Elevated plasma norepinephrine inhibits insulin secretion, but adrenergic blockade reveals enhanced β-cell responsiveness in an ovine model of placental insufficiency at 0.7 of gestation

A. R. MacKo, D. T. Yates, X. Chen, A. S. Green, A. C. Kelly, L. D. Brown, S. W. Limesand

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

In pregnancies complicated by placental insufficiency (PI), fetal hypoglycemia and hypoxemia progressively worsen during the third trimester, which increases circulating norepinephrine (NE). Pharmacological adrenergic blockade (ADR-block) at 0.9 gestation revealed that NE inhibits insulin secretion and enhanced β-cell responsiveness in fetuses with PI-induced intrauterine growth restriction (IUGR). NE concentrations in PI fetuses at 0.7 gestation were threefold greater compared with age-matched controls, but the levels were similar to near-term controls. Therefore, our objective was to determine whether elevations in plasma NE concentrations inhibit insulin secretion and produce compensatory β-cell responsiveness in PI fetuses at 0.7 gestation. Fetal insulin was measured under basal, glucose-stimulated insulin secretion (GSIS) and glucose-potentiated arginine-stimulated insulin secretion (GPAIS) conditions in the absence and presence of an ADR-block. Placental weights were 38% lower (P < 0.05) in PI fetus than in controls, but fetal weights were not different. PI fetuses had lower (P < 0.05) basal blood oxygen content, plasma glucose, insulin-like growth factor-1 and insulin concentrations and greater plasma NE concentrations (891 ± 211 v. 292 ± 65 pg/ml; P < 0.05) than controls. GSIS was lower in PI fetuses than in controls (0.34 ± 0.03 v. 1.08 ± 0.06 ng/ml; P < 0.05). ADR-block increased GSIS in PI fetuses (1.19 ± 0.11 ng/ml; P < 0.05) but decreased GSIS in controls (0.86 ± 0.02 ng/ml; P < 0.05). Similarly, GPAIS was 44% lower (P < 0.05) in PI fetuses than in controls, and ADR-block increased (P < 0.05) GPAIS in PI fetuses but not in controls. Insulin content per islet was not different between treatments. We conclude that elevations in fetal plasma NE suppress insulin concentrations, and that compensatory β-cell stimulus-secretion responsiveness is present before IUGR.

Original languageEnglish (US)
Pages (from-to)402-410
Number of pages9
JournalJournal of Developmental Origins of Health and Disease
Volume4
Issue number5
DOIs
StatePublished - Oct 2013

Keywords

  • Key words adrenergic receptors
  • fetus
  • intrauterine growth restriction
  • pancreas

ASJC Scopus subject areas

  • Medicine (miscellaneous)

Fingerprint Dive into the research topics of 'Elevated plasma norepinephrine inhibits insulin secretion, but adrenergic blockade reveals enhanced β-cell responsiveness in an ovine model of placental insufficiency at 0.7 of gestation'. Together they form a unique fingerprint.

Cite this