Hematologic and Plasma Biochemical Changes following Experimental Adrenal Insufficiency

Aim of the Study: The aim of this work is to study the hematologic effects of bilateral adrenalectomy in rats, especially on platelet function; and to relate the observed changes to the associated alterations in plasma biochemical parameters, also, to test the effects of replacement therapy by hydrocortisone. Materials and Methods: Rats were subjected to bilateral adrenalectomy (group I), sham-operated rats served as controls (group II). Blood samples were obtained from anaesthetized rats 48 hours after the operation. Hydrocortisone was given as a replacement therapy in another group for 48 hours after adrenalectomy (group III) and bled as the other groups. Results: Adrenalectomized rats showed increased values of PCV and MCV, and decreased MCHC. Other red cell parameters were not significantly changed. Leucocytes showed increased total count, increased percent of lymphocytes and a decrease in neutrophil percent. Biochemical measurements revealed significant increases in levels of plasma calcium and potassium; while values of plasma albumin and lipid parameters (total cholesterol and HDL-cholesterol) were not significantly changed from those seen in the sham-operated controls. Hydrocortisone treatment of adrenalectomized rats brought these hematological and biochemical changes to levels near to those observed in the sham-operated control group. Platelet aggregation: Adrenalectomized rats displayed inhibition of aggregation in response to both ADP and collagen, while treatment with hydrocortisone produced insignificant increase in platelet aggregation compared to adrenalectomized rats. Conclusion: Adrenal insufficiency produced inhibition of platelet aggregationinduced by both ADP and collagen. This inhibitory response was associated with raised plasma levels of calcium and potassium. The mechanism(s) of this inhibition of platelet aggregation in adrenalectomized rats is discussed.