A vascularly perfused preparation of the Fallopian tube has been developed as a model to study the formation and composition of human tubal fluid. An artery serving the tube was cannulated and perfused at a rate of 0.7 ml/min for 1 h with Medium 199 supplemented with bovine serum albumin, heparin and antibiotics. A cannula was also inserted into the lumen. Light and scanning electron micrographs of control and perfused tubes showed that the epithelial lining was intact after perfusion. Tubal fluid was collected in 13 out of 19 experiments. Fluid could always be collected from patients who were in the follicular phase of their ovarian cycle. The mean rate of appearance was 48 microliters/h. The glucose, lactate and pyruvate concentrations in the tubal fluid, as assessed by fluorescence microanalysis, were 0.53, 8.58 and 0.17 mM respectively. There were no correlations between metabolite concentration and the length of perfusion, cannulation time, patient's age or condition. This technique provides a controlled method with which to access and examine human tubal fluid and will allow the physiology of both healthy and diseased tubes to be studied.

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, producing a 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+]i) is well established as a signal transduction agent in epithelial fluid secretion, the effect of a wide range of agonists on [Ca2+]i in isolated tubal epithelial cells was studied using Fura-2. The only agent which induced a change in [Ca2+]i 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.

The control of the formation of rabbit oviduct fluid and its relationship to the secretion of chloride ions has been studied using an in vitro vascularly perfused preparation. Fluid was produced at a rate of 43.41 microliters h-1 in oviducts from rabbits in oestrus. The rate was increased by isoprenaline and tetraethylammonium, decreased by dibutyryl cAMP, dihydro4,4'diisothiocyanatostilbene-2,2'-disulfonic acid (H2DIDS), and propranolol, while amiloride had no effect. H2DIDS induced a small decrease and isoprenaline a small increase in vascular to lumen Cl- flux but propranolol and dibutyryl cAMP had no effect. Oviducts from pseudopregnant animals treated with hCG three days before the experiment produced significantly less fluid than did those from rabbits in oestrus, but there was no difference in vascular to lumen Cl- flux. The concentration of K+ in oviduct fluid formed in vitro was more than three times higher than in the vascular perfusate. The ability of adrenergic agents to influence the formation of rabbit oviduct fluid could have clinical implications in the prevention or treatment of female infertility due to blockage of the Fallopian tubes and might also be useful in enhancing the secretory activity of oviduct cells maintained in co-culture with early embryos.

A pure population of rabbit oviduct epithelial cells was isolated and grown as a polarized monolayer on collagen-impregnated filters in primary culture. The cells were shown to be epithelial by immunocytochemical staining. The cells were mounted in a modified Ussing chamber which enabled ion transport across the cells to be studied. There was a net flux of Clin a basal to apical direction which was reversed by 1 mmol dibutyryl cyclic AMP l-1 (cAMP). A small but consistent transepithelial electrical potential difference (p.d.) of 0.86 mV was recorded with the apical side of the cells negative with respect to the basal. Adrenaline added to the basal side of the cells induced large transient increases in p.d. across the monolayer, involving both alpha and beta receptors. Adrenaline also induced a small increase in basal to apical Cltransport across the cells. It is proposed that adrenergic agonists and cAMP modulate rabbit oviduct fluid formation in part via an effect on transepithelial chloride transport.

Oviduct fluid is the medium in which fertilization and early embryonic development occur but little is known about the ionic basis of fluid secretion or its control. Since calcium ions (Ca2+) are involved in the mechanism of secretion in other epithelia, the intracellular calcium concentration ([Ca2+]i) was measured in single, rabbit oviduct epithelial cells in primary culture using the fluorescent dye Fura-2. The resting [Ca2+]i was constant (115 nM) in cells cultured for 2-7 days. Ion substitution experiments demonstrated the presence of a Na+/Ca(2+)-exchange system in the plasma membrane, whereas influx through channels was found to have only a minor role maintaining the resting [Ca2+]i. The addition of dibutyryl cAMP (db cAMP) induced two types of response: the first was an increase in [Ca2+]i, dependent on the presence of extracellular Ca2+, and the second was a zero response. Extracellular ATP induced a transient increase in [Ca2+]i owing to the release of Ca2+ from intracellular stores and Ca2+ entering the cell across the plasma membrane. It is proposed that these effects may be due to the presence of two types of cell in culture-the ciliated and non-ciliated (secretory type) oviduct epithelial cells.