[Thyroxine treatment in acute renal failure (author's transl)]

8 patients suffering from acute renal failure (shock kidney) with anuria extending over 3 to 5 days, were treated with L-thyroxine for 5 to 9 days (5-6 mug per kg body weight per day orally). Diuresis was restored within 34 to 46 hrs. Plasma levels of urea and creatinine decreased earlier and much more rapidly to normal than was to be expected from the natural history of the disease, indicating the prompt and extensive increase of glomerular filtration rate. Polyuria seemed less pronounced and also shortened as compared with the ordinary course of that form of sudden renal insufficiency. Obviously, the well-known diuretic response in the normal individual to high doses of thyroid hormones in not a factor in the induction of diuresis in acute renal failure. The tendency with L-thyroxine treatment to dilate the preglomerular arterial vessel is considered a consequence of the stimulation of sodium reabsorption in the upper nephron. High values of RPF and GFR, regularly observed in hyperthyroidism or after L-thyroxine administration, do not depend on any augmentation of cardiac output or on arterial hypertension, since such symptoms were missed in our patients and, in our view, such an interpretation is excluded by the very existence of the so-called autoregulation of the kidney which leaves RPF (and therefore GFR) independent of systemic blood pressure. The same intrarenal feed-back mechanism, normally adapting the glomerular blood supply to the resorptive capacity of the proximal-tubular epithelium (mediation via the juxta-glomerular apparatus), is responsible for the GFR- and RPF-raising effect of exogenous L-thyroxine in the intact kidney as well as in acute renal failure: both sodium reabsorption and sodium filtration are accelerated.--The special conditions under which L-thyroxine interferes with the pathogenetic process of acute renal failure, the latter being characterised by the critical insufficiency of tubular sodium reabsorption and therefore by preglomerular arterial constriction, is discussed on the basis of a new hypothesis concerning the thyrogenic nephrotropic effects in general.