An in vitro model based on cell monolayers grown on the underside of large- pore filters in bicameral chambers for studying thyrocyte-lymphocyte interactions

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.