Effects of pancreatectomy on the growth and metabolite concentrations of the sheep fetus.

The effects of fetal pancreatectomy on the growth and metabolism of the fetal sheep were investigated in chronically catheterized animals during the last third of gestation. Fetal pancreatectomy reduced body weight and crown-rump length at delivery near term (term 145 days). Body weight was affected more than body length so the ratio of weight to length was significantly less after pancreatectomy than in intact animals (P less than 0.05). Pancreatectomized fetuses appeared to maintain a normal growth rate for 5-10 days after surgery but thereafter showed no further significant increase in body weight. When all the data from the intact and pancreatectomized fetuses were combined, there was a significant positive correlation between the plasma insulin concentration in utero and the body weight at delivery near term. The majority of organs studied were reduced in absolute weight after pancreatectomy but only the spleen and thymus were proportionally lighter when the weights were expressed as a percentage of body weight. Brain and placental weights were similar in intact and pancreatectomized fetuses. Over the range of values observed in utero, there were significant inverse correlations between the log plasma insulin level and the mean plasma concentrations of glucose, lactate, fructose and alpha-amino-nitrogen in individual intact and pancreatectomized fetuses. Insulin infusion into pancreatectomized fetuses restored the metabolite concentrations to their normal values within 48 h of infusion. The results demonstrate that insulin has a vital role in regulating fetal growth and metabolism in utero.