Zinc deficiency inhibits the direct growth effect of growth hormone on the tibia of hypophysectomized rats.
The effect of zinc deficiency on the direct-growth effect of growth hormone (GH) on tibia growth in hypophysectomized rats was studied. There were three dietary groups. Zinc deficient (ZD) group (0.9 mg/kg diet), control (C) group (66 mg/kg diet) and zinc adequate pair fed (PF) group (66 mg zinc/kg diet). All rats in each group received local infusion of recombinant human-growth hormone (hGH) (1 microgram/d), except for half of the animals in the control group, which were sham-treated, receiving vehicle infusion only. The substances were infused continuously for 13 d by osmotic minipumps through a catheter implanted into the right femoral artery. Food intake was lower and body weight loss was greater in ZD, and PF animals compared with C animals (p < 0.001). Tissue-zinc concentration and plasma alkaline-phosphatase activity were decreased (p < 0.05) by dietary-zinc deficiency. GH infusion increased the tibial-epiphyseal width of the treated right limb, but not of the noninfused left limb in C and PF animals. However, in ZD rats, no difference was found between the infused and the noninfused limbs. These results demonstrate that zinc deficiency inhibits the direct-growth effect of GH on long-bone growth.
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School of Dietetics and Human Nutrition, McGill University, Ste. Anne de Bellevue, Quebec, Canada.
Rojhani
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A
D000818:Animals; D003677:Deficiency Diseases / Q000503:physiopathology; D013006:Growth Hormone / Q000037:antagonists & inhibitors* / Q000097:blood; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000254:growth & development*; D015032:Zinc / Q000008:administration & dosage / Q000097:blood / Q000172:deficiency*
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D015032:Zinc