INSULIN-INDUCED HYPOGLYCAEMIA IN DIABETIC WOMEN DURING LATE PREGNANCY AND ONE YEAR POST PARTUM

Summary

Insulin (0·1 IU/kg) later followed by glucose was injected intravenously in nine diabetic women in the supine position both during pregnancy and one year post partum. C-peptide was present in five subjects, indicating some residual (β-cell function. Their mean basal C-peptide level, before insulin, was twice as high in the pregnant as in the non-pregnant state. C-peptidedecreasedprogressivelyafterinsulin. The mean basal plasma glucose level was lower during pregnancy (4·8 mmol/l) than after it (9·6 mmol/l), but decreased to the same level (2·2 mmol/l) after insulin. The rate of fall in glucose was thus lower during pregnancy (k_t= 2·54) than after (k_t= 4·08), but was unrelated to the basal glucose levels. Basal levels of free fatty acids (FFA), 3-hydroxybutyrate (3-HB), cyclic AMP, and lactate were similar, while glycerol was lower during pregnancy. Insulin-induced changes in FFA, glycerol, 3-HB, cyclic AMP, and lactate were similar during and after pregnancy. Plasma amino acid concentrations were generally lower in pregnancy, significantly so only for arginine and glycine. Amino acid levels were unaffected by insulin in pregnancy, whereas leucine, isoleucine and tyrosine decreased significantly in the non-pregnant state. We conclude that there are differences in metabolic responses to insulin in diabetic women during and after pregnancy, indicating a decreased sensitivity to insulin during pregnancy in some tissues.