. Calcified tissues; proceedings. Bone; Collagen; Calcification. 14 W. A. DE VOOGD VAN DER StRAATEN. lactate-^'^^pyruvate " flavoprot red ftavoprot c oxalo^acetate citrate NADH aconitase 'r^oj^'^^o ,50 citrate fumarate \^nadp / C Deh. X lytic pathway, the pentose phosphate cycle and the Krebs cycle are operative. 2. However concerning the oxidative phosphorylation nearly nothing is known. 3. The activities of the pentose shunt dehydrogenases are suprisingly high in dia- physeal rabbit bone tissue as com- glucose /^ gtuco5e-6-P<~ poiysaccha- pared with kidney, liver and brain tissu
. Calcified tissues; proceedings. Bone; Collagen; Calcification. 14 W. A. DE VOOGD VAN DER StRAATEN. lactate-^'^^pyruvate " flavoprot red ftavoprot c oxalo^acetate citrate NADH aconitase 'r^oj^'^^o ,50 citrate fumarate \^nadp / C Deh. X lytic pathway, the pentose phosphate cycle and the Krebs cycle are operative. 2. However concerning the oxidative phosphorylation nearly nothing is known. 3. The activities of the pentose shunt dehydrogenases are suprisingly high in dia- physeal rabbit bone tissue as com- glucose /^ gtuco5e-6-P<~ poiysaccha- pared with kidney, liver and brain tissue. Moreover the strik- ingly high relative activity of pyri- dine nucleotide transhydrogenase — being as it is, involved in the reoxydation of NADPH — seems to underline the importance of the NADP dependent dehydrogenases in bone. 4. On the other hand the relatively low activity of Succinic Cytochrome C reductase suggests a less important role of the tri- carboxylic acid cycle. 5. Concern- ing the citrate metabolism, espe- cially under the influence of PTH, the problem about the balance be- tween citrate synthesis and oxida- tion is still open to some contro- versy. 6. Finally, in this picture we meet already some connections between carbohydrate metabolism and protein synthesis, especially collagen synthesis. These connec- tions concern carbohydrate iner- mediates being precursors of some amino acids and furthermore the ribose synthesis being prerequisite to RNA synthesis and so indirectly to protein synthesis; see Fig. 1. Now although the data concerning the action of PTFi on bone tissue belong to a subgroup of our universe of discourse, they are of direct relevance, because they reveal in all probability the key points of bone metabolism. Moreover, though not being essential, work on the main pathways is mainly done by students in the PTE field. And so an essential contribution to our picture is Hekkelman's hypothesis stating that PTE induces a decrease of the amount of
Size: 1515px × 1649px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookcollectionbiodiversity, booksubjectbone
