Abstract:
The effect of prolactin (PRL) onion transport across the porcine glandular endometrial epithelial cells was studied in primary cell culture using the short-circuit current technique. Addition of 1 μg/ml PRL either to the apical solution or to the basolateral solution produced a peak followed by a sustained increase in Isc, but with a lesser response when PRL was added apically. Basolateral addition of PRL increased the Isc in a concentration-dependent manner with a maximum effiect at 1 μg/ml and an effective concentration value of 120 ng/ml. The PRL-stimulated Isc was significantly reduced by pretreatment with an apical addition of 5-nitro-2-(3-phenylpropylamino) benzoic acid (200 μM), diphenylamine-2-carboxylic acid (1 mM) or 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (200 μM), Cl- channel blockers, but not by amiloride (10 μM), a Na+ channel blocker. In addition, pretreatment with bumetanide (200 μM), a Na + -K + -2Cl- cotransporter inhibitor, in the basolateral solution significantly reduced the PRL-stimulated Isc. Replacement of Cl- or HCO3- in the bathing solutions also decreased the Isc response to PRL. Pretreatment of the monolayer with AG490 (50 μM), an inhibitor of JAK2 activity significantly inhibited the PRL-induced increase in Isc. Western blot analysis of the porcine endometrial epithelial cells revealed the presence of short isoform of PRL receptor (PRLR-S) that could be regulated by 17β-estradiol. The results of this investigation showed that PRL acutely stimulated anion secretion across the porcine endometrial epithelial cells possibly through PRLR-S present in both apical and basolateral membranes. The PRL response appeared to be mediated by the JAK2-dependent pathway. © 2008 Society for Endocrinology.