Hepatic and renal protein synthesis in normal, diabetic and ketotic Chinese hamsters.

Two aspects of protein synthesis were studied in vitro in tissue extracts prepared from normal, diabetic and ketotic Chinese hamsters. Firstly, the activity to support polyuridylic acid (poly U)-dependent polyphenylalanine synthesis fromC-phenylalaninet RNA was measured in the liver ribosomes and no significant difference was observed between diabetic hamsters (0.310±0.007 nCi/min/mg ribosomal proteins) and their controls (0.325±0.015), or between ketotic hamsters (0.256±0.013) and their controls (0.274±0.018). Secondly, activity in protein synthesis with endogenous mRNA's was followed in the postmitochondrial supernatant (PMS) fraction after the removal of endogenous amino acid pools by gel filtration. The rate of amino acid incorporation was measured in both liver and kidney extracts withC-leucine, lysine, serine, or glycine as labels. The initial rates of incorporations in the diabetic liver PMS ( Leu = 8.01±1.64 pmole/min/mg protein; Lys = 2.90±0.56; Ser = 3.40±0.60; Gly = 3.34±0.66), and in the ketotic PMS ( Leu = 8.48±2.06; Lys = 3.49±0.82; Ser = 4.11±0.80; Gly = 3.73 ±0.81) were similar to those in the matched controls ( Leu = 8.60±1.06; Lys = 3.14±0.37; Ser = 3.70±0.54; Gly = 3.38 ±0.37). Likewise, the amino acid incorporations in the diabetic kidney PMS ( Leu = 4.38 + 1.09; Lys = 1.26±0.28; Ser = 1.98±0.29; Gly = 1.81±0.32), and in the ketotic kidney PMS ( Leu = 5.39±1.29; Lys = 1.79±0.4; Ser = 1.9±0.18; Gly = 1.97±0.15) were not significantly different from those in the normals ( Leu = 5.32±0.56; Lys = 1.60±0.19; Ser = 2.06±0.22; Gly = 2.02±0.18). It is concluded that the diabetic and ketotic Chinese hamsters retain normal activity in the reported two aspects of protein synthesis. [ABSTRACT FROM AUTHOR]