Abstract

The control of acid-base regulation by the kidney is critical in maintaining body electrolyte homeostasis. The inner medullary collecting duct (IMCD) has been shown to be an important nephron site where a significant amount of acid found in the urine is secreted and where the steepest pH gradients are found. The purpose of these studies is to clarify the mechanisms and modulators of acid secretion along the IMCD. In this proposed research we will utilize the complementary techniques of in vivo IMCD microcatheterization and in vitro IMCD cell culture and morphologic analysis to explore the effect of acidification adaptation, renal insufficiency, aldosterone and potassium on IMCD acidification. We will explore the likelihood that there are 2 distinct cell types along the IMCD which have different acid secreting characteristics. We will determine the presence and quantitative importance of the proton pump, the Na+/H+, the HCO3-/C1 and Na+-HCO3- transporters on cell pH regulation. These studies will provide significant new information regarding IMCD acidification.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK028164-14
Application #
3228636
Study Section
General Medicine B Study Section (GMB)
Project Start
1988-09-01
Project End
1991-08-31
Budget Start
1989-09-01
Budget End
1990-08-31
Support Year
14
Fiscal Year
1989
Total Cost
Indirect Cost

  Institution

Name
Boston University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118

  Publications

Banerjee, A; Li, G; Alexander, E A et al. (2001) Role of SNAP-23 in trafficking of H+-ATPase in cultured inner medullary collecting duct cells. Am J Physiol Cell Physiol 280:C775-81
Alexander, E A; Brown, D; Shih, T et al. (1999) Effect of acidification on the location of H+-ATPase in cultured inner medullary collecting duct cells. Am J Physiol 276:C758-63
Banerjee, A; Shih, T; Alexander, E A et al. (1999) SNARE proteins regulate H(+)-ATPase redistribution to the apical membrane in rat renal inner medullary collecting duct cells. J Biol Chem 274:26518-22
Obrador, G; Yuan, H; Shih, T M et al. (1998) Characterization of anion exchangers in an inner medullary collecting duct cell line. J Am Soc Nephrol 9:746-54
Alexander, E A; Shih, T; Schwartz, J H (1997) H+ secretion is inhibited by clostridial toxins in an inner medullary collecting duct cell line. Am J Physiol 273:F1054-7
Schwartz, J H (1995) Renal acid-base transport: the regulatory role of the inner medullary collecting duct. Kidney Int 47:333-41
Schwartz, J H; Masino, S A; Nichols, R D et al. (1994) Intracellular modulation of acid secretion in rat inner medullary collecting duct cells. Am J Physiol 266:F94-101
Schwartz, G J; Brown, D; Mankus, R et al. (1994) Low pH enhances expression of carbonic anhydrase II by cultured rat inner medullary collecting duct cells. Am J Physiol 266:C508-14
Slotki, I; Schwartz, J H; Alexander, E A (1993) Interrelationship between cell pH and cell calcium in rat inner medullary collecting duct cells. Am J Physiol 265:C432-8
Mankus, R; Schwartz, J H; Alexander, E A (1993) Acidification adaptation in cultured inner medullary collecting duct cells. Am J Physiol 264:F765-9

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