Alterations in bone forming cells due to reduced weight bearing.
A reduction in new bone formation occurred as a result of space flight (Cosmos 1129) and in the suspended animal model of Morey-Holton.  Our results indicate that alkaline phosphatase activity of the bone forming cells is also reduced under these conditions, and the cells in the diaphysis are more affected than those in the metaphyseal region.  In addition, these cells show (1) reduced proline incorporation into bone matrix, and (2) increased intracellular lysosomal activity.  A change in the cytoskeleton could be the common factor in explaining these results.  This suggestion is further supported by our previous observations that colchicine injections result in decreased osteoblastic function.
Doty
S B
SB
Columbia University, New York 10032, USA.
Morey-Holton
E
E
D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D001846:Bone Development / Q000502:physiology; D003094:Collagen / Q000096:biosynthesis*; D018483:Diaphyses; D005269:Femur; D006614:Hindlimb; D006909:Hydroxyproline / Q000378:metabolism; D007103:Immobilization / Q000009:adverse effects*; D008297:Male; D010006:Osteoblasts / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D013977:Tibia
D003094:Collagen; D000469:Alkaline Phosphatase; D006909:Hydroxyproline