AJP - Renal Physiology, Vol 232, Issue 2 84-F91, Copyright © 1977 by American Physiological Society
A smooth muscle active factor isolated from renal cortex of the rabbit
C. B. Brown, D. E. Drum and N. K. Hollenberg
Homogenates of rabbit renal cortex contained a water-soluble material with
striking activity on smooth muscle derived from the rabbit aorta, rat
stomach, and guinea pig ileum--but not rat colon or chick rectum. Evidence
derived from the spectrum of its pharmacologic activity, the influence of
specific competitive antagonists on the smooth muscle responses to the
factor, the influence of proteolytic enzymes and its elution position
during molecular sieve filtration on Sephadex G-10 made it unlikely that
the factor was a prostaglandin, renin, angiotensin, a catecholamine,
serotonin, bradykinin, a nucleotide, a small organic product of local
metabolism, or a small ion. The agent was not found in extracts of renal
medulla, spleen, myocardium, or lung. The smooth muscle response to the
factor was blocked by phenoxybenzamine. The renal cortical factor in
subthreshold concentration also potentiated responses of the rabbit aorta
to angiotensin and norepinephrine. The factor's intrinsic activity and
ability to potentiate the smooth muscle actions of endogenous
vasoconstrictors make it a candidate as a mediator of smooth muscle
responses in a number of states.
