Relations between enzyme activities connected with energy metabolism and parameters of food energy utilization in young and adult rats Part 2. Enzyme activities related to α-glycerophosphate shuttle in various tissues

✍ Scribed by Zahn, L. ;Noack, R. ;Steinbrecht, I. ;Wiswedel, I. ;Augustin, W.

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 569 KB
• Volume: 31
• Category: Article
• ISSN: 0027-769X
• DOI: 10.1002/food.19870310736

✦ Synopsis

The possible significance of food composition connected with the x-glycerophosphate (zGP) shuttle, a putative metabolic pathway of energy dissipation, was investigated at the level of enzyme activities. Liver, adipose tissue, slow-twitch and fast-twitch muscle of weaned male Wistar rats fed ad libitum for seven and for forty weeks a normal-protein (NP), a low-protein (LP), and a high-fat (HF) diet were examined. No striking dietary influences on cytosalic (NAD-linked glycerophosphate dehydrogenase. glyceraldehyde-phosphate dehydrogenase) and mitochondrial (succinate dehydrogenase. cytochronie c oxidase) enryme acticities could be detected. but mitochondrial a-glycerophosphate dehydrogenase (m-GPDH) showed an about twofold increase of its activity in the liver of LP-fed animals after seven weeks.

A relationship between the "gross efficiency of food energy utilization" and tissue m-GPDH levels could not be established in general. The proposed inducing effect of a LP diet on the magnitude of the G P shuttle obberved in the liver of young and adult rats seems to he interconnected reciprocally with the degree of~nctabolic energy dissipation only under the conditions of growth. The calculated capacities of the xGP shuttle are compatible with the assumption of its function as an energy dissipating pathway which is restricted in its magnitude ' Far( 1 Nahrung31([987) * 7 and 41 wk. represent Expt. I and I1 ** Calculated from activities [mU/g w.wt] *** Calculated from activities [mUjmg mitoch. prot.] **** Numeric values x lo-'