes in medium amino acid concentrations over a 48-h period. The consumption of arginine and serine was observed in parallel with the production of ornithine, proline, citrulline, glycine, and urea. Medium threonine and methionine concentrations were relatively constant over 48 h. Incubation of muscle cells with [U-14C]arginine resulted in the formation of [14C]ornithine and [14C]proline at rates at least 10-fold greater than could be accounted for by enzyme constituents of fetal calf serum. In addition, [guanido-14C]arginine was converted to [14C]urea and [U-14C]serine was converted to [14C]glycine. These studies indicate that cultured skeletal muscle cells contain a high arginase capacity and actively synthesize ornithine and urea from arginine.

Involvement of eukaryotic translation initiation factor 5A (eIF5A) in skeletal muscle stem cell differentiation

“…Spermidine can then be used for eIF5A hypusination. Rat skeletal muscle cells in culture possess high arginase activity (Pardridge et al, 1982). So, the treatment of satellite cells with L-arginine could suppress the cell differentiation inhibitory effect of GC7.…”

Horizontal gene transfer provides insights into the deep evolutionary history and biology of Trichinella

“…This makes serum a potential source of cyanate for the encysted worm. However, Pardridge et al (1982) demonstrated in culture, that rat striated muscle cells derived from regenerating hindlimbs were well capable of synthesizing ornithine and urea, and that production was linked to the utilization of serine and arginine in the presence of high levels of cell-derived arginase I which has been linked to a multitude of human diseases ( Caldwell et al, 2018 ). Pandya et al (2019) also reported elevated levels of arginase I in aged muscle cells as did Wu et al (2001) who linked arginase I levels in rat aortic smooth muscle cells to the escalation of cell proliferation.…”

Protective Effects of Ghrelin on Fasting-Induced Muscle Atrophy in Aging Mice

“…Serum arginine levels were significantly reduced in both AG-and UAG-treated mice ( Figure 4E), whereas serum taurine and threonine levels were significantly reduced in AG-treated mice only ( Figures 4F and 4G). Skeletal muscle is known to express arginase (52). Although the major sites of arginine biosynthesis are the small intestines and kidney, the enzyme arginase drives l-arginine catabolism to l-ornithine, in competition with catabolism to nitric oxide (NO) by NO synthase; this competition has been suggested to limit NO production (53).…”