Abstract
To assess the effects of pregnancy on secretory function in pancreatic alpha and beta cells, the following was studied during mid and late pregnancy and also 1 week and 4 weeks post partum. Glucose, insulin (IRI), C-peptide (CPR) and glucagon (IRG) were measured during basal condition and after oral challenge with glucose or intravenously with arginine. The carbohydrate metabolic function was classified following to the recommendatory criteria of Japan diabetic society and White's criteria.
Fasting values of IRI, CPR and IRG had a tendency to increase during pregnancy, which were smaller in the degree in diabetic. The CPR responses were sustained in diabetic, class A, but weak in class B, who were treated with exogenous insulin.
From mid to late pregnancy, values of CPR during glucose tolerance tests were significantly elevated, while IRI were slightly and not significantly elevated. At 1 week after delivery, both of IRI and CPR were significantly decreased, particularly in IRI, as compared to late pregnancy. From 1 week to 4 weeks after delivery IRI were slightly but significantly elevated despite of no change for CPR.
The incremental ratios ofserum IRI and CPR to glucose from fasting to 30 minutes after glucose administration were the highest in normal and the lowest in diabetic for pregnant and nonpregnant women.
In diabetic, fasting values of IRG were higher in post partum, but the degrees of these elevations during pregnancy were smaller as compared to normal.
IRI responses following 30 garginine infusion had two peaks at 5min. and 30min. The second peak level was lower in diadetic during pregnancy as compared to nonpregnant normal women. While IRG responses were not different between these two groups. But during and after delivery for same subjects, IRI and IRG responses were higher in 4 weeks and 1 week post partum, respectively.
From the results mentioned above, it is considered that alpha and beta cells of pancreas are loaded with physiological stimulation during pregnancy, which can be well tolerated in normal, but in diabetic tend to decrease the responseness to various metabolic stimuli. Peripheral insulin concentrations are influenced by altered metabolic conditions in liver and tissue during pregnancy. There are some differences of effects on alpha and beta cells between glucose and arginine during pregnancy.
