This project deals with the mechanisms that allow cells to keep their water content at a constant level. It focuses on the receptors that perceive changes in cell water, the membrane transporters that correct perturbations in cell water, and the signaling systems that link the receptors with the transporters.
The aims of the project are to identify the receptor(s), to study how volume-activated transport systems are coordinated, and to study how volume is regulated in vivo. Red cells are selected for study because of their anatomical simplicity. The experiments involve measurements of water, ions, and metabolic intermediates in red cells plus radioisotopic labeling and separation of red cell membrane proteins. The in vivo work entails the administration of an antimetabolite, hydroxyurea, to experimental animals. The red cells of human subjects who are being treated with hydroxyurea for myeloproliferative disorders will also be studied. The clinical importance of this work is that changes in cell water content are a common and potentially lethal manifestation of many disease states, including brain injury, sickle cell disease, and acute renal failure.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK011356-26
Application #
3224785
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1975-09-01
Project End
1995-08-31
Budget Start
1992-09-01
Budget End
1993-08-31
Support Year
26
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Colclasure, G C; Parker, J C; Dunham, P B (1995) Creatine kinase is required for swelling-activated K-Cl cotransport in dog red blood cells. Am J Physiol 268:C660-8
Parker, J C; Dunham, P B; Minton, A P (1995) Effects of ionic strength on the regulation of Na/H exchange and K-Cl cotransport in dog red blood cells. J Gen Physiol 105:677-99
Colclasure, G C; Parker, J C (1993) ATP dependence of K-Cl cotransport in dog red blood cells. Am J Physiol 265:C1648-52
Parker, J C (1993) Urea alters set point volume for K-Cl cotransport, Na-H exchange, and Ca-Na exchange in dog red blood cells. Am J Physiol 265:C447-52
Parker, J C (1992) Volume-activated cation transport in dog red cells: detection and transduction of the volume stimulus. Comp Biochem Physiol Comp Physiol 102:615-8
Orringer, E P; Parker, J C (1992) Hydroxyurea and sickle cell disease. Hematol Pathol 6:171-8
Parker, J C; Colclasure, G C (1992) Actions of thiocyanate and N-phenylmaleimide on volume-responsive Na and K transport in dog red cells. Am J Physiol 262:C418-21
Colclasure, G C; Parker, J C (1992) Cytosolic protein concentration is the primary volume signal for swelling-induced [K-Cl] cotransport in dog red cells. J Gen Physiol 100:1-10
Parker, J C; Colclasure, G C (1992) Macromolecular crowding and volume perception in dog red cells. Mol Cell Biochem 114:9-11
Orringer, E P; Blythe, D S; Johnson, A E et al. (1991) Effects of hydroxyurea on hemoglobin F and water content in the red blood cells of dogs and of patients with sickle cell anemia. Blood 78:212-6

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