Effect of pregnancy on the glucagon response to protein ingestion

Plasma glucose, insulin and glucagon concentrations were measured before and after the ingestion of a protein-rich meal in 11 healthy pregnant women in the last trimester of pregnancy, and again in the same subjects postpartum. Compared to postpartum, basal levels of plasma glucose were lower in late pregnancy whereas basal insulin and glucagon concentrations were both enhanced. After the meal, insulin and glucagon concentrations in plasma increased in gestation as well as postpartum. Plasma glucose increased slightly in pregnancy but remained unchanged postpartum. The mean insulin response to the meal was unaffected by pregnancy whereas that of glucagon was reduced. Thus following protein ingestion, plasma glucose rose in pregnancy in spite of unchanged levels of insulin and depressed levels of glucagon. Favouring analbolism, the reduced glucagon response to protein ingestion in pregnancy fits in the concept of 'facilitated anabolism' in late pregnancy and, moreover, it lend further support to the idea that changes in glucagon secretion per se are not involved in the pathogenesis of the diabetogenicity of pregnancy.