[Effects of lanthanum ion on beta-endorphin biosynthesis and release in rat pituitary cells].
By using the primary culture method for pituitary cells in CSFM established in our laboratory, we studied the effects of lanthanum ion (La3+) on the biosynthesis and release of beta-endorphin-like immunoreactive substances in rat pituitary cells. Anterior and intermediate/posterior pituitary cells from male rats were cultured with arachidonic acid (AA), cortisol, dexamethasone (DEX) and lanthanum chloride. RIA was used to determine beta-EP levels in culture medium and within cells. The results indicated that AA could obviously stimulate the release of beta-EP from pituitary cells at a concentration of 2 x 10(-5) mol/L, while cortisol at 10(-6)mol/L and DEX at 10(-7)mol/L inhibited this release. These data coincide with results reported in the literature and thereby prove the reliability of the method used. When incubated with pituitary cells, lanthanum chloride induced a dose- and time-dependent release of beta-EP. Namely, beta-EP release continuously increased for a period under the action of La3+ of different doses (10(-5)mol/L and 10(-7)mol/L). beta-EP content in cells showed similar changes. These results suggest that beta-EP biosynthesis and release in rat anterior and intermediate/posterior pituitary cells are stimulated by lanthanum ions. They also provide experimental evidence for explaining the analgesic mechanism of lanthanum ions at the cellular level.
Institute of Radiation Medicine, CAMS and PUMC, Tianjin.
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D000818:Animals; D002478:Cells, Cultured; D007811:Lanthanum / Q000494:pharmacology*; D008297:Male; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D001615:beta-Endorphin / Q000096:biosynthesis*
D001615:beta-Endorphin; D007811:Lanthanum