Rat renal epinephrine synthesis.
Rats that underwent adrenal demedullation had a 93% decrease in plasma epinephrine (E) levels, but did not decrease their renal E. Even further treatment with 6-hydroxydopamine and reserpine failed to lower renal E levels. Similarly, urine E levels failed to decrease after adrenal demedullation and renal denervation. There is a renal E-synthesizing enzyme that differs from adrenal phenylethanolamine-N-methyltransferase (PNMT) in that it is only weakly inhibited by SKF 29661 and can synthesize epinine from dopamine, while adrenal PNMT does so poorly. When an adrenalectomized rat received intravenous [3H]methionine, its urine contained radioactivity that appeared to be [3H]E, with small amounts of [3H]epinine. However, after [3H]methionine was infused in the renal artery, the major product in urine appeared to be [3H]epinine, with a small amount of [3H]E. Adrenal demedullation induced renal E synthesis, but denervation returned the rate of renal E synthesis to control values. The combination of adrenal demedullation, 6-hydroxydopamine, and reserpine treatments increased renal E-forming activity to 350% of control. We conclude that appreciable portions of renal and urinary E are synthesized in the kidney by an enzyme distinct from PNMT. The enzyme is induced by some treatments that lower E and NE levels.
Ziegler
M G
MG
Department of Medicine, University of California, San Diego Medical Center 92103.
Kennedy
B
B
Elayan
H
H
D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D002395:Catecholamines / Q000097:blood / Q000652:urine; D003714:Denervation; D004837:Epinephrine / Q000096:biosynthesis* / Q000097:blood / Q000652:urine; D007668:Kidney / Q000294:innervation / Q000378:metabolism*; D008297:Male; D008780:Methyltransferases / Q000378:metabolism; D010625:Phenylethanolamine N-Methyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D002395:Catecholamines; D008780:Methyltransferases; D010625:Phenylethanolamine N-Methyltransferase; D004837:Epinephrine