title: Studies on the eye lens in poikilothermal animals. II. Stimulation of anaerobic glycolysis in rainbow trout lenses incubated with Ca2+-free medium.
abstract: The effects of Ca2+-free medium on cation levels and lactic acid production of rainbow trout lens incubated at various temperatures were examined in order to study passive cation transport system. Na+-K+ ratio (Na+/K+) increased when the lens was treated with Ca2+-free medium, but the effect of Ca2+-free medium was lowest between 15 and 20 degrees C which was the optimum water temperature for rainbow trout. Lactic acid production was stimulated between 15 and 20 degrees C in Ca2+-free medium. It was also stimulated at 37 degrees C in rat lenses incubated with Ca2+-free medium. However, the production was suppressed in ouabain-treated rainbow trout lenses. The suppression of Na+/K+ increase between 15 and 20 degrees C disappeared when the lens was treated with both Ca2+-free medium and ouabain. These results suggest that Na,K-ATPase activity and glycolysis were stimulated to prevent the increase of Na+/K+ in Ca2+-free medium. In addition, these results indicate that the optimum temperature was between 10 and 20 degrees C for the rainbow trout lens incubation in vitro, which is also the optimum water temperature in vivo.
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001831:Body Temperature; D002118:Calcium / Q000378:metabolism; D006019:Glycolysis; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism*; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012487:Salmonidae / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013696:Temperature; D014337:Trout / Q000378:metabolism*
chemical_list: D007773:Lactates; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D002118:Calcium