Epidermal growth factor as a new regulator of induction of tyrosine aminotransferase and tryptophan oxygenase by glucocorticoids.
Epidermal growth factor (EGF) dose-dependently enhanced the induction of tyrosine aminotransferase and tryptophan oxygenase by glucocorticoids in primary cultures of adult rat hepatocytes without itself having any effect on these enzymes in the absence of glucocorticoids. The amplifications were observed even with dexamethasone at high concentrations (10(-6) M-10(-5) M) that had a maximal effect. EGF had no effect on induction of tyrosine aminotransferase by glucagon or Bt2cAMP. The effect of EGF was also observed in adrenal-ectomized and submaxillary gland-ectomized rats. These results suggest that EGF is an endogenous amplifier of the action of glucocorticoids.
D000315:Adrenalectomy; D000818:Animals; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D006133:Growth Substances / Q000494:pharmacology; D008099:Liver / Q000201:enzymology; D008297:Male; D051381:Rats; D013363:Submandibular Gland / Q000502:physiology; D014366:Tryptophan Oxygenase / Q000378:metabolism*; D014444:Tyrosine Transaminase / Q000378:metabolism*
D005938:Glucocorticoids; D006133:Growth Substances; D004815:Epidermal Growth Factor; D014366:Tryptophan Oxygenase; D014444:Tyrosine Transaminase