STUDY OF THE EFFECT OF CROWDING STRESS ON ACID-BASE & ELECTROLYTE BALANCE AND IT'S RELATION TO CORTISOL CONCENTRATION IN RATS

Abstract

The aim of this study was to assess the effect of crowding stress on an important homeostatic mecharus•m including some hormones, which regulate the fluids volume, electrolytes concentrations that control a constant osmotic pressure at optimal pH (7.4). Sixty eight male albino rats (Sprague-Dawly strain), included in this study, were div ided into three age groups: young, adult, and senile. Each group was divided into control and experimental subgroups. Crowding stress was induced on all groups for 30 days. The results obtained in this study revealed that, the young crowded rats showed, as compared with their control group, a significant decrease in both sodium and aldosterone concentrations (p<0.05, p<O.OOOI, respectively) with a highly significant increase in cortisol concentration (p<O.OOO1). The adult crowded rats showed a highly significant decrease in sodium concentration (p<O.OOOI), an increase in aldosterone level (p< 0.0001) and a non significant change in cortisol concentration. Senile crowded group showed a significant decrease in both cortisol and aldosterone concentrations (p-sO.OOOl) and a non significant change in sodium concentration .On the other band, pH, pC02, p02, p50, TC0 2, ct02, total hemoglobin (tHb), s02%, bematocrite % (except for the hematocrite of the crowded young group which was significantly decreased (p<O.OOI) compared to its control group) actual base excess (ABE), standard base excess (SBE), standard base concentration (SBC), K+, and cr showed a non significant changes in all the crowded groups compared to their controls. Conclusion: crowding stress causes a profound impact on organism's healwhich gave specific responses in cortisol, aldosterone, and sodium levels that altered in the adult and young crowded group. However, the accurate homeostatic regulations of acid-base balance prevent the deviation of pH and acid-base status to sustain the life of the organism.