[Zinc and the growth hormone system]

Area of Science:

• Endocrinology
• Nutritional Science
• Growth Biology

Context:

• Chronic zinc deficiency is a known cause of impaired pondero-statural growth.
• The pituitary gland's role in growth appears less significant than liver-derived factors in this context.

Purpose:

• To investigate the mechanisms by which zinc deficiency affects physical growth.
• To elucidate the role of zinc in regulating growth hormone (GH) and insulin-like growth factor-I (IGF-I) synthesis and action.

Summary:

• Zinc deficiency significantly reduces liver synthesis of IGF-I and causes receptor resistance to both GH and IGF-I, leading to growth delay.
• Zinc supplementation increases IGF-I production and overcomes receptor resistance, restoring normal growth.
• Zinc's action extends to the receptor level, potentially by increasing receptor number.

Impact:

• This research clarifies zinc's critical role in mediating growth, particularly through IGF-I pathways.
• Findings suggest zinc supplementation as a therapeutic strategy for growth disorders linked to mineral deficiency.
• Understanding zinc's impact on receptor function provides new insights into endocrine regulation of growth.