Effect of Age and Thyrocalcitonin on Myocardial Changes Induced by Sodium Sulfaacetylthiazole

Abstract

SYNOPSISNa-sulfaacetylthiazole, 0.5g/kg body weight, was injected into immature and adult rats to produce obstructive nephropathy. Necrotic changes in the myocardium were found in all of the 9 adult rats of about 120days of age, whereas no such changes occured in immature animals of about 40days of age. Thyrocalcitonin, 50 mMRC units a day injected subcutaneously for one week, completely inhibited the occurrence of such myocardial lesion in adult animals, as did parathyroidectomy performed one week previously. Serum calcium was decreased from the normal adult level in thyrocalcitonin treated or parathyroidectomized animals but not in untreated immature rats. Thyrocalcitonin appears to have some effect on cardiovascular system in addition to the known effect on the bone.

Age and Calcium Metabolism in Relation to Cardiovascular Changes Induced by Renal Injury with Sodium Sulfaacetylthiazole

“…The effect of parathyroidectomy in preventing these SAT‐induced cardiovascular changes has been demonstrated histologically by Lehr (1), who pointed out the importance of age and calcium metabolism in the development of such lesions. Fujita et al (2) in 1968 showed histologically the preventive effect of age and thyrocalcitonin in addition to that of parathyroidectomy, with respect to these SAT‐induced cardiovascular changes.…”

“…In view of the definite preventive effect of parathyroidectomy on SAT‐induced cardiovascular changes, thyrocalcitonin may be expected to antagonize the action of parathyroid hormone by inhibiting bone resorption which might be followed by metastatic calcification. Fujita et al (2) reported that 50 mrc mu of thyrocalcitonin was effective for the prevention of SAT‐induced cardiovascular changes, based on histological study. In our series, however, daily administration of 200 mrc mu of thyrocalcitonin prevented only the increase of calcium in the heart, and had no preventive effect on the accumulation of 45 Ca in soft tissues or on arterial calcification and myocarditis in SAT‐treated adult animals.…”

“…Fujita et al (2), following Lehr (1), reported that aged animals are more liable to the development of SAT‐induced cardiovascular changes as compared with immature animals. Such an effect of age on the occurrence of SAT‐induced cardiovascular changes was confirmed by the use of 45 Ca as well as by morphological study.…”

“…In 1959 Lehr (1) reported the preventive effect of parathyroidectomy on the cardiovascular changes induced by administration of sodium sulfaacetylthiazole (SAT) and pointed out the importance of calcium metabolism in such changes. Based on our own observations on the importance of both age and calcium metabolism in such cardiovascular alterations (2), we used 45 Ca for the study of the dynamic aspects of this calcium metabolism in more detail.…”