[Binding of aldosterone to its receptors along the nephron of the normal and spontaneously hypertensive rat].

The specific binding of aldosterone has been investigated using an autoradiographic method, on isolated tubular segments of kidneys from spontaneously hypertensive (SHR) and normotensive (KWR) Okamoto rats, and normotensive Wistar (NWR) rats. A low, mineralocorticoid, concentration of aldosterone (2 X 10(-9) M) was used. In proximal tubules, almost no specific labelling was found in the three groups. In the cortical ascending limb, a specific nuclear labelling was present and equivalent in the three groups. In the distal (DCT) and cortical collecting (CCT) tubule, the specific labelling was double in SHR and KWR than in NWR. This higher binding capacity occurs in target segments for aldosterone, and coincides with the increased sodium reabsorption in the distal structures of Okamoto rats, previously reported by our laboratory. The relations between these observations and the altered membrane permeability described in hypertensive disease is discussed.