Investigation by luminal perfusion of the transfer of compounds into the epididymis of the anaesthetized rat.

Controlled perfusion through the lumen of the distal cauda epididymidis in the anaesthetized rat has been explored as a means of examining physiological exchanges from blood across the epididymal epithelium. The mean length of the perfused, sperm-free, tubule was 14.5 cm (+/- 1.5 s.e.m., n = 9). No cholesterol, protein or sialic acid was detected in the perfusate at flow rates exceeding 10 microliters/min, but at rates of 0.4--1.2 microliters/min, protein appeared at concentrations of 0.21--0.55 mg/ml (i.e. secretion rates of 0.21--0.83 micrograms/min; 3 rats). Glucose was detected at all perfusion rates (3--27 microliters/min) at concentrations of 0.06--0.58 mM (0.8--6.8% blood levels). During intravenous infusions of 3H2O, radioactivity in the perfusate rapidly attained 87% blood plasma concentrations; no radioactivity was detected when carboxy-E114C]dextran or methoxy-[3H]inulin were infused. Radioactivity appeared in the epididymal perfusate to 1--7% of blood levels during intravenous infusions of D-E1U-1RC]glucose or 3-O-methyl[1-3H]glucose. This evidence suggests that the preparation is physiological and could be used to explore the dynamics of exchanges between blood and epididymis.