RT Journal Article
SR Electronic
T1 Effect of Hydrocortisone and Insulin on Uptake of α-Aminoisobutyric Acid by Isolated Perfused Rat Liver
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 66
OP 76
VO 1
IS 1
A1 JOHN W. CHAMBERS
A1 RALPH H. GEORG
A1 ALLAN D. BASS
YR 1965
UL http://molpharm.aspetjournals.org/content/1/1/66.abstract
AB In this study both hydrocortisone and insulin were shown to increase the uptake of a nonmetabolizable amino acid, α-aminoisobutyric acid (AIB), by the isolated perfused rat liver. DNA-dependent RNA synthesis was inhibited by actinomycin D to determine whether the effects of these hormones on transport were independent of their actions on the transcription of genetic information. Actinomycin D inhibited enzyme induction by hydrocortisone approximately 90% without affecting the increase in AIB transport. However, approximately half of the insulin effect on AIB transport was blocked by actinomycin D. The effect of hydrocortisone on the uptake of AIB was completely inhibited by phenoxybenzamine (PBZ), an adrenergic blocking agent. The action of insulin on AIB uptake was not affected by PBZ. Hydrocortisone and insulin together exerted an additive effect on the hepatic uptake of AIB. Both hormones act directly (but apparently at different sites) to increase the AIB uptake by the liver. Most of the steroid action and approximately half of the insulin action appears to be independent of any effect these hormones have on DNA-dependent RNA synthesis in the liver. ACKNOWLEDGMENTS This work was supported, in part, by U.S. Public Health Grant CA-02020 and, in part, by U.S. Public Health Grant 2-RO1-AM-05474. J. W. C., while a predoctoral trainee, was supported, in part, by U.S. Public Health Training Grant 2-T1-GM-58 and, in part, by U.S. Public Health Predoctoral Fellowship GFM-16,435.