Sites of aldosterone-induced hyperplasia along the nephron and collecting ducts

Sites of aldosterone-induced hyperplasia along the nephron and collecting ducts. The mitotic activity was separately measured in 12 segments of the nephron and collecting ducts in intact and adrenalectomized rats, injected with aldosterone for two or five days, with daily doses of 0, 10, 20, 40 and 80 micrograms. Stimulation of the mitotic activity was observed in the proximal convoluted tubules, the deep straight distal tubules and in the collecting ducts in the same layer as that containing deep straight tubules (medulla externa interna). Adrenalectomy depressed the mitotic activity in the straight distal tubules and, after 6 days, stimulated it in the proximal convoluted tubules. Adrenalectomy also induced morphological change in these two segments. Apart from the collecting ducts, which have already been recognized as a target for aldosterone, this paper points to another probable target for this hormone: namely the straight distal tubule.