Actions of salbutamol in late pregnancy: plasma cyclic AMP, insulin and C-peptide, carbohydrate and lipid metabolites in diabetic and non-diabetic women.

Salbutamol was administered intravenously in dose increasing from 3.75 to 22.5 microgram/min to 5 non-diabetic and 7 diabetic women in the last trimester of pregnancy. In diabetic as well as non-diabetic women the diastolic blood pressure fell progressively with increasing doses, and the systolic BP and heart rate increased at doses above 7.5 microgram/min. The effect of fetal heart rate was less pronounced than the effect on maternal heart rate. Cyclic AMP levels in plasma were similar in non-diabetic and diabetic women before salbutamol. Twenty min following 3.75 microgram/min a significant increase was seen in both groups. The peak increase (3-5 fold) was higher in the diabetic than in the non-diabetic women. Plasma insulin and C-peptide levels rose in a dose-dependent manner in the non-diabetic and four of the diabetic women. However, in three of the diabetic women the insulin level was unaffected by salbutamol and C-peptide was almost undetectable. Plasma concentrations of glucose, glycerol, NEFA and 3-HB were higher in the diabetics than in the non-diabetics before salbutamol and the elevations induced by salbutamol were also significantly larger in the diabetic women. The present data show that salbutamol in doses employed clinically may cause pronounced metabolic effects, especially in diabetic women, and it is suggested that when intravenous infusion of salbutamol is given to pregnant diabetic women not only cardiovascular but also some metabolic variable such as glucose should be carefully monitored.