The role of alcohol or caffeine drinking habit, dietary salt and life event stresses in the precipitation of hypertension is often described in clinical studies. Parallel studies on laboratory animals are indicative of various hormonal regulations (like catecholamines and rennin angiotensin system) and Na+-K+- ATOase. The contribution of electrolytes in the aetiology and treatment of hypertension has been established both in man and experimental animals.
The present study concerns sex related differences of electrolyte homeostasis in various induced forms of hypertension in rats which may be relevant the greater occurrence of hypertension in men than women
The main findings are as follows:
1.50 days chronic but not single acute administration of ethanol produced hypertension in rats and this associated with an increased sodium and potassium in red cells, decreased calcium in heart and kidney tissues. Chronic ethanol induced hypertension and changes in red cell and tissue electrolytes were greater in male than female rats
2. Caffeine given in acute doses of 2mg/kg increased systolic blood pressure in rats, given chronically in drinking water the drug did not significantly effect systolic blood pressure. The caffeine-induced hypertension was greater in male rats and associated with increased sodium content of red cell, heart and kidney tissue, an increased calcium in heart and kidney tissue and decreased sodium, potassium, calcium and magnesium in plasma. These changes were also greater in male than female rats
3. Acute and four weeks chronic administration of NaCI increased blood pressure in male and female rats. The increases after chronic administration was more pronounced and greater in male than corresponding female rats. Salt induced hypertension was associated with an increased sodium and decreased potassium in red cell heart and kidney tissues, increased calcium and decreased magnesium in plasma, heart and kidney tissues. The changes of electrolytes were greater in male than female rats.
4. Both acute and repeated immobilization stress elevated blood pressure more in male than female rats. The stress induced blood pressure were associated with increased sodium in red cell heart and kidney tissues, decreased potassium in red cell, increased magnesium and decreased calcium in plasma, increased calcium and decreased magnesium in heart and kidney tissues. The changes of electrolytes were greater in male than female rats
The results may help towards an understanding of relationship between hypertension and electrolyte homeostasis. A possible role of hormonal changes and activity of Na+-K-+ ATOase leading to the observed changes of electrolytes or vice versa is discussed. The findings suggest that a greater effect of alcohol, caffeine, salt and stress on particularly red cell and tissue sodium and calsium may put male sex at a greater risk to hypertension