Sustained strenuous exercise in sled dogs depresses three blood copper enzyme activities.

Studies show mixed conclusions about acute responses of copper status to strenuous exercise. Because copper function involves metalloenzyme activities, which might take days to change, the present study examined the response of three copper metalloenzyme activities to sustained strenuous exercise in sled dogs. A race lasting 12-15 d depressed activities for both plasma ceruloplasmin and erythrocyte superoxide dismutase in dogs consuming commercial dog foods and meats.

Oxidant stress in sled dogs subjected to repetitive endurance exercise.

Objective: To determine whether repetitive endurance exercise in sled dogs was associated with substantial lipid peroxidation, decreases in antioxidant capacity of the serum, and skeletal muscle damage.

Animals: 24 lightly trained sled dogs.

Procedure: 16 dogs completed a 58-km run on each of 3 consecutive days; the other 8 dogs (control) did not exercise during the study.

Short term citrus flavonoid supplementation of type II diabetic women: no effect on lipoprotein oxidation tendencies.

Flavonoids, which are dietary components and have possible drug uses, inhibit lipoprotein oxidation in vitro. The present study considered whether flavonoid supplementation in humans could influence lipoprotein vulnerability to oxidation. Citrus flavonoid supplementation (about 1g/day, 3 weeks), or placebo, was given to 40 Type II diabetic women, a population prone to oxidative stress.

Short-term zinc supplementation in women with non-insulin-dependent diabetes mellitus: effects on plasma 5'-nucleotidase activities, insulin-like growth factor I concentrations, and lipoprotein oxidation rates in vitro.

Non-insulin-dependent diabetes mellitus (NIDDM) may cause vulnerability to moderate zinc deficiency. In this study, short-term zinc supplementation (30 mg/d as amino acid chelate for 3 wk) elevated plasma zinc and activities of 5'-nucleotidase, a zinc-dependant enzyme, in 20 postmenopausal women with NIDDM. Placebo, given to 20 other women with NIDDM, had no effects on these indexes nor on any others taken in this study.

Moderate zinc deficiency in rats enhances lipoprotein oxidation in vitro.

Zinc inhibits low density lipoprotein oxidation in vitro. This observation and others provide indirect evidence that Zn affects radical-mediated processes. This study demonstrated that moderate Zn deficiency in rats produced very low and low density lipoproteins with abnormally high sensitivity to copper-catalyzed oxidation in vitro (short lag time, high propagation rate).