Hematologic and plasma btochemical changes following experimental adrenal insufficiency

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. 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 Ill] and bled as the other groups. 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. Adrenal insufficiency produced inhibition of platelet aggregation- induced 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

Cardiovascular risk factors in L-NAM E hypertension

In a previous study, hypertension was induced by administration of L-NAME for 1, 2 and 4 weeks. Hypertension was prevented when L-NAME was combined with L-arginine but not with dipyridamole. To study the changes in ECG, cardiac weights and plasma lipids associated with L-NAME hypertension. Wistar rats were allocated into a control group, 3 groups of rats that received L-NAME [20 mg/kg] for 1, 2 and 4 weeks, and 2 other groups that received L-NAME in the same dose for 2 weeks combined with L-arginine [40mg/kg] or dipyridamole [3mg/ kg]. The absolute weight of left ventricle [LV] and whole heart [WH] were significantly increased in L-NAME 4 weeks group, but such significant increase was lost when corrected for body weight [LV/BW and WH/BW]. In L-NAME and L-arginine 2 weeks group, there was no change in absolute or relative weights, whereas in the L-NAME and dipyridamole 2 weeks group, there was significant decrease in LV, WH and LV/BW. Concerning ECG parameters, there was no significant difference amongst control group and L-NAME I, 2 and 4 weeks groups as regards P-R interval, QRS complex and R-wave voltage. Both Q-To and Q-Tc intervals were significantly shortened in L-NAME 4 weeks group than control, L-NAME I week and 2 weeks groups. In L-NAME and L-arginine 2 weeks group, P-R interval was significantly shorter than control group. Also, L-NAME and dipyridamole 2 weeks group showed significant in R wave voltage than control and L-NAME 2 weeks groups. Treatment for 2 weeks with L-arginine or dipyridamole shortened Q-To and Q-Tc than control or L-NAME 2 weeks groups. In NAME-treated rats for I, 2 and 4 weeks, there was no significant changes in plasma levels of total cholesterol, HDL-cholesterol and LDL- cholesterol, nor atherogenic index or triglycerides. L-NAME hypertension up to 4 weeks duration was not associated with cardiac hypertrophy or ECG changes. Also, the lipid profile was not significantly modified from the normal pattern