Age-related differences in the pancreatic β-cell response to hyperglycemia after eccentric exercise

Raj K. Krishnan, Jazmir M. Hernandez, David L. Williamson, Donal J. O'Gorman, William J. Evans, John P. Kirwan

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

Eccentric exercise (ECC) causes muscle damage, insulin resistance, and increased pancreatic β-cell secretion in young individuals. However, the effects of age on the pancreatic β-cell response to glucose after ECC are unknown. Hyperglycemic clamps (180 min, 10.0 mM) were performed on eight young (age 22 ± 1 yr) and eight older (age 66 ± 2 yr) healthy sedentary males without exercise (CONT) and 48 h after ECC. ECC increased (P < 0.02) muscle soreness ratings and plasma creatine kinase concentrations in both groups. Insulin and C-peptide secretions were similar between young and older subjects during CONT clamps. ECC increased (P < 0.05) first-phase (0-10 min) C-peptide area under the curve in young (4.2 ± 0.4 vs. 317 ± 0.6 nM · min; ECC vs. CONT, respectively) but not in Older subjects (3.2 ± 0.7 vs. 3.5 ± 0.7 nM · min; ECC vs. CONT), with significant group differences (P < 0.02). Indeed, ECC repressed (P < 0.05) first-phase peak C-peptide concentrations in older subjects (0.93 ± 0.16 vs. 1.12 ± 0.11 nM; ECC vs. CONT). Moreover, first-phase C-peptide-to-insulin molar ratios suggest age-related differences (P < 0.05) in insulin/C-peptide clearance after ECC. Furthermore, the observed C-peptide response after ECC was related to abdominal adiposity [r = -0.62, P < 0.02, and r = -0.66, P < 0.006, for first and second (10-180 min) phases, respectively]. In conclusion, older individuals did not exhibit the compensatory increase in β-cell secretion observed among young individuals after ECC. Thus, with increasing age, the pancreatic β-cell may be less responsive to the physiological stress associated with ECC.

Original languageEnglish (US)
Pages (from-to)E463-E470
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume275
Issue number3 38-3
DOIs
StatePublished - Sep 1998

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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