Date of Award

7-30-1976

Degree Type

Thesis

University or Center

Atlanta University (AU)

School

School of Arts and Sciences

Degree Name

M.S.

Department

Biology

First Advisor

Dr. Joseph B. Myers

Abstract

The objectives of this research were to determine aldosterone concentration in the plasma and urine in rats with damaged adrenals and to ascertain whether impaired adrenals have an effect on the development of hypertension. Fifty male Sprague-Dawley rats (190-300 gm) were divided into three groups. Group I consisted of 10 adrenalectornized rats and 6 controls with both adrenals intact. Experimental rats in this group received 6 micrograms/rat/day of d-aldosterone—21-acetate injected intraperitoneally and 1.0% saline was given for drinking water. The controls received tap water ad libitum. Group II consisted of 5 rats with one-partially damaged adrenal (1-PDA) and the other adrenal gland was removed. Three controls had one adrenal gland intact and undamaged. Both experimental and control rats for this group received 1.0% saline for drinking water Group III consisted of 5 rats with both adrenals partially- damaged (2-PDA), and 3 controls with both adrenals undamaged. Experimental and control rats received 1.0% saline for drinking water daily. The adrenal glands in Groups II and III were damaged by cauterization using a Birtcher (Model 732) Hyfrecator. Sodium pentobarbital (Nembutal, 40 mg.kg) was used for the anesthetic agent and all operations were performed under aseptic conditions. Weight, blood pressures and 24-hr urines were taken at 7,15, and 30 days after the operations. The New England Nuclear protocol was used for the radioimmunoassay of aldosterone. The mean urine aldosterone values in groups I, II, and III (test rats) were 1.75, 2.40, and 1.55 ng/24 hr over the 30 day period. The mean urine aldosterone values in the controls were 1.40, 4.60 and 6.60 ng/24 hr respectively. These results show that the cauterization technique was possibly effective because the mean 30-day output of aldosterone was lower in the partially-damaged adrenals (1-PDA and 2-PDA) than in the respective controls. These findings support the fact that at 7 days the partially-damaged (1-PDA and 2-PDA) control animals were subjected to 1.0% saline as drinking water there was increased excretion of aldosterone with low urine sodium values, whereas at 15 and 30 days the 1-PDA and 2-PDA controls have low urine aldosterone values with elevated urine sodium levels. There was no significant increase in blood pressure over the 30-day period, which may suggest that impaired adrenal function might delay any gradual or rapid increase in blood pressure.

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