Permeability characteristics of the epithelium in the rat caput epididymidis.
Micropuncture techniques were used to study the in-vivo transfer of radioactive compounds of different molecular weights across the epithelium of the rat caput epididymidis. Small molecular weight compounds such as 3H2O and [14C]urea equilibrated in less than 20 min and 2 h respectively after intravenous injection. Compounds of larger molecular weight ([3H]polyethylene glycol, [3H]inulin and 125I-labelled bovine serum albumin) entered the lumen more slowly and reached less than 5% of blood plasma concentrations 3 h after injection. The luminal concentration of [3H]inulin remained below 7% of the blood level for 18 h. These results demonstrate that a permeability barrier exists in the epithelium of the rat caput epididymidis.
D000818:Animals; D002463:Cell Membrane Permeability; D004822:Epididymis / Q000378:metabolism*; D007444:Inulin / Q000378:metabolism; D008297:Male; D011092:Polyethylene Glycols / Q000378:metabolism; D051381:Rats; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014508:Urea / Q000378:metabolism; D014867:Water / Q000378:metabolism
D014867:Water; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D014508:Urea; D007444:Inulin