Swim training alters sympathoadrenal and endocrine responses to hemorrhage in borderline hypertensive rats (bhr). McCoy, David E., Janet E. Steele, Ronald H. Cox, and Ronald L. Wiley. Departments of Zoology and Physical Education, Health and Sports Studies, Miami University, Oxford, Ohio 45056
APStracts 2:0043R, 1995.
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; 2hr/day, 5day/wk for 10-12 weeks) 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 following 10% hemorrhage but was significantly decreased in both groups following 20% and 30% hemorrhages. The decrease was eliminated by atropine (1 mg/kg, i.v.). Systolic (SBP) and diastolic (DBP) blood pressures decreased significantly following 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 following 20% and 30% hemorrhages in UT BHR and were significantly greater in UT BHR than T BHR following 30% hemorrhage. Plasma glucose levels increased significantly following 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. Following 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 BHR than T BHR following 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. 

Received 31 May 1994; accepted in final form 7 February 1995.
APS Manuscript Number R291-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.