CONTRASTED IMPACT OF MATERNAL RAT FOOD RESTRICTION ON THE FETAL ENDOCRINE PANCREAS

The effects of food restriction of the mother (65% restriction of ad l ibitum food intake) on fetal and maternal insulin secretion and islet function were studied at 21 days gestation in three different rat popu lations: 1) undernourished from 0-7 days gestation, 2) undernourished from 7-14 days gestation, and 3) undernourished from 14-21 days gestat ion. The body weights of mothers were decreased in groups 2 and 3 vs. those in control fed pregnant animals, and no changes in basal paramet ers were found in any group. A glucose tolerance test in mothers from group 3 showed a mild intolerance to glucose and a decreased islet ins ulin content, although islet stimulation in vitro with glucose alone o r plus arginine showed a normal insulin secretory response. Body weigh t was decreased in fetuses from the three groups (P < 0.01), and pancr eas weight was reduced only in group 3. Insulinemia was increased in g roups 2 and 3, and pancreatic insulin content increased only in group 3. However, fetuses from mothers of group 3 showed increased islet ins ulin content, in creased response of insulin in vitro to glucose or gl ucose plus arginine, and hypertrophy of beta-cell mass. These results indicate, first, that the development of the fetal pancreas depends on a balanced maternal glucose homeostasis and, second, that adaptive ma ternal changes to undernutrition seem to induce alterations on the fet al endocrine pancreas; especially when food restriction is applied dur ing the last week of gestation.