Environmental Health Perspectives Volume 107, Number 8, August 1999
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Effects of Weight Loss and Exercise on the Distribution of Lead and Essential Trace Elements in Rats with Prior Lead Exposure
Shenggao Han, Wenjie Li, Uzma Jamil, Kyle Dargan, Michelle Orefice, Francis W. Kemp, and John D. Bogden
Department of Preventive Medicine and Community Health, UMDNJ--New Jersey Medical School, Newark, New Jersey, USA
Abstract
We studied the effects of weight loss and non-weight-bearing exercise (swimming) on blood and organ lead and essential metal concentrations in rats with prior lead exposure. Nine-week-old female Sprague-Dawley rats (n = 37) received lead acetate in their drinking water for 2 weeks, followed by a 4-day latency period without lead exposure. Rats were then randomly assigned to one of six treatment groups: weight maintenance with ad libitum feeding, moderate weight loss with 20% food restriction, and substantial weight loss with 40% food restriction, either with or without swimming. Blood lead concentrations were measured weekly. The rats were euthanized after a 4-week period of food restriction, and the brain, liver, kidneys, quadriceps muscle, lumbar spinal column bones, and femur were harvested for analysis for lead, calcium, copper, iron, magnesium, and zinc using atomic absorption spectrophotometry. Both swimming and nonswimming rats fed restricted diets had consistently higher blood lead concentrations than the ad libitum controls. Rats in the substantial weight loss group had higher organ lead concentrations than rats in the weight maintenance group. Rats in the moderate weight loss group had intermediate values. There were no significant differences in blood and organ lead concentrations between the swimming and nonswimming groups. Organ iron concentrations increased with weight loss, but those of the other metals studied did not. Weight loss also increased hematocrits and decreased bone density of the nonswimming rats. The response of lead stores to weight loss was similar to that of iron stores because both were conserved during food restriction in contrast to decreased stores of the other metals studied. It is possible that weight loss, especially rapid weight loss, could result in lead toxicity in people with a history of prior excessive lead exposure. Key words: exercise, food restriction, iron, lead, rat, swimming, weight loss. Environ Health Perspect 107:657-662 (1999). [Online 30 June 1999]
http://ehpnet1.niehs.nih.gov/docs/1999/107p657-662han/abstract.html
Address correspondence to J.D. Bogden, Department of Preventive Medicine and Community Health, UMDNJ--New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103-2714 USA. Telephone: (973) 972-5432. Fax: (973) 972-7625. E-mail: bogden@umdnj.edu
Presented in part at the Experimental Biology 98 meeting, San Francisco, California, 18-22 April 1998. The abstract was published in The FASEB Journal Part II 4905:A847 (1998).
This project was supported in part by NIH HL 56581.
Received 8 December 1998; accepted 5 April 1999.
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Last Updated: June 29, 1999