The Journal of nutrition
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The Journal of nutrition · Apr 1995
The impaired growth induced by zinc deficiency in rats is associated with decreased expression of the hepatic insulin-like growth factor I and growth hormone receptor genes.
This study was conducted to determine whether dietary zinc status affects the expression of the insulin-like growth factor I and growth hormone receptor/growth hormone binding protein genes in the liver of growing rats. Weanling male Sprague-Dawley rats were randomly allotted to zinc-deficient, pair-fed or ad libitum-fed dietary treatments and fed diets containing no added zinc for 14 d. Zinc acetate was added to the deionized, distilled water (30 mg/L) provided to pair-fed and ad libitum-fed rats. ⋯ In contrast, the abundance of the 1.8-kb insulin-like growth factor I transcript was unaffected by zinc deficiency. The growth hormone receptor mRNA levels of zinc-deficient and pair-fed rats were 17 and 50% and their growth hormone binding protein mRNA levels were 46 and 65% those of the ad libitum-fed rats. In summary, zinc deficiency markedly decreases expression of the insulin-like growth factor I and growth hormone receptor genes.(ABSTRACT TRUNCATED AT 250 WORDS)
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The Journal of nutrition · Apr 1995
Randomized Controlled Trial Comparative Study Clinical TrialAge differences in the impact of nutritional supplementation on growth.
Supplementary feeding programs are common in developing countries. These programs often cannot demonstrate an impact on child growth, however, possibly because they tend to reach older children. This study examines the impact of nutritional supplementation on annual growth rates in length and weight from birth to 7 y of age in 1208 rural Guatemalan children. ⋯ There was no impact of nutritional supplementation on growth between 3 and 7 y of age. Patterns were the same if supplement intakes were expressed as a percent of recommended allowances or growth was expressed as a percent of the expected rate. These impacts of nutritional supplementation on growth coincide with the ages when growth velocities, as well as growth deficits, are greatest in this population.