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

Various hormones were administered to spontaneously hypertensive (Okamoto and Aoki) and normotensive rats and their blood pressure and body weight were measured.(1) In spontaneously hypertensive rats vasopressin, pitressin, aldosterone, noradrenaline and diethylstilben had no effect on their blood pressure. Cortisone and thyroid powder accelerated the development of hypertension and enhanced hypertension. DCA enhanced hypertension. Testosterone had a tendency to increase the blood pressure in males, progesterone lowered it in females and estradiol decreased in both males and females.(2) In normotensive rats ACTH had a slight tendency to increase blood pressure. Cortisone, DCA and thyroid powder developed hypertension. Radiothyroidectomy had a slight tendency to lower blood pressure but they remained within normal range.(3) Excessive humoral state of thyroid (thyroxin) and adrenal cortical hormones (cortisone and DCA) by their administration developed and enhanced hypertension. If hypertrophy of the pituitary, adrenal and thyroid glands can be regarded as a demonstration of their hyperfunction, it may be concluded that the pituitary secretes excess amount of ACTH and TSH and makes the target organs secrete excess amount of their hormones. In this way the adrenal and thyroid showed hyperfunction, which plays one of the important etiological roles in the development and maintenance of hypertension.The outline of this study was reported at the symposium of 35th annual meeting of the Japanese Endocrinological Society in 1962 and at the 51st annual meeting of the Japanese Pathological Society in 1962.