IGFBP-3
Also written as: IGFBP-3 — Insulin-like Growth Factor Binding Protein 3
Primary binding protein for IGF-1 in circulation, reflecting growth hormone status.
Full Definition
Insulin-like Growth Factor Binding Protein 3 (IGFBP-3) is the most abundant IGF binding protein in circulation and serves as the primary carrier protein for IGF-1. It is produced primarily by the liver under growth hormone control and forms a ternary complex with IGF-1 and an acid-labile subunit. IGFBP-3 levels correlate closely with growth hormone secretion and are often used alongside IGF-1 measurements to assess growth hormone status. Unlike IGF-1, IGFBP-3 levels are less affected by nutritional status, making it a valuable marker for growth hormone deficiency. Low levels suggest GH deficiency, while elevated levels may indicate GH excess or other endocrine disorders.
Usage
Usage note: Often measured with IGF-1; less affected by nutritional status than IGF-1.
In Context
- "Both IGF-1 and IGFBP-3 levels were below the 5th percentile, supporting the diagnosis of GH deficiency." — Laboratory interpretation note
- "IGFBP-3 remained low despite adequate nutrition, suggesting primary growth hormone insufficiency." — Endocrinology consultation