AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 3 543-R551, Copyright © 1986 by American Physiological Society
Effects of atriopeptin and chicken heart extract in Gallus domesticus
C. M. Gregg and R. F. Wideman Jr
Effects of Ser-Leu-Arg-Arg-atriopeptin III (ANP) and chicken heart extract
(CHE) were compared during unilateral renal portal infusion in anesthetized
Single Comb White Leghorn chickens. The purpose was to determine whether
renal effects were glomerular and/or tubular. Both CHE and ANP caused
substantial decreases in mean arterial pressure but had different renal
actions. ANP caused small but significant increases in both absolute and
fractional sodium excretion, but these effects were modest compared with
those reported in mammals. Although there was a tendency for higher
fractional sodium excretion in the portal infused kidney, the difference
was not significant (0.1 less than P greater than 0.05). ANP also increased
glomerular filtration rate (GFR), urine flow rate (UFR), and osmolal
clearance and decreased estimated renal vascular resistance. In contrast,
CHE decreased GFR and increased resistance. In contrast, CHE decreased GFR
and increased fractional potassium excretion in the infused kidney. After
CHE infusion was stopped, GFR and UFR increased, and there was a further
transient kaliuresis. No natriuretic effects were ever seen with CHE.
Chickens apparently lack potent mammalian-type cardiac natriuretic
factor(s) and/or have a limited capacity for natriuresis in response to
mammalian ANP. Because hypotension was the most prominent avian response to
both CHE and ANP, endogenous vasoactive factor(s) in chicken hearts may
function to regulate blood pressure rather than blood volume.
