Effects of glucagon and an analogue of cAMP on tyrosine aminotransferase in isolated chick embryo hepatocytes.
Hepatocytes were isolated from 17-day-old chick embryos by the use of collagenase. Glucagon and dibutyryl cAMP (bt2cAMP), individually or in combination, stimulated tyrosine aminotransferase (TAT) activity and synthesis in the isolated hepatocytes; maximal stimulation occurred 4 h after exposure of hepatocytes to the inducers. The stimulatory effects produced by glucagon and bt2cAMP were abolished by treatment of hepatocytes with cordycepin or cycloheximide. The effects of the hormone and the cyclic nucleotide were not additive. The induction of the enzyme by glucagon suggests a physiological role for the hormone in the expression of TAT activity during chick embryonic development.
Onoagbe
I O
IO
Department of Biochemistry, University of Manchester, United Kingdom.
Dickson
A J
AJ
D000818:Animals; D003994:Bucladesine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002478:Cells, Cultured; D002642:Chick Embryo; D003513:Cycloheximide / Q000494:pharmacology; D003839:Deoxyadenosines / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005934:Glucagon / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects; D014444:Tyrosine Transaminase / Q000096:biosynthesis*
D003839:Deoxyadenosines; D003994:Bucladesine; D005934:Glucagon; D003513:Cycloheximide; D014444:Tyrosine Transaminase; C058120:cordycepin