Comparison of the Effects of ‘Glucocorticoid’ And ‘Mineralocortocoid’ Infusions on Blood Pressure in Sheep

Abstract

It is generally believed that adrenal steroid hypertension is due to the ‘mineralocorticoid’ and/or ‘glucocorticoid’ activities of the steroid(s). The present study examines the blood pressure and metabolic effects of steroid hormone infusion in intact conscious sheep to assess the relative contributions of ‘glucocorticoid’ and ‘mineralocorticoid’ activity.Cortisol at 5 mg/h increased mean arterial pressure (MAP) but the effect was small (MAP + 10 mm Hg on day 5). This rate of infusion produces blood cortisol levels appropriate for maximal ACTH stimulation. Cortisol at 20 mg/hr produced hypertension (MAP + 25 mm Hg on day 5, p lt;0.01) but also produced the ‘mineralocorticoid’ effect of severe hypokalaemia.