Insulin sensitivity and hemodynamic responses to insulin in wistar
-kyoto and spontaneously hypertensive rats.
Pitre, Maryse, Andre Nadeau, and Helene Bachelard.
Hypertension Research Unit and Diabetes Research Unit, CHUL
Research Center, Laval University, Ste-Foy, Quebec, Canada, G1V
4G2
APStracts 3:0116E, 1996.
The insulin-mediated vasodilator effect has been proposed as an
important physiological determinant of insulin action on glucose
disposal in normotensive human. The present study was designed to
further examined the acute regional hemodynamic effects of insulin in
different vascular beds and explore the relationships between insulin
vascular effects and insulin sensitivity during euglycemic
hyperinsulinemic clamps in conscious, normotensive Wistar Kyoto (WKY)
and spontaneously hypertensive rats (SHR). The rats were instrumented
with intravascular catheters and pulsed Doppler flow probes to
measure blood pressure, heart rate and regional blood flows. In WKY
rats, the euglycemic infusion of insulin (4 and 16 mU kg -1 min -1 )
causes vasodilations in renal and hindquarter vascular beds, but no
changes in mean blood pressure, heart rate, or superior mesenteric
vascular conductance. In contrast, in SHR the same doses of insulin
produces vasoconstrictions in superior mesenteric and hindquarter
vascular beds and, at high doses, increases blood pressure. Moreover,
at the lower dose of insulin tested, we found a reduction in the
insulin sensitivity index in the SHR as compared to the WKY rats. The
present findings provide further evidence for an association between
insulin sensitivity and insulin-mediated hemodynamic responses.
Received 29 January 1996; accepted in final form 4 June 1996.
APS Manuscript Number E48-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96