PII: S0022-3476(96)70224-X

Abstract

Reply to the Editor:Our finding that fetal hyperinsulinemia may be one the causes of neonatal macrosomia is in agreement with an earlier report by Procianoy and Cecin,1Procianoy RS Cecin SKG Insulin cord levels in large for gestational age infants born to non-obese, non-diabetic mothers.Acta Paediatr Scand. 1990; 79: 366-367Crossref PubMed Scopus (5) Google Scholar who measured insulin levels in the cord blood of macrosomic infants as pointed out in the letter above.However, in contrast to Procianoy, we measured C-peptide levels in the cord blood of macrosomic infants. Insulin, unlike C-peptide, has a variable clearance because up to 50% of secreted insulin could be extracted in the first pass through the hepatic portal circulation.2Horwitz DL Starr JI Mako ME Backard WG Rubenstein AH Proinsulin, insulin and C-peptide in human portal and peripheral blood.J Clin Invest. 1975; 55: 1278-1283Crossref PubMed Scopus (420) Google Scholar Insulin is also more subject to peripheral metabolism. C-peptide is believed to be a better index of pancreatic B-cell secretory activity than insulin. The correlation between C-peptide and insulin levels in the peripheral circulation is not always linear.3Faber OK Kehlet H Madsbad S Binder C Kinetics of human C-peptide in man.Diabetes. 1978; 27: 207-209Crossref PubMed Google ScholarWe reported that neonatal hypoglycemia developed in 20% of our neonates with macrosomia and hyperinsulinemia, as opposed to none in the Procianoy study. Finally, our study showed a correlation between cord blood C-peptide levels and birth weights.9/35/73311 Reply to the Editor:Our finding that fetal hyperinsulinemia may be one the causes of neonatal macrosomia is in agreement with an earlier report by Procianoy and Cecin,1Procianoy RS Cecin SKG Insulin cord levels in large for gestational age infants born to non-obese, non-diabetic mothers.Acta Paediatr Scand. 1990; 79: 366-367Crossref PubMed Scopus (5) Google Scholar who measured insulin levels in the cord blood of macrosomic infants as pointed out in the letter above.However, in contrast to Procianoy, we measured C-peptide levels in the cord blood of macrosomic infants. Insulin, unlike C-peptide, has a variable clearance because up to 50% of secreted insulin could be extracted in the first pass through the hepatic portal circulation.2Horwitz DL Starr JI Mako ME Backard WG Rubenstein AH Proinsulin, insulin and C-peptide in human portal and peripheral blood.J Clin Invest. 1975; 55: 1278-1283Crossref PubMed Scopus (420) Google Scholar Insulin is also more subject to peripheral metabolism. C-peptide is believed to be a better index of pancreatic B-cell secretory activity than insulin. The correlation between C-peptide and insulin levels in the peripheral circulation is not always linear.3Faber OK Kehlet H Madsbad S Binder C Kinetics of human C-peptide in man.Diabetes. 1978; 27: 207-209Crossref PubMed Google ScholarWe reported that neonatal hypoglycemia developed in 20% of our neonates with macrosomia and hyperinsulinemia, as opposed to none in the Procianoy study. Finally, our study showed a correlation between cord blood C-peptide levels and birth weights. Our finding that fetal hyperinsulinemia may be one the causes of neonatal macrosomia is in agreement with an earlier report by Procianoy and Cecin,1Procianoy RS Cecin SKG Insulin cord levels in large for gestational age infants born to non-obese, non-diabetic mothers.Acta Paediatr Scand. 1990; 79: 366-367Crossref PubMed Scopus (5) Google Scholar who measured insulin levels in the cord blood of macrosomic infants as pointed out in the letter above. However, in contrast to Procianoy, we measured C-peptide levels in the cord blood of macrosomic infants. Insulin, unlike C-peptide, has a variable clearance because up to 50% of secreted insulin could be extracted in the first pass through the hepatic portal circulation.2Horwitz DL Starr JI Mako ME Backard WG Rubenstein AH Proinsulin, insulin and C-peptide in human portal and peripheral blood.J Clin Invest. 1975; 55: 1278-1283Crossref PubMed Scopus (420) Google Scholar Insulin is also more subject to peripheral metabolism. C-peptide is believed to be a better index of pancreatic B-cell secretory activity than insulin. The correlation between C-peptide and insulin levels in the peripheral circulation is not always linear.3Faber OK Kehlet H Madsbad S Binder C Kinetics of human C-peptide in man.Diabetes. 1978; 27: 207-209Crossref PubMed Google Scholar We reported that neonatal hypoglycemia developed in 20% of our neonates with macrosomia and hyperinsulinemia, as opposed to none in the Procianoy study. Finally, our study showed a correlation between cord blood C-peptide levels and birth weights. 9/35/73311