Endogenous and exogenous citrate transport and release in prostatic preparations: semi-polarized two-dimensional cultures of human PNT2-C2 cells and isolated tubules and segments of rat prostate.
BACKGROUND
Electrophysiological characterization of normal human prostate epithelial cells showed exogenous trivalent citrate transport (release) to be K(+)-dependent.


METHODS
(1) Ussing chamber recordings of short circuit current (SCC) were used to study citrate transport in the same (PNT2-C2) cell line grown on micro-pore filters as a monolayer. (2) Release of endogenous citrate from confluent cultures and tubules and segments of rat prostate was measured using a fluorescence technique. (3) Enzyme-spectrophotometry was employed to detect citrate release from segments of rat prostate.


RESULTS
Citrate transport across the PNT2-C2 monolayer was asymmetrical, consistent with release into the lumen-side. Fluorescence and/or enzyme-spectrophotometric measurements showed that time-dependent citrate release (endogeneous and preabsorbed) occurred from rat prostate (tubules and segments), but not kidney or lung. The release was dependent on extracellular K(+) but not Na(+).


CONCLUSIONS
Citrate release from prostatic cells and tissues (rat and human) was K(+)-dependent, consistent with the previous electrophysiological data.
Mycielska
Maria E
ME
Department of Biological Sciences, Neuroscience Solutions to Cancer Research Group, Imperial College London, London SW7 2AZ, United Kingdom. m.mycielska@imperial.ac.uk
Krasowska
Monika
M
Grzywna
Zbigniew
Z
Djamgoz
Mustafa B A
MB
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001692:Biological Transport; D016764:Cell Polarity; D002478:Cells, Cultured; D019343:Citric Acid / Q000378:metabolism*; D006801:Humans; D008297:Male; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000494:pharmacology; D011467:Prostate / Q000378:metabolism*; D051381:Rats
D019343:Citric Acid; D001224:Aspartic Acid; D011188:Potassium