[Renal accumulation of radioiodinated alpha-1-microglobulin increases in the mononephrectomised rat]

Alpha-1-microglobulin (alpha 1M) is highly accumulated by the kidneys of normal rats. Aim of this study has been to verify if uninephrectomy can modify this behaviour. For this purpose the radioactivity of the remaining kidney and those of plasma and urine have been measured in uninephrectomized rats after IV injection of radioiodinated alpha 1M. The experiments have been performed in 100 Sprague-Dawley male rats. Fifty animals underwent right nephrectomy, the others being the controls. Uninephrectomized rats and their controls have been divided in 3 groups, studied 4, 14 and 28 days after surgery, respectively. All the animals were injected with human alpha 1M labelled with iodine-131. They were sacrificed in part 18 minutes after the injection of labelled alpha 1M (time of highest kidney accumulation in the normal rat), and in part 28 minutes after the injection. Uninephrectomy increased plasma retention of labelled alpha 1M. Kidney uptake (total and per gram) was always higher in uninephrectomized animals. Similarly, urine radioactivity was higher in uninephrectomized rats. These results demonstrate that uninephrectomy remarkably increases the accumulation of alpha 1M in the remaining kidney.