[Experimental study on diabetes and pregnancy: with special reference to the effects of insulin treatment on fetuses of diabetic dams].

: Through the development of treatment of diabetes mellitus, diabetic cases of pregnancy have been increasing, and the effects of maternal hyperglycemia and insulin-treated hypoglycemia on the growth and life of fetuses and newborns are becoming very important problems. However, it is difficult for us to investigate the fetuses of human diabetic mothers as experimental models. Although many reports deal with the development of newborns of diabetic mothers and about their secretory changes of insulin and C-peptide reactivity, there have been few reports concerning the effects of severe diabetes on pregnancy and the effects of insulin treatment on fetuses. Concerning experimental animals, there are also few reports about the effects of insulin treatment on diabetic pregnant animals. We conducted the present investigation to determine the effects of insulin treatment on the growth and metabolism of the fetuses of diabetic pregnant rats. Virgin female Wistar rats weighing 200 approximately 300 g were caged overnight with male rats. The mated females were isolated and the gestational age was calculated from noon of this day (zero). Seventeen of 24 pregnant rats received a rapid intravenous injection of 50 mg/kg body weight of streptozotocin (STZ) in 0.4 ml of 0.01 M citrate buffer (pH 4.5) immediately after blood samples were collected through the jugular vein under light ether anaesthesia on the 5th day of gestation. Seven pregnant rats were injected with only 0.4 ml of citrate buffer and served as the controls. These rats were divided into four groups, and each group was named as follows: Normal pregnant rats group (group I, n = 7), diabetic pregnant rats group (group II, n = 6) and insulin-treated diabetic pregnant rats group (group III: plasma glucose level 60 approximately 300 mg/dl, n = 6 and group IV: plasma glucose level below 60 mg/dl, n = 5). Group III and IV rats were treated with a subcutaneous injection of Lente Insulin (from 2 u. to 6 u.) every day from the 13th to the 19th day of gestation. Group II rats were injected with saline every day in the same way. Maternal blood samples were collected under light ether anaesthesia after feeding ad libitum on the 5th and 12th days of gestation. On the 20th day of gestation, the pregnant rats were anaesthetized by an intraperitoneal injection of sodium pentobarbital, and blood samples were collected in the manner stated above. Each fetus and placenta was taken out individually by hysterotomy.(ABSTRACT TRUNCATED AT 400 WORDS)