Amylin stimulates proximal tubular sodium transport and cell proliferation in the rat kidney

Peter J. Harris, Mark E. Cooper, Siriphun Hiranyachattada, Jennifer L. Berka, Darren J. Kelly, Michael Nobes, Peter J. Wookey

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Abstract

Tn autoradiopranhic. studies in anesthetized rats. 125I-labeled amylin binding was associated with proximal convoluted tubules but not distal tubules, interstitium, or glomeruli in the renal cortex. Split-drop micropuncture experiments showed that perfusion of the peritubular capillaries with amylin (10~9 M) stimulated proximal tubular fluid absorption by 28%. This effect was inhibited by luminal addition of ethylisopropylamiloride, indicating mediation by a brush-border Na /H4 exchanger. Intravenous infusion of an amylin binding antagonist, AC-187, reduced proximal fluid reabsorption (22%) in anesthetized rats, indicating a role for endogenous amylin in salt homeostasis. In primary cultures of rat proximal tubule cells, amylin (10-7 M) stimulated proliferation with a potency equal to epidermal growth factor. Peptide antagonists (AC-187, AC-413, and AC-512) of the amylin binding sites in the renal cortex blocked the mitogenic action of amylin. We conclude that amylin acts on renal proximal tubules to promote sodium and water reabsorption and cell proliferation. These novel actions may have implications for the development of hypertension for example in non-insulin-dependent diabetes mellitus and obesity in which hyperamylinemia has been observed.

Original languageEnglish
Pages (from-to)F13 - F21
Number of pages9
JournalAmerican Journal of Physiology
Volume272
Issue number1 PART 2
Publication statusPublished - 1997
Externally publishedYes

Keywords

  • Hyperplasia
  • Micropuncture
  • Proximal tubule

Cite this

Harris, P. J., Cooper, M. E., Hiranyachattada, S., Berka, J. L., Kelly, D. J., Nobes, M., & Wookey, P. J. (1997). Amylin stimulates proximal tubular sodium transport and cell proliferation in the rat kidney. American Journal of Physiology, 272(1 PART 2), F13 - F21.