The long term goal of our research is to define the mechanisms by which the proximal tubule of the mammalian kidney transports sodium, bicarbonate, chloride and water and to characterize the manner by which they are physiologically regulated. To achieve this goal multiple techniques (free-flow micropuncture, in situ microperfusion, in vitro microperfusion, isolated membrane vesicles) are used and the data obtained by these various means are evaluated for internal consistency and integrated into a physiologically meaningful framework.
Specific aims are: 1) To further characterize the nature of the sodium-dependent and sodium-independent components of acidification. 2) To examine the role of adaptive changes in Na/H antiporter activity in modulating the rate of acidification. 3) To examine the role of sodium-dependent and sodium-independent mechanisms in the regulation of cell pH. 4) To determine the response of cell pH to changes in luminal and peritubular bicarbonate, Pco2 and pH. 5) To examine the role of cell pH in the regulation of the rate of acidification in response to changes in acid-base and potassium balance, and the administration of various agents such as glucocorticoids or parathormone. 6) To further characterize the luminal and basolateral mechanisms for transcellular Na and Cl transport. 7) To obtain more precise estimates of the transepithelial driving forces for water movement in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK027045-07
Application #
3228155
Study Section
General Medicine B Study Section (GMB)
Project Start
1980-06-01
Project End
1990-05-31
Budget Start
1986-06-01
Budget End
1987-05-31
Support Year
7
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Krapf, R; Pearce, D; Lynch, C et al. (1991) Expression of rat renal Na/H antiporter mRNA levels in response to respiratory and metabolic acidosis. J Clin Invest 87:747-51
Krapf, R (1989) Mechanisms of adaptation to chronic respiratory acidosis in the rabbit proximal tubule. J Clin Invest 83:890-6
Liu, F Y; Cogan, M G (1988) Atrial natriuretic factor does not inhibit basal or angiotensin II-stimulated proximal transport. Am J Physiol 255:F434-7
Liu, F Y; Cogan, M G (1988) Flow dependence of bicarbonate transport in the early (S1) proximal convoluted tubule. Am J Physiol 254:F851-5
Liu, F Y; Cogan, M G (1988) Angiotensin II stimulation of hydrogen ion secretion in the rat early proximal tubule. Modes of action, mechanism, and kinetics. J Clin Invest 82:601-7
Wong, K R; Xie, M H; Shi, L B et al. (1988) Urinary cGMP as biological marker of the renal activity of atrial natriuretic factor. Am J Physiol 255:F1220-4
Mitsuhashi, T; Ives, H E (1988) Intracellular Ca2+ requirement for activation of the Na+/H+ exchanger in vascular smooth muscle cells. J Biol Chem 263:8790-5
Wong, K R; Cogan, M G (1987) Comparison of the natriuresis and chloruresis associated with glomerular hyperfiltration induced by atrial natriuretic factor or glucagon. Life Sci 40:1595-600
Liu, F Y; Cogan, M G (1987) Angiotensin II: a potent regulator of acidification in the rat early proximal convoluted tubule. J Clin Invest 80:272-5

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