Swim training alters sympathoadrenal and endocrine responses to hemorrhage in borderline hypertensive rats

D. E. McCoy, J. E. Steele, R. H. Cox, R. L. Wiley

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Swim training alters cardiovascular, sympathoadrenal, and endocrine responses to hemorrhage in borderline hypertensive rats (BHR). The effects of 10, 20, and 30% blood volume hemorrhages on cardiovascular, sympathoadrenal, and endocrine function in swim-trained (T; 2 h/day, 5 day/wk for 10-12 wk) and age-matched, untrained, sedentary, control (UT) borderline hypertensive rats (BHR) were assessed. Heart rate (HR) in UT BHR was significantly greater during the baseline (rest) period than T BHR. HR increased slightly from baseline in both groups after 10% hemorrhage but was significantly decreased in both groups after 20 and 30% hemorrhages. The decrease was eliminated by atropine (1 mg/kg iv). Systolic (SBP) and diastolic (DBP) blood pressures decreased significantly after 20 and 30% hemorrhages in both T and UT BHR but were not different between the groups at these times. Plasma norepinephrine levels were significantly increased above baseline after 20 and 30% hemorrhages in UT BHR and were significantly greater in UT BHR than T BHR after 30% hemorrhage. Plasma glucose levels increased significantly after 30% hemorrhage in both groups but were significantly greater in UT BHR than T BHR. Both plasma norepinephrine and plasma epinephrine levels showed strong positive correlations with plasma glucose. After 20 and 30% hemorrhages, plasma insulin levels were unchanged in T BHR but were significantly decreased in UT BHR. Plasma insulin levels were significantly less in UT than T BHR after 30% hemorrhage. These results suggest that swim training alters the effect that hemorrhage exerts on endocrine and sympathoadrenal function in BHR. Moreover, fluid and electrolyte conservation in T BHR appears to be the result of less glucose mobilization and hence may conserve energy stores in response to hemorrhage.

Original languageEnglish (US)
Pages (from-to)R124-R130
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume269
Issue number1 38-1/II
DOIs
StatePublished - 1995

Keywords

  • catecholamines
  • epinephrine
  • exercise training
  • fluid conservation
  • insulin
  • norepinephrine

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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