Insulin and Amino-acid Regulation of Polysomes in Perfused, Diabetic Rat Liver

Effects of anaerobiosis, glucose, insulin and glucagon on glycogen metabolism in isolated parenchymal rat liver cells

“…The present data show that glucagon in addition to its well-established glycogenolytic effect inhibits glycogen synthesis by a direct action on isolated liver cells, thus proving the functional significance of the reduced glycogen synthetase activity observed in vivo [ 111 and in the perfused liver [ 141. Glycogen and glucose may be regarded as the primary regulators of glycogen metabolism, whereas Insulin, which is known to influence liver protein synthesis [23] and degradation [24] may possibly potentiate the glucose effect by stimulating the formation of the glycogen synthetase phosphatase which is activated by glucose [l] . The rapid turnover of the latter enzyme [25,26] is compatible with the disappearance of glucose stimulation and the appearance of glycogenic insulin sensitivity upon starvation [ 161 , whereas the enzyme activity may be maximal in lightly-fasted rats.…”

Control of Glycogen Metabolism in Isolated Rat Liver Cells by Glucose, Insulin and Glucagon

“…The significances (probability levels) of the cycloheximide and insulin effects are indicated. possible that the hormone promotes this effect by influencing liver protein synthesis and degradation (Ekren et al 1971, Seglen 1971.…”

Effects of amino acids, ammonia and leupeptin on protein synthesis and degradation in isolated rat hepatocytes

“…Amino acids stimulate hepatic protein synthesis in vivo (Munro, 1968;Sidransky etal., 1968;Pronczuk et al, 1970), in the isolated perfused rat liver (Jefferson & Korner, 1969;Ekren et al, 1971;Van Den Borre & Webb, 1972;Fausto, 1972;McGown et al, 1973;Woodside et al, 1974), in isolated rat hepatocytes (Grant & Black, 1974;Seglen, 1976a;Weigand et al, 1977;Seglen & Solheim, 1978a) and in a variety of other experimental systems in vitro (Eliasson et al, 1967;Smulson & Rideau, 1970;van Venrooij et al, 1970van Venrooij et al, , 1972Lee et al, 1971;Christman, 1973). The amino acids may exert their effect by being substrates for protein synthesis, by providing energy, or by unknown regulatory mechanisms (Seglen & Solheim, 1978b).…”