The control of protein degradation in monolayer cultures of cat hepatocytes.
1. Isolated cat hepatocytes were established in monolayer culture, cell proteins labelled with tritiated leucine and the effects of amino acids and hormones on the regulation of intracellular protein breakdown were studied. 2. Mixtures of essential and non-essential amino acids inhibited the breakdown of long-lived protein, but when tested individually, amino acids except for tryptophan were ineffective. 3. The rate of breakdown of short-lived protein was not regulated by amino acids or hormones, a finding which was similar to that in rat liver cells. 4. The known stimulatory hormones of proteolysis in rat liver such as glucagon, dexamethasone and corticosteroids failed to enhance protein degradation in cat liver cells. 5. These results support the contention that the control of protein degradation in the cat is different to that in the rat and these differences may reflect the unusual protein metabolism of the cat.
Silva
S V
SV
Department of Animal Husbandry, University of Sydney, NSW, Australia.
Mercer
J R
JR
D000305:Adrenal Cortex Hormones / Q000502:physiology; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002415:Cats; D002478:Cells, Cultured; D003907:Dexamethasone / Q000378:metabolism; D005934:Glucagon / Q000502:physiology; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D000596:Amino Acids; D011506:Proteins; D003907:Dexamethasone; D005934:Glucagon