Submitted to: Diabetes Care
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/30/1998
Publication Date: N/A
Citation: Interpretive Summary: About 5 percent of all pregnancies are affected by a maternal disorder called gestational diabetes mellitus (GDM), involving high blood glucose and amino acid levels. In response the fetus may develop hyperinsulinemia, or too much insulin, which can promote excessive growth. Conventional dietary and insulin therapy have not totally resolved this problem. We theorized that protein metabolism is not totally normalized in insulin-treated GDM patients, and examined the protein turnover and plasma amino acid concentrations of a group of these women. We found their protein turnover was normalized, but their plasma amino acid levels were elevated. We therefore think that these high amino acid levels may promote fetal hyperinsulinemia and high birth weights. Earlier diagnosis, treatment, and preventive measures to improve insulin sensitivity in women predisposed to GDM may be required to fully normalize protein metabolism in GDM patients. This information should prove very helpful in resolving a problem that affects a significant number of pregnancies.
Technical Abstract: We tested the hypothesis that protein metabolism is not totally normalized in insulin-treated gestational diabetes mellitus (GDM) patients compared with normal, pregnant controls. Protein metabolism in 8 Hispanic women with insulin-treated GDM and 8 healthy Hispanic controls was studied in late gestation and at 6 wk postpartum. Nitrogen flux was assessed from the disposal rate of 15N urea over 12 h after a dose of 15N-labeled leucine. Plasma amino acid concentrations were determined in fasting and 2-h postprandial samples using an amino acid analyzer. Protein turnover was normalized in insulin-treated GDM, however, fasting and postprandial plasma amino acids were elevated antepartum and postpartum. Nitrogen flux was significantly lower during pregnancy (P=0.04-0.001), and did not differ between groups. Fasting and postprandial plasma amino acids were elevated in GDM antepartum and postpartum, despite satisfactory glycemic control. Fasting levels of taurine, hydroxyproline, glutamic acid, glutamine, cystine, tyrosine, phenylalanine, tryptophan, and histidine were higher in GDM antepartum and postpartum (P<0.05). Postprandial concentrations of taurine, hydroxyproline, valine, cystine, isoleucine, leucine, tyrosine, phenylalanine, tryptophan, ornithine, lysine, histidine, and arginine were higher in GDM antepartum and postpartum (P<0.05). With few exceptions, plasma amino acid concentrations were lower antepartum than postpartum (P<0.05). We conclude that elevated plasma amino acids may promote fetal hyperinsulinemia and growth, despite satisfactory maternal glycemic control. Complete normalization of protein metabolism in GDM may require earlier diagnosis and initiation of treatment, and preventative measures to improve insulin sensitivity in women predisposed to GDM.