Human Fallopian tubal epithelial cells in vitro:establishment of polarity and potential role of intracellular calcium and extracellular ATP in fluid secretion

A pure population of human Fallopian tubal epithelial cells has been isolated by enzyme digestion, grown in primary culture and used to explore the biochemical basis of oviduct fluid secretion. Confluence was achieved in 3–7 days. Immunocytochemical labelling for cytokeratins indicated that the cells were epithelial in nature and formed extensive desmosomal contacts, producinga polarized layer in culture. By growing the cells on collagen-impregnated filters, a small transepithelial electrical potential difference could be recorded, with the apical side of the cells negative with respect to the basal side. In addition, the consumption of glucose and the appearance of lactate were greater on the basal than on the apical side of the cells. Because intracellular Ca2+ ([Ca2+]1) is well established as a signal transduction agent in epithelial fluid secretion, the effect of a wide range of agonists on [Ca2+]1 in isolated tubal epithelial cells was studied using Fura-2. The only agent which induced a change in [Ca2+]1 was extracellular ATP. The transients induced were dependent on both intracellular and extracellular calcium. ATP added to the basal side of the cells of the polarized layer induced a transient increase in the potential difference. The data are consistent with a potential role for extracellular ATP in the regulation of human tubal fluid formation.