INVIVO GLUCOSE-UTILIZATION BY INDIVIDUAL TISSUES IN VIRGIN AND PREGNANT OFFSPRING OF SEVERELY DIABETIC RATS

Adult off spring of diabetic rats or SDF rats are characterized by insulin resistance in the liver and extrahepatic tissues; this insulin resistance does not worsen during pregnancy (1,2). In this study, we determined the glucose metabolic index in tissues of anesthetized virgin and pregnant control and SDF rats in basal conditions and during a euglycemic hyperinsulinemic clamp. Tissues comprised insulin-sensitive tissues (five skeletal muscles, diaphragm, and periovarian white adipose tissue) and control tissues (duodenum and cerebrum). In addition, this study measured the GMI of placenta and fetuses. In basal conditions, SDF rats showed a slight decrease (9-29%) in the GMI of skeletal muscles compared with control rats; it was not altered by pregnancy in any of the tissues. During physiological hyperinsulinemia, virgin SDF rats exhibited a 25-70% decrease in the GMI of skeletal muscles compared with control rats; this decrease was not observed in diaphragm, or in adipose tissue in which the GMI was found to be increased. During pregnancy, SDF rats did not show an additional drop in the GMI of skeletal muscles, whereas the GMI of both skeletal muscles and adipose tissue was clearly diminished (25-60%) in control rats. The GMI of skeletal muscles was therefore comparable in pregnant control rats and SDF rats. The placental, but not fetal, GMI was increased by 24% during hyperinsulinemia in control rats; the placental and fetal GMIs, in basal and hyperinsulinemic conditions, were similar in control rats and SDF rats. In conclusion, skeletal muscles, but not white adipose tissue, are involved in the peripheral insulin resistance of the SDF rats. However, pregnancy does not induce a further decrease in glucose utilization by skeletal muscles in SDF rats.