Abstract
Renal tubular excretion of choline by the organic cation transport pathway was demonstrated in vivo in the chicken using the Sperber technique and in the dog by renal artery infusion and measurement of the extraction into urine. In the chicken, choline transport was apparent only at infusion rates above 0.5 x 10-6 mol/kg/min. At infusion rates lower than this there was intrarenal metabolism of choline to betaine. Betaine was not actively transported in the chicken or the dog. In the chicken, a transport maximum for choline was attained when 2 x 10-6 mol/kg/min were reaching the infused kidney and the transport maximum was 1 x 10-6 mol/kg/min. The urine from the infused kidney contained choline and three renal metabolites of choline which were separated by electrophoresis and chromatography. Betaine and acetyLcholine have been identified and a large metabolic fraction remains unidentified. Ultrafiltration and ultracentrifugation studies revealed that neither choline nor betaine were bound to plasma proteins.
Footnotes
- Received December 30, 1971.
- Accepted March 6, 1972.
- © 1972, by The Williams & Wilkins Company
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|
