Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-19957
Busque, S M; Wagner, C A (2009). Potassium restriction, high protein intake, and metabolic acidosis increase expression of the glutamine transporter SNAT3 (Slc38a3) in mouse kidney. American Journal of Physiology. Renal Physiology, 297(2):F440-F450.
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Kidneys produce ammonium to buffer and excrete acids through metabolism of glutamine. Expression of the glutamine transporter Slc38a3 (SNAT3) increases in kidney during metabolic acidosis (MA), suggesting a role during ammoniagenesis. Potassium depletion and high dietary protein intake are known to elevate renal ammonium excretion. In this study, we examined SNAT3, phosphate-dependent glutaminase (PDG), and phosphoenolpyruvate carboxykinase (PEPCK) regulation during a control (0.36%) or low-K(+) (0.02%) diet for 7 or 14 days or a control (20%) or high-protein (50%) diet for 7 days. MA was induced in control and low-K(+) groups by addition of NH(4)Cl. Urinary ammonium excretion increased during MA, after 14-day K(+) restriction alone, and during high protein intake. SNAT3, PDG, and PEPCK mRNA abundance were elevated during MA and after 14-day K(+) restriction but not during high protein intake. SNAT3 protein abundance was enhanced during MA (both control and low K(+)), after 14-day low-K(+) treatment alone, and during high protein intake. Seven-day dietary K(+) depletion alone had no effect. Immunohistochemistry showed SNAT3 staining in earlier parts of the proximal tubule during 14-day K(+) restriction with and without NH(4)Cl treatment and during high protein intake. In summary, SNAT3, PDG, and PEPCK mRNA expression were congruent with urinary ammonium excretion during MA. Chronic dietary K(+) restriction, high protein intake, and MA enhance ammoniagenesis, an effect that may involve enhanced SNAT3 mRNA and protein expression. Our data suggest that SNAT3 plays an important role as the glutamine uptake mechanism in ammoniagenesis under these conditions.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Center for Integrative Human Physiology|
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
|DDC:||570 Life sciences; biology|
610 Medicine & health
|Deposited On:||29 Jul 2009 12:02|
|Last Modified:||28 Nov 2013 01:36|
|Publisher:||American Physiological Society|
|Citations:||Web of Science®. Times Cited: 14|
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