Reversion of insulin resistance in the rat during late pregnancy by
infusion with glucose for 72 h.
Ramos, Pilar, and Emilio Herrera.
Centro de Ciencias Experimentales y T[acute]ecnicas, Universidad
San Pablo-CEU, Madrid, Spain
APStracts 2:0139E, 1995.
To determine whether sustained exaggerated hyperinsulinemia in
normoglycemic rats modifies insulin responsiveness during pregnancy,
17-day pregnant and virgin rats were studied after receiving a
continuous intravenous infusion with either 50% glucose or
bidistilled water (controls) (35 ml/day) for 72 h. Plasma glucose was
unchanged while insulin was highly increased, and effect was more
marked in pregnant than in virgin rats. Insulin responsiveness
estimated under the hyperinsulinemic euglycemic clamp with 0.8 IU
insulin/h/kg was lower in control pregnant than in virgin rats, but
higher in pregnant rats than in virgins in the rats that had received
the glucose infusion. The tissue glucose utilization metabolic index
(GUI) was estimated with 2-[3H]-deoxyglucose in the clamped rats. The
GUI was lower in heart, white- and red-fiber skeletal muscle and
adipose tissue in control pregnant rats than in control virgins, and,
although the glucose infusion decreased that index in both red-fiber
muscle and adipose tissue in virgin rats, it increased it in red
-fiber muscle in pregnant rats to the level found in virgin controls.
Results therefore show that when unaccompanied by hypoglycemia,
sustained exaggerated hyperinsulinemia decreases insulin
responsiveness in virgin rats but reverts insulin resistance in late
pregnant rats.
Received 12 January 1995; accepted in final form 19 June 1995.
APS Manuscript Number E8-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.