ELIMINANT EFFECTS OF CALCITONIN-GENE-RELATED PEPTIDE ON THE TUBULAR EPITHELIAL-CELLS IN AN ISOLATED AND PERFUSED RAT-KIDNEY

The effect of the infusion of calcitonin gene related peptide (CGRP) o n the renal structure and enzyme release from tubular epithelial cells was studied. This study was performed in the model of an isolated per fused kidney to avoid the systemic effects and complex hormonal and ne uromediated interaction following the CGRP infusion in the intact expe rimental animal. After infusion of CGRP, the perfused kidney, studied by semiquantitative histology and electron microscopy, did not show an y alteration at the glomerular level; however, important histological lesions were apparent at the proximal tubular level: the brush border was destroyed and the epithelial cells were markedly flattened. This s tructural damage to epithelial cells was confirmed by electron microsc opy. The alanine amino peptidase (AAP) and N-acetyl-glucosaminidase (N AG) were significantly increased in the effluent of the perfusion syst em, in confirmation of the histological damage. The direct toxic effec t of CGRP on the tubular epithelial cells may be related to the reabso rption and tubular transport of this substance.