Received October 2, 2006
Accepted on May 31, 2007

BASIC RESEARCH

Origin and Fate of Pendrin-Positive Intercalated Cells in Developing Mouse Kidney

Hyun-Kuk Song ^*, Wan-Young Kim ^*, Hyun-Wook Lee ^*, Eun-Young Park ^*, Ki-Hwan Han , Soren Nielsen , Kirsten M. Madsen , and Jin Kim ^*1

*Department of Anatomy and Cell Death Disease Research Center, The Catholic University of Korea, and Department of Anatomy, Ewha Womans University, Seoul, Korea; Water and Salt Research Center, University of Aarhus, Aarhus, Denmark; and Department of Medicine, University of Florida, Gainesville, Florida

¹ To whom correspondence should be addressed. E-mail: jinkim{at}catholic.ac.kr.

	Abstract

Pendrin is an apical anion exchanger found in type B and nonA-nonB intercalated cells that is involved in bicarbonate secretion. The purpose of this study was to establish the origin and fate of pendrin-positive intercalated cells in the mouse kidney. Using immunohistochemistry, we found that pendrin-positive cells first appeared in the connecting tubule at embryonic day 14 (E14) and subsequently in the medullary collecting duct at E18. Most of the pendrin-positive cells in the connecting tubule were nonA–nonB intercalated cells, wheras those in the medullary collecting duct were type B intercalated cells. In the cortical collecting duct, pendrin-positive cells appeared in the inner part at day 4 after birth and in the outer part at day 7. Pendrin-positive cells gradually disappeared by apoptosis from the inner part of the medullary collecting duct two weeks after birth. Using 5-bromo-2'deoxy-uridine (BrdU) to follow cell proliferation, we determined that selective proliferation of pendrin-positive intercalated cells does not occur; instead, these cells may arise from undifferentiated precursor cells from separate foci, one in the connecting tubule and one in the collecting duct.