Hyperglycemic Clamp Studies of Pancreatic Beta Cell Sensitivity in the Human Preterm Neonate

Abstract 1656 Neonatal Nutrition and Metabolism I Poster Symposium, Saturday, 5/1

Prior studies of the ontogeny of glucose homeostasis suggest that the neonate exhibits developing maturational control of endogenous glucose production (EGP). To study whether clinical hyperglycemia, observed in the human preterm neonate, may also in part be related to developing maturation of the pancreatic beta cell, we utilized the hyperglycemic clamp technique in conjunction with stable isotopic determination of glucose production and glucose utilization to measure pancreatic beta cell sensitivity to glucose. We performed the hyperglycemic clamp in 15 preterm neonates divided into three groups at three different glucose concentrations (i.e., 150, 200 and 250 mg/dl). The average birth weight of the neonates ranged from 1813±143 to 1913±97 grams (M±SEM). Gestational age ranged from 32±0.3 to 33±0.7 weeks. All neonates were studied in the first 4 days after birth. There were no significant differences in any of the demographic parameters or basal period measurements among the groups. The data for the hyperglycemic clamp period are listed in the Table. A metabolic steady state was achieved during both the basal and clamp periods in all neonates. There was a significant difference among the groups relative to the clamp glucose concentration (p<0.001). Although there was a difference in the clamp insulin concentration between the group clamped at 150 mg/dl and the other two groups, this difference did not reach statistical significance. No correlation was established between either clamp glucose concentration or clamp insulin concentration relative to the rates of glucose production or glucose clearance. There was a significant correlation between the clamp glucose concentration and clamp insulin concentration (R=0.61, p=0.016), as well as between the glucose infusion rate and clamp insulin concentration (R=0.57, p=0.026). These significant correlations suggest an adequate response to glucose by the pancreatic beta cell of the preterm neonate. However, due to the lack of significant stepwise increases in plasma insulin concentration in response to stepwise increases in plasma glucose concentration during the clamp, we speculate that the pancreatic beta cell response may not be optimal (i.e., mature) in the premature neonate.

Table 1 No caption available

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD