Oxytocin and Vasopressin Stimulate Anion Secretion by Human and Porcine Vas Deferens Epithelia

Experiments were conducted to characterize the effects of oxytocin (OT) and vasopressin (VP) on epithelial cells isolated from human (1°HVD) and porcine (1°PVD) vas deferens and an immortalized epithelial cell line derived from porcine vas deferens (PVD9902 cells). Cultured monolayers were assessed in modified Ussing flux chambers and the OT- or VP-induced change in short circuit current (ISC) was recorded. All cell types responded to basolateral OT or VP with a transient increase in ISC that reached a peak of 3-5 μA cm⁻². Concentration-response curves constructed with 1°PVD and PVD9902 cells revealed that the apparent KD (kapp) for OT was ~100-fold less than the kapp for VP. Amplicons for the OT receptor (OXTR) and vasopressin type 2 and type 1a receptors (AVPR2 and AVPR1A) were generated with RT-PCR and the identification of each amplicon confirmed by sequence analysis. A selective antagonist for OXTR and AVPR1A fully blocked the effects of OT and partially blocked the effects of VP when assessed in both 1°PVD and PVD9902 monolayers. APVR2 antagonists blocked the effects of low (