Year: 2005
Type: article
Abstract: The present study has established that physiological concentrations of estradiol can modulate stress-induced increases in plasma epinephrine (EPI). In anesthetized female rats, insulininduced hypoglycemia (0.25 U/kg) increased plasma EPI concentration to a significantly greater extent in 14-day ovariectomized (OVEX) rats compared to sham-operated controls. In 17βestradiol (E2)-replaced OVEX rats, the hypoglycemia-induced rise in plasma EPI was significantly reduced compared to OVEX rats. This suppression was due to both decreased adrenal medullary output and increased clearance of EPI. Adrenal venous EPI concentration was significantly reduced in OVEX+E2 rats, suggesting that EPI secretion from the adrenal medulla was decreased by E2 replacement. The underlying mechanism(s) of this apparent E2mediated reduction in secretion could not be established since 1) the expression levels of the biosynthetic enzymes tyrosine hydroxylase and phenylethanolamine N-methyltransferase were not affected in OVEX+E2 rats, suggesting that EPI biosynthesis is similar in these and OVEX 2+ rats; and 2) agonist-induced increases in intracellular CaP Pwere identical in isolated adrenal
Author: Julye M Adams
Institution: University of Kentucky
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1490765286