Removal of extracellular Mg2+ suppresses sulfation of glycoconjugates secreted from rabbit trachea in culture.
The influences of extracellular Ca2+ and Mg2+ concentrations on the basal secretion of glycoconjugates from rabbit trachea in organ culture were examined. Over 80% of the 35S-labeled and [3H]glucosamine-labeled glycoconjugates secreted by the trachea were digested upon incubation with chondroitinase ABC. The basal secretion did not occur in the medium at 4 degrees C, indicating an energy-dependent process. The basal secretion at 37 degrees C of 35S-labeled glycoconjugates was prominently suppressed in Mg(2+)-free Tyrode solution but not in Ca(2+)-free Tyrode solution containing ethyleneglycol bis(2-aminoethylether)tetraacetic acid (EGTA). In contrast, the basal secretion of [3H]glucosamine-labeled glycoconjugates was not affected by the Mg2+ concentration in the medium. The results suggest that extracellular Mg2+ largely contributes to sulfation of glycoconjugates basally secreted from rabbit trachea.
Kai
H
H
Department of Pharmacological Sciences, Faculty of Pharmaceutical Sciences, Kumamoto University, Japan.
Kimoto
A
A
Yoshitake
K
K
Matsumoto
S
S
Isohama
Y
Y
Takahama
K
K
Miyata
T
T
D000818:Animals; D002808:Chondroitin Lyases / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000378:metabolism; D004734:Energy Metabolism; D005944:Glucosamine / Q000378:metabolism; D005959:Glucosidases / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism*; D008274:Magnesium / Q000502:physiology*; D008297:Male; D009924:Organ Culture Techniques; D011817:Rabbits; D013431:Sulfates / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D013696:Temperature; D014132:Trachea / Q000166:cytology / Q000378:metabolism*
D013431:Sulfates; D013462:Sulfur Radioisotopes; D006003:Glycogen; D002809:Chondroitin Sulfates; D005959:Glucosidases; D002808:Chondroitin Lyases; D008274:Magnesium; D005944:Glucosamine