Experimental Studies on the Relationship between Endocrine Organs and Hypertension in Spontaneously Hypertensive Rats

Abstract

In spontaneously hypertensive rats (Okamoto and Aoki) effects of various hormones on blood pressure of the animals, whose endocrine organ had been removed and which had maintained normotension, were investigated. The administration of ACTH, cortisone or thyroid powder to animals showing normotension after hypophysectomy increased the blood pressure up to the hypertensive range, but it was lower than that before hypophysectomy. Vasopressin had no such effect. The administration of cortisone or DCA (desoxycortico sterone acetate) to animals showing normotension after adrenalectomy increased the pressure up to the hypertension range. The administration of thyroid powder slightly raised the blood pressure. Aldosterone and vasopressin had no such effect. The administration of the thyroid powder to animals showing normotension after thyroidectomy raised the blood pressure up to the hypertension range. Cortisone and DCA had no effect on blood pressure. The pituitary hypertensive factors are considered to be ACTH and TSH (thyroid stimulating hormone). The adrenal hypertensive factors are chiefly cortisone-like hormones and the thyroid hypertensive factor is the thyroid hormone. Hypofunction of the thyroid and the adrenals inhibits the development of hypertension and also lowered the blood pressure to the normal range. The maintenance of these functions are indispensable for the maintenance of hypertension. Their hyperfunction produces and enhances the hypertension. These functions are presumably controlled by ACTH and TSH from the pituitary.