Volume-sensitive taurine efflux from mammary tissue is not obliged to utilize volume-activated anion channels.
Cell-swelling, induced by a hyposmotic shock, activates the release of taurine from lactating rat mammary tissue explants. The degree of stimulation of taurine efflux was dependent upon the extent of cell-swelling. Volume-sensitive taurine release was attenuated by the anion transport inhibitors NPPB, DIOA, DIDS, niflumate, flufenamate, mefenamate and diiodosalicylate but not by salicylate. Cell-swelling, following a hyposmotic challenge, did not increase the unidirectional efflux of radiolabelled I- or D-asparate from mammary tissue explants. The results suggest that although mammary tissue expresses a volume-sensitive amino acid transport system which is inhibited by anion transport blockers the pathway has no identity with volume-activated anion channels.
Shennan
D B
DB
Hannah Research Institute, Ayr, Scotland, U.K.
Cliff
M J
MJ
Hawkins
P
P
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D048429:Cell Size; D005260:Female; D007473:Ion Channels / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism*; D009997:Osmotic Pressure; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000378:metabolism*
D007473:Ion Channels; D013654:Taurine; D001224:Aspartic Acid