Renal transport of gossypol in the rabbit

Proc Soc Exp Biol Med. 1985 May;179(1):50-4. doi: 10.3181/00379727-179-42063.

Abstract

The present work was carried out to investigate the transport characteristics of gossypol, a toxic weak organic acid (pK = 7.2) contained in cottonseed, into the rabbit renal cortical slice. The uptake of gossypol increased linearly during a 2-hr incubation after which it leveled off with the average slice-to-medium concentration ratio (S/M) slightly above 20. In the presence of metabolic inhibitors, the S/M gossypol leveled off at about 9, suggesting an extensive binding of gossypol to tissue proteins. The uptake of gossypol was significantly inhibited by p-aminohippurate (PAH), probenecid, ouabain, and DIDS, all of which are known inhibitors of renal organic anion transport. However, the gossypol uptake was not affected by tetraethylammonium (TEA), a prototypical organic cation. Kinetic studies indicated that the apparent Km for gossypol transport is 0.28 mM, and also that probenecid inhibits gossypol transport in a competitive manner. It is concluded that gossypol is transported by the renal tubule through the classic organic anion system.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 2,4-Dinitrophenol
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / analogs & derivatives
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / pharmacology
  • Animals
  • Binding, Competitive
  • Biological Transport / drug effects
  • Biological Transport, Active / drug effects
  • Dinitrophenols / pharmacology
  • Gossypol / metabolism*
  • In Vitro Techniques
  • Iodoacetamide / pharmacology
  • Kidney Cortex / metabolism*
  • Kinetics
  • Nitrogen / pharmacology
  • Ouabain / pharmacology
  • Probenecid / pharmacology
  • Rabbits
  • Tetraethylammonium
  • Tetraethylammonium Compounds / pharmacology
  • p-Aminohippuric Acid / pharmacology

Substances

  • Dinitrophenols
  • Tetraethylammonium Compounds
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • Ouabain
  • Tetraethylammonium
  • Gossypol
  • Nitrogen
  • Probenecid
  • 2,4-Dinitrophenol
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
  • p-Aminohippuric Acid
  • Iodoacetamide