Home
Resources
Publications
Determination of Choline Dehydrogenase Activity Along the Rat Nephron

Determination of Choline Dehydrogenase Activity Along the Rat Nephron

B Miller, H Schmid, T J Chen, M Schmolke, W G Guder

Biol Chem Hoppe Seyler. 1996 Feb;377(2):129-37.

PMID: 8868068

Abstract:

A radioenzymatic microassay was developed to quantitate choline dehydrogenase activity in single microdissected nephron segments. This enzyme is the rate limiting step in the biosynthesis of betaine, which serves as an intracellular osmoregulatory organic solute in mammalian kidney. The enzyme localized in renal mitochondrial inner membrane forms betaine aldehyde, which in the assay is converted to betaine by oxidative treatment. A histochemical procedure based on the formazan detection of tetranitroblue tetrazolium chloride was applied in parallel. The results show that activities in proximal convoluted and straight tubules are more than 5 times higher (21 to 25 pmol h-1 mm tubule-1) compared to distal nephron segments with no significant differences along the proximal tubule. Along the osmotic gradient from the outer medullary towards the papillary structures enzyme activities increased in ascending limbs of Henle's loop and collecting tubules. Collecting ducts showed two times higher activities than ascending loop segments when corrected for tubular cell volumes. The quantitative data were confirmed by the histochemical procedure. The results allow for the conclusion that betaine synthesis is sufficient to build up renal betaine, but cannot explain the distribution pattern of betaine along the corticopapillary axis. Additional mechanisms like intrarenal and tubular transport have to be postulated.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP1184436	Tetranitroblue tetrazolium chloride		1184-43-6	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: