Maintenance of Arterial Pressure by Vasopressin and Angiotensin II after Adfenalectomy

ELUOVICH, FERNANDO M.D.
KIRCHBERGER, MADELEINE PH.D.
BARRY, CATHERINE R. M.S.
KRAKOFF, LAWRENCE R. M.D.

Hypertension Division, Department of Medicine and Department of Physiology, Mount Sinai School of Medicine, New York, New York.

Address for reprints: Fernando Elijovich, M.D., Assistant Professor of Medicine, Mount Sinai School of Medicine, Annenberg 23–32, One Gustave L. Levy Place, New York, NY 10029.

Supported in part by a New York Heart Association Research Fellowship.

Hypertension 5(6):p V53-V56, November-December 1983.

SUMMARY

Participation of vasopressin arid the renin-anglotensin system in the maintenance, of systemic arterial pressure was evaluated in unanesthetized adrenalectomized rats. Adrenalectomized and sham-operated rats with implanted arterial and venous catheters were given 1% sodium chloride and 2.5% glucose as drinking fluid for 72 hours following adrenalectomy. Serum and urine samples were obtained for measurement of electrolyte and solute concentration. The pattern of serum electrolytes, serum osmolality, and renal excretion of electrolytes, solute, and water observed in the adrenalectomized rats was entirely consistent with previous observations in this model. Mean arterial pressure of unanesthetized unrestrained adrenalectomized rats was significantly lower than controls. In adrenalectomized rats, dPMeTyrAVP reduced mean arterial pressure 9 ± 1 mm Hg, p < 0.001; captopril then caused an additional reduction of 17 ± 2 mm Hg, p < 0.01. Neither antagonist altered arterial pressure in the control group. Our results indicate that vasopressin and the renin-angiotensin system play a compensatory pressor role in adrenal insufficiency, preventing a larger decrease of arterial pressure in this model of chronic hypotension.