Human serum alpha 2HS-glycoprotein modulates in vitro bone resorption.
We previously isolated a family of bone-resorbing proteins from human cancer ascites fluid and established that the three purified bone-resorbing proteins were chemically and immunochemically related to each other and to alpha-2HS glycoprotein (alpha 2HS). After this finding we purified the normal human serum counterpart of these ascites proteins and studied its effects on bone resorption. The bone-resorbing properties of normal human serum alpha 2HS were examined in vitro over a wide dose range. This normal human serum glycoprotein had a biphasic effect on 45Ca2+ release from bone. More specifically, this protein stimulated bone resorption at the lower concentrations tested, with a maximum effect [treated over control ratio of 2.5 +/- 0.30 (+/- SE); P less than 0.01] at 40 micrograms/mL. In contrast, at doses above 40 micrograms/mL, a sharp decline in calcium mobilization occurred, with a return to baseline occurring above 80 micrograms/mL. These results suggest that serum alpha 2HS may participate in the regulation of bone metabolism in vivo.
Colclasure
G C
GC
Department of Biochemistry, Boston University School of Medicine, Massachusettes 02118.
Lloyd
W S
WS
Lamkin
M
M
Gonnerman
W
W
Troxler
R F
RF
Offner
G D
GD
Bürgi
W
W
Schmid
K
K
Nimberg
R B
RB
D000328:Adult; D000596:Amino Acids / Q000032:analysis; D001202:Ascitic Fluid / Q000032:analysis; D001798:Blood Proteins / Q000032:analysis / Q000494:pharmacology*; D001862:Bone Resorption / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002132:Calcium Radioisotopes; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000032:analysis; D060749:alpha-2-HS-Glycoprotein
C556354:AHSG protein, human; D000596:Amino Acids; D001798:Blood Proteins; D002132:Calcium Radioisotopes; D060749:alpha-2-HS-Glycoprotein; D002118:Calcium