Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2000-1-7
pubmed:abstractText
An increase in Na+/glucose cotransport upstream to the macula densa might contribute to the increase in single nephron GFR (SNGFR) in early diabetes mellitus by lowering the signal of the tubuloglomerular feedback, i.e., the luminal Na+, Cl-, and K+ concentration sensed by the macula densa. To examine this issue, micropuncture experiments were performed in nephrons with superficial glomeruli of streptozotocin-induced diabetes mellitus in rats. First, in nondiabetic control rats, ambient early distal tubular concentrations of Na+, Cl-, and K+ were about 21, 20, and 1.2 mM, respectively, suggesting collection sites relatively close to the macula densa. Second, glomerular hyperfiltration in diabetic rats was associated with a reduction in ambient early distal tubular concentrations of Na+, Cl-, and K+ by 20 to 28%, reflecting an increase in fractional reabsorption of these ions up to the early distal tubule. Third, in diabetic rats, early proximal tubular application of phlorizin, an inhibitor of Na+/glucose cotransport, elicited (1) a greater reduction in absolute and fractional reabsorption of Na+, Cl-, and K+ up to the early distal tubule, and (2) a greater increase in early distal tubular concentration of these ions, which was associated with a more pronounced reduction in SNGFR. These findings support the concept that stimulation of tubular Na+/glucose cotransport by reducing the tubuloglomerular feedback signal at the macula densa may contribute to glomerular hyperfiltration in diabetic rats. Glomerular hyperfiltration in diabetic rats serves to compensate for the rise in fractional tubular reabsorption to partly restore the electrolyte load to the distal nephron.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1046-6673
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2569-76
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Glomerular hyperfiltration in experimental diabetes mellitus: potential role of tubular reabsorption.
pubmed:affiliation
Department of Pharmacology, University of Tübingen, Germany. volker.vallon@uni-tuebingen.de
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't