Factors affecting the entry of testosterone into the lumen of the cauda epididymidis of the anaesthetized rat.
When [3H]testosterone was infused into the general circulation of the rat, perfusion of a length of the cauda epididymidis (17 +/- 1.0 (s.e.m.) cm, n = 36) with perfusates of varied composition revealed a low entry of radioactivity (1--10% plasma levels; 10 exps) with protein-free perfusates, and a greater entry (15--48%; 10 exps) when the perfusate contained bovine serum albumin (38 mg/ml). When the perfusate contained ovine or rat testicular fluid, or rat epididymal fluid at protein concentrations of 3 mg/ml or less, the entry of radioactivity into the epididymis was greater than when the perfusate contained 3 mg BSA/ml. The addition of ovine rete testis fluid protein (3 mg/ml to BSA (38 mg/ml) in the perfusate increased the uptake of radioactivity (58--106%; 6 exps). Radioactivity in blood was principally associated with testosterone (90, 95% total blood activity, 2 rats), whereas both [3H]testosterone (37, 41% total perfusate activity) and [3H]dihydrotestosterone (42, 63% total perfusate activity) was present in BSA-containing perfusates. The proportion of dihydrotestosterone appeared to increase when the perfusate contained protein of testicular origin.
D000818:Animals; D001826:Body Fluids / Q000502:physiology; D004822:Epididymis / Q000378:metabolism* / Q000502:physiology; D008297:Male; D010477:Perfusion; D051381:Rats; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013739:Testosterone / Q000097:blood / Q000378:metabolism*
D012710:Serum Albumin, Bovine; D013739:Testosterone