UNDERFEEDING OF RAT MOTHERS DURING THE FIRST 2 TRIMESTERS OF GESTATION DOES NOT ALTER INSULIN ACTION AND INSULIN-SECRETION IN THE PROGENY

It has been suggested that impaired insulin action and/or insulin secr etion in adult mammals could be a consequence of severe food restricti on during fetal life. We have determined to what extent glucose homeos tasis and insulin action are modified in male offspring of rats undern ourished only during the first two trimesters of pregnancy. Pregnant f emales then were assigned to one of the following three experimental c onditions. Rats in the first group had their food restricted to 50% of their pregnancy intake during the first 2 weeks of pregnancy, after w hich they were allowed to eat ad libitum. Rats in the second group wer e similarly restricted during the first 2 weeks, but beginning on day 14 of gestation were pair-fed to control rats until weaning on day 21 after birth. Such an experimental group was introduced because we obse rved that food-restricted mothers increased their food intake signific antly above control levels in the last week of gestation and maintaine d this increase into the first postnatal week, when they were returned to ad libitum feeding on day 14 of gestation. Control rats (third gro up) were given access to food ad libitum throughout pregnancy and lact ation. Offspring of mothers in the three groups are referred to as foo d-restricted/ad libitum refed (RA), food-restricted/pair-refed (RP) an d control (C) groups, respectively. From 6 weeks of age, RA males ate significantly more food and gained significantly more weight on a stan dard laboratory diet than control offspring. Maternal overeating after the restriction appears to be a necessary component in the aetiology of these effects because pair-refeeding mothers blocked the subsequent hyperphagia of male offspring fed the stock diet (RP group). In both the RA and RP groups, basal plasma glucose and insulin levels were not significantly different from those in control offspring and no altera tion of the tolerance to intravenous glucose and the in vivo insulin s ecretory response to glucose was detected. Moreover, glucose utilizati on and endogenous glucose production were not impaired when measured e ither in the basal situation (postabsorptive state) or in hyperinsulin aemic conditions. Therefore, early food restriction of the mothers exe rts no adverse effect upon insulin secretion and insulin action in the male offspring.