Hypertension, Vol 4, 676-680, Copyright © 1982 by American Heart Association
VS Donoso and MD Bailie
Cytoplasmic microtubules appear to play a role in the secretion of a
variety of protein and protein hormones. Involvement of microtubules in
renin secretion has been hypothesized but not established. The present
studies were designed to determine: 1) if the antimicrotubule drug,
colchicine, would alter plasma renin concentration (PRC); and 2) if changes
in PRC could be related to an effect on cytoplasmic microtubules. Dose
response experiments in Sprague-Dawley rats showed that 0.4 or 0.8
mg/kg/day i.p. of colchicine for 3 days significantly increased PRC while a
dose of 0.2 mg/kg/day was without effect. The increase in PRC at the higher
doses was associated with toxicity of the drug. In other experiments, rats
pretreated with colchicine (0.2 mg/kg/day) or saline received either
furosemide (5 mg/kg) or isoproterenol (25 micrograms/rat) i.p. to stimulate
renin secretion. Colchicine at a dose that did not alter basal PRC
significantly inhibited an increase in PRC after stimulation with either
isoproterenol or furosemide. Lumicolchicine, a structural isomer of
colchicine without antimicrotubule activity, did not alter the response to
isoproterenol stimulation. These data suggest that microtubules play a role
in the increase in renin secretion following stimulation.
ARTICLES
Effect of colchicine on drug-induced changes in plasma renin concentration in rats