Leptin, the obesity gene protein product, is a hormone with multiple physiological functions in the human. However, there are few reports in the literature on its role in trace element metabolism in the normal population. Therefore, we investigated the association among serum leptin, zinc, copper, and zinc/copper ratio in 570 healthy men and women aged 15 yr and older. Serum leptin assay was done with a commercial enzymelinked immunosorbent assay kit; serum zinc and copper levels were measured by an atomic absorption spectrophotometer. Serum leptin was found to be positively associated with age (r=0.254, p<0.001), sex (r=0.406, p<0.001), body mass index (BMI) (r=0.553, p<0.001), and serum copper (r=0.419, p<0.001), but negatively associated with the zinc/copper ratio (r=-0.423, p<0.001). There was no significant association between serum leptin and zinc (r= -0.131, p>0.05). When the confounding effects of age, sex, and BMI were removed, serum leptin was still positively associated with serum copper (r=0.197, p=0.02) and the serum zinc/copper ratio (r=-0.182, p=0.03). These results suggest that copper and not zinc has an effect on serum leptin levels.

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We measured the activities of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPX) before therapy in 97 patients with cancer in various sites (gastrointestinal tract (GIT) (n=40), breast (n=30), and others (n=27)), and in 60 matched controls to assess antioxidant enzyme protection. Hemolysate hemoglobin (Hb) was measured spectrophotometrically. The activity of SOD (U/g Hb) was significantly lower in all sites (when all the cancer sites were considered as a group), GIT, breast, and other sites compared to the controls (P<0.0001, P<0.0001, P<0.0001 and P<0.0001, respectively). The activity of GPX (U/g Hb) was significantly decreased in all sites, GIT, and breast cancer sites than in the controls (P=0.024, P=0.033, and P=0.043, respectively). Age showed a weak negative correlation with enzyme activities in controls and patients. There was no significant association between SOD and GPX activities in either the controls or the patients. These results suggest that there may be a greater antioxidant burden for SOD than GPX in cancer, and that a weak association exists between the activities of the two enzymes in antioxidant protection.

Male Wistar rats fed with ferrocene had high hepatic iron loading (7.24 1.97 mg Fe/g tissue) after 6 weeks, principally located in lysosomes, which was comparable to the levels and distribution determined in human haemochromatosis.The two iron-storage proteins, ferritin and haemosiderin were isolated from the livers of the ferrocene-loaded rats and their iron cores were investigated by Mossbauer spectroscopy and inductively coupled plasma-emission spectrometry. Ferrihydrite was the predominant form of iron present in both ferritin and haemosiderin, while haemosiderin contained higher amounts of phosphorus, magnesium, calcium and barium, then either normal or ferrocene-loaded ferritin.Free-radical-mediated damage in the iron-loaded livers was inferred by the significant depletion of a-tocopherol in both the livers and subcellular hepatic lysosomal fraction, which inversely correlated with the inereasink iron ' content (r = -0.61 ; P < 0.05) and was associated with increased fragility of the lysosomal membranes.

Serum copper and zinc concentrations were measured in 560 apparently healthy Kuwaitis (238 males and 322 females) aged 15-80 years to assess micromineral effect on the indices of lipid metabolism. Following the recommended guidelines of the European Atherosclerosis Society (EAS) and the National Cholesterol Education Program Expert Panel (NCEPEP), the incidence of dyslipidemia was assessed from enzymatic assay data of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) concentrations. Males had significantly lower TC (P=0.029) and HDL-C (P<0.0001) levels than females, while TG were significantly (P=0.023) lower in females. The prevalence of hypercholesterolemia, hypertriglyceridemia, elevated LDL-C, and low HDL-C levels were 35, 30, 22, and 13%, respectively. Copper did not correlate with zinc (r = -0.067, P = 0.135) but was positively associated with TC (r=0.196, P<0.0001), LDL-C (r=0.134, P = 0.003), TG (r = 0.092, P=0.039), and age (r=0.281, P<0.0001). It is concluded that unlike in animal studies, copper excess in humans is associated with hyperlipidemia and therefore will predispose to atherosclerosis.