Abstract
The presence of lipoprotein lipase activity (LLA) in the adipose tissue of rats, rabbits and chickens is well established (1,2,3) but its presence in significant quantities in human adipose tissue has been questioned (4,5).
Angervall(4) found that lipoprotein lipase activity was considerably greater in chicken than in hen adipose tissue. Using a modification of the method described by Cherkes and Gordon(6), Chlouverakis(7) found that LLA in the adipose tissue of rats 4–5 weeks old was significantly greater than that of rats more than 5 months old. In interpreting this finding, however, it must be borne in mind that the protein/lipid ratio of young and old rat adipose tissue may differ(8).
This possibility was investigated by measuring the LLA in the adipose tissue of 2 groups of rats, one consisting of animals 4 to 6 weeks old and the other of much older animals (5 to 8 months), and expressing the results as LLA per unit of tissue wet weight and per unit of tissue protein. Other possible explanations for the apparent enzyme change associated with the ageing process, namely, a redistribution of the enzyme and its relationship to growth hormone, were also investigated.
Finally, in view of the conflicting reports regarding the enzyme activity in human adipose tissue, the LLA of subcutaneous fat was determined in material taken at biopsy.
Material and methods. Tissues. Male Wistar rats fed on a standard diet (Pillsbury's Thompson Diet Rat Cube, Birmingham, England), were used in all the experiments. “Young” rats were 4–6 weeks old and “old” rats were aged 5–8 months. Animals were killed by decapitation, adipose tissue was obtained from the epididymal fat body, muscle tissue from the diaphragm and the whole aorta down to its division to the iliac arteries.
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