Maternal undernutrition during the periconceptual period increases plasma taurine levels and insulin response to glucose but not arginine in the lategestation fetal sheep.

Maternal undernutrition throughout gestation impairs pancreatic function in the offspring. The influence of periconceptual maternal undernutrition on fetal insulin responses to secretogues in late gestation is unknown. Romney ewes were fed concentrates at 1-2% of body weight/d (UN) or 3-4% of body w eight/d (N) from -61d to +30d from mating. From 30d gestation all ewes were fed at 3-4% of body weight/d. At 119d gestation singleton fetuses (UN, n=1 2, N; n=10) underwent intravenous glucose (1.5g) and arginine (300mg) chall enge tests. Paired maternal and fetal blood samples were collected over 60m in. Fetal plasma insulin area under the curve (AUC) was larger in UN than i n N fetuses during glucose challenge (4.5 +/-0.6 vs. 2.9 +/-0.5nM, p <0.05) but was not different during arginine challenge. Maternal and fetal plasma taurine concentrations were higher in UN than N (maternal; 110 +/- 11 vs 7 5 +/-8 muM, fetal; 99 +/- 13 vs 56 +/-5 muM, both p<0.05). Maternal pericon ceptual. undernutrition influences fetal insulin secretion without affectin g fetal size. The larger plasma insulin responses in UN fetuses could refle ct accelerated maturation of pancreatic <beta> cells or an alteration of ot her mechanisms regulating insulin secretion. The role of taurine in fetal p ancreatic beta cell development requires further investigation.