MYOINOSITOL (INO) EXCESS INDUCES FETAL GROWTH IN HYPOGLYCEMIC RABBITS:

The macrosomia of infants of diabetic mothers (IDM) is believed due to fetal hyperglycemia & hyperinsulinemia. Serum INO, a possible growth factor, is elevated among IDM. Therefore, we studied whether elevated INO is associated with IDM growth stigmata. Pregnant (27-day) rabbits were infused with insulin IV for 48 hrs to maintain blood glucose between 45-90 mg/dl. Group 1 (4 does): continuous INO infusion, 2 gm/kg/day; Group 2 (3 does): no INO. All had free access to water & lab chow. The groups had similar IV total fluid intake/kg maternal serum glucose & insulin/kg/hr. The does were sacrificed on pregnant day 29 and the fetuses studied for growth. Serum INO was significantly higher in Group 1 fetuses than in Group 2 (<.001), with no significant fetal serum C-peptide differences between groups. Group 1 (INO) fetuses had significantly higher body, liver & brain wt., but lung weights were not different (Table). We have demonstrated that excess INO, found also in IDM, increases body, liver & brain wt. despite low maternal & fetal glucose. This suggests possible importance of hypermyoinositolemia in the pathogenesis of macrosomia in the IDM.