Contrasted impact of maternal rat food restriction on the fetal endocrine pancreas

The effects of food restriction of the mother (65% restriction of ad libitum food intake) on fetal and maternal insulin secretion and islet function were studied at 21 days gestation in three different rat populations: 1) undernourished from 0-7 days gestation, 2) undernourished from 7-14 days gestation, and 3) undernourished from 14-21 days gestation. The body weights of mothers were decreased in groups 2 and 3 vs. those in control fed pregnant animals, and no changes in basal parameters were found in any group. A glucose tolerance test in mothers from group 3 showed a mild intolerance to glucose and a decreased islet insulin content, although islet stimulation in vitro with glucose alone or plus arginine showed a normal insulin secretory response. Body weight was decreased in fetuses from the three groups (P < 0.01), and pancreas weight was reduced only in group 3. Insulinemia was increased in groups 2 and 3, and pancreatic insulin content increased only in group 3. However, fetuses from mothers of group 3 showed increased islet insulin content, in creased response of insulin in vitro to glucose or glucose 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 maternal changes to undernutrition seem to induce alterations on the fetal endocrine pancreas; especially when food restriction is applied during the last week of gestation.