Fetuses from ten normal and twenty-two alloxan-diabetic rats removed by cesarean section at day twenty of pregnancy were compared with litter-mates removed at autopsy on day twenty-two.
In the normal group, granulated beta cells constituted 21.7 per cent of total islet cells at cesarean section and 27.9 per cent at autopsy.
Beta cells in fetal islets were markedly de granulated within two days after the initiation of hyperglycemia. One diabetic group was treated with adequate amounts of insulin to control hyperglycemia until cesarean section when insulin treatment was discontinued. This increased the blood sugar level from 203 to 333 mg. per 100 ml. and produced a decrease in granulated beta cells from 18.0 per cent at cesarean section to 6.7 per cent at autopsy. Vacuolated islet cells were 0.3 per cent at cesarean section and 0.4 per cent at autopsy.
Degranulated beta cells in fetal islets acquired granules within two days, if normoglycemia was established. A diabetic group was treated with inadequate amounts of insulin with an abrupt increase in dosage immediately after cesarean section. This caused a decrease in blood sugar level from 365 to 123 mg. per 100 ml. and led to an increase in granulated beta cells from 3.2 per cent at cesarean section to 38.3 per cent at autopsy. Vacuolated islet cells were 1.3 per cent of the total islet cells at cesarean section and 1.1 per cent at autopsy.