Male Reproductive Tract

Fluid Reabsorption by the Ductuli Efferentes Testis of the Rat Is Dependent on both Sodium and Chlorine

Abstract
The role of Na⁺ and Cl^- in fluid reabsorption by the efferent ducts was examined by perfusing individual ducts in vivo with preparations of 160 mM NaCl in which the ions were replaced, together or individually, with organic solutes whilst maintaining the osmolality at 300 mmol.kg ^-1. Progressively replacing NaCl with mannitol reduced net reabsorption of water and the ions in a concentration dependent manner, and caused net movement into the lumen at concentrations of NaCl less than at 80 mM. The net rates of flux were lower for Na⁺ than Cl^-. In collectates, [Na⁺] was greater than Cl^-], indicating that Cl^- transport is probably linked with another anion. Replacing either Na⁺ or Cl^- in perfusates (with choline and isethionate respectively) whilst maintaining the other inorganic ion at 160 mM also reduced net rates of reabsorption, in a concentration dependent manner, to zero when either ion was completely replaced. There were no significant differences in the osmolality of perfusate and collectate, and collectates contained a mean of 3.4 mM K⁺, indicating a back-flux of K⁺ into the lumen. It is concluded that fluid reabsorption from the efferent ducts is dependent on the transport of both Na⁺ and Cl^- from the lumen (from a luminal concentration of at least 70-80 mM), and that Cl^- transport is dependent on another anion. The epithelium is permeable to K⁺ and has a higher permeability to a range of organic solutes (mannitol, choline, isethionate) than epithelium in the proximal kidney tubules.

Key words: Male Reproductive Tract • Epididymis

This article has been cited by other articles:

				M. Kujala, S. Hihnala, J. Tienari, K. Kaunisto, J. Hastbacka, C. Holmberg, J. Kere, and P. Hoglund Expression of ion transport-associated proteins in human efferent and epididymal ducts Reproduction, April 1, 2007; 133(4): 775 - 784. [Abstract] [Full Text] [PDF]

				M. D. Alexandre, Q. Lu, and Y.-H. Chen Overexpression of claudin-7 decreases the paracellular Cl- conductance and increases the paracellular Na+ conductance in LLC-PK1 cells J. Cell Sci., June 15, 2005; 118(12): 2683 - 2693. [Abstract] [Full Text] [PDF]