View Single Post
  #1  
Unread 08-22-2010, 03:41 AM
nmrlearner's Avatar
nmrlearner nmrlearner is offline
Senior Member
 
Join Date: Jan 2005
Posts: 23,137
Points: 193,617, Level: 100
Points: 193,617, Level: 100 Points: 193,617, Level: 100 Points: 193,617, Level: 100
Level up: 0%, 0 Points needed
Level up: 0% Level up: 0% Level up: 0%
Activity: 50.7%
Activity: 50.7% Activity: 50.7% Activity: 50.7%
Last Achievements
Award-Showcase
NMR Credits: 0
NMR Points: 0
Downloads: 0
Uploads: 0
Default An NMR study of cellular phosphates and membrane transport in renal proximal tubules.

An NMR study of cellular phosphates and membrane transport in renal proximal tubules.

Related Articles An NMR study of cellular phosphates and membrane transport in renal proximal tubules.

Am J Physiol. 1995 Mar;268(3 Pt 2):F375-84

Authors: Chobanian MC, Anderson ME, Brazy PC

Technical limitations in the measurement of cellular phosphates have hindered studies of interrelationships between cellular Pi, its transport, and its metabolism in renal proximal tubule (PT) cells. We have developed a noninvasive 31P-nuclear magnetic resonance (NMR) probe-perifusion system to measure cellular Pi and have utilized this system to investigate relationships in canine PT cells between the membrane transport and the cellular content of Pi. With 1.2 mM Pi in the extracellular medium, the cellular Pi content of PT averaged 4.94 +/- 0.55 nmol/mg protein. Inhibition of Pi uptake by removal of extracellular Pi rapidly decreased all cellular phosphate compounds to values that were between 55 and 85% of control. Partial replacement of extracellular Pi (0.4 mM) increased cellular phosphates up to 84-100% of control values. Inhibition of Na(+)-K(+)-adenosinetriphosphatase uptake by the addition of ouabain failed to change either cellular Pi or organic phosphates. Reducing the basolateral membrane potential with the addition of barium chloride increased cellular Pi content by nearly 30%. Maximal contents of cellular Pi and ATP were achieved at 0.4 mM Pi in the presence of an inwardly directed Na+ gradient and at 0.8 mM Pi in its absence. These data indicate that cellular Pi content in canine PT is regulated by Na(+)-dependent and -independent transport mechanisms and by the membrane potential across the basolateral membrane. Lastly, cellular ATP content was found to be directly proportional to the cellular Pi content over a physiological range.

PMID: 7900836 [PubMed - indexed for MEDLINE]



Source: PubMed
Reply With Quote


Did you find this post helpful? Yes | No