Brief cortisol exposure elevates adrenal phenylethanolamine N-methyltransferase after a necessary lag period.
The present study, using bovine adrenal medullary cells, characterized in detail the time course of regulation of phenylethanolamine N-methyltransferase activity following brief glucocorticoid exposure. Cortisol pulses (10(-4) and 10(-5) M), as short as 15 min, increased phenylethanolamine N-methyltransferase activity measured 2 days following cortisol exposure, with a required lag period of 18 h or more. Phenylethanolamine N-methyltransferase activity was increased 2 days following brief (2 h) exposure to cortisol in concentrations that reach the medulla in vivo (10(-6) to 10(-4) M). Phenylethanolamine N-methyltransferase activity following both continuous and 2 h pulses of 10(-5) M cortisol were reduced by the glucocorticoid receptor antagonist, RU 38486. A 2 h pulse of nicotine (10(-5) M) increased phenylethanolamine N-methyltransferase activity with a lag period of at least 18 h, while combination treatment of nicotine and cortisol (10(-4) M) produced significantly higher increases in phenylethanolamine N-methyltransferase compared to either treatment alone. Therefore, this study provides novel in vitro evidence for the regulation of adrenomedullary phenylethanolamine N-methyltransferase activity, following a necessary lag period, by acute changes in both cortisol and nicotine.
Betito
K
K
McGill University, Department of Pharmacology & Therapeutics, Douglas Hospital Research Center, Montreal, Quebec, Canada.
Diorio
J
J
Boksa
P
P
D000313:Adrenal Medulla / Q000166:cytology / Q000201:enzymology*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004357:Drug Synergism; D006854:Hydrocortisone / Q000494:pharmacology*; D015735:Mifepristone / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*
D015735:Mifepristone; D009538:Nicotine; D010625:Phenylethanolamine N-Methyltransferase; D006854:Hydrocortisone