Two preparations for the study of the isolated rabbit oviduct.

When rabbit oviducts were slit open along their length, cut into small pieces, and incubated in Krebs--Ringer--bicarbonate medium, the tissue slices took up O2 at a steady rate for 40 min, retained approximately 70% of their adenine nucleotides, and were suitable for metabolic studies of the oviduct. In a second preparation, oxygenated Krebs--Ringer--bicarbonate medium was recirculated at 700 microliters/min through the lumen of the whole oviduct, severed of its blood supply, while the serosal surface was bathed in a similar medium. The preparation took up O2, maintained a steady potential difference across its mucosal and serosal surfaces, and transported 2-deoxy D-glucose selectively for at least 40 min. In oviducts taken from rabbits injected 3 days previously with hCG, there was greater than 4-fold increase in the initial transmural potential difference.

The movement of amino acids into rabbit oviductal fluid.

Twenty-three amino acids appeared linearly in oviduct fluid to reach an average concentration 27% of that in the plasma, with glycine and alanine present in greatest amount. In contrast, the concentration of urea in the fluid approached its plasma concentration after 1 h, and remained at this level for the duration of the experiment. The oviduct was unable to bring the overall uphill transport of amino acids from plasma to oviduct lumen. The amounts of amino acids appearing in the oviduct lumen of rabbits injected 3 days previously with hCG were mostly similar to those of the controls, but the movements of 6 neutral amino acids appeared to be enhanced relative to their plasma concentrations following ovulation.

Evidence for the facilitated diffusion of glucose into rabbit oviductal fluid.

Glucose movement into the oviductal fluid of rabbits was studied in anaesthetized animals. The oviducts were cannulated at each end, and 2 ml 0-9% NaCl at 37 degrees C were recirculated through the lumen for 4 h. D-Glucose appeared linearly in the fluid, reaching an average concentration of 2-6 mM. The rate of D-glucose appearance was 17 times greater than that of L-glucose, infused intravenously, suggesting that a component of the D-glucose movement operated by facilitated diffusion. The oviduct was unable to move glucose against an adverse plasma to lumen concentration gradient. We suggest that the glucose entering the oviductal fluid originates in the plasma and that the mucosal portion of the oviduct is responsible for this sugar transfer.