Figure 5: Tubulogenic effect of aldosterone after a 13 days culture period depended on applied hormone concentration. Histochemistry on cryosections showed that control without aldosterone administration lacked SBA-labeled cells and tubules. (a) A low dose of 1 x 10-10 M aldosterone did not show SBAlabel cells. (b) Administration of 1 x 10-9 M aldosterone produced SBA-labeled cells within islets. (c) Application of 1 x 10-8 M aldosterone stimulated SBAlabeled cells to form islets in combination with few tubules. Intense formation of SBA-labeled tubules was obtained by the use of (d) 1 x 10-7 M and (e) 1 x 10-6 M aldosterone. (f) Application of 1 x 10-5 M aldosterone did not further improve the development.