Question 1

What is the Meaning of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

Insulin-Like Growth Factor-1 (IGF-1) is a polypeptide hormone, structurally similar to insulin, primarily synthesized in the liver in response to growth hormone (GH) stimulation. This endocrine mediator facilitates many of GH's anabolic and growth-promoting effects, influencing cellular proliferation, differentiation, and tissue growth, regulating systemic growth and metabolism.

Question 2

What is the Context of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

IGF-1 functions as a central component of the somatotropic axis, a critical endocrine pathway regulating postnatal growth and metabolic homeostasis. This axis involves complex interplay between hypothalamic growth hormone-releasing hormone, pituitary growth hormone, and subsequent hepatic IGF-1 production. IGF-1 then exerts systemic effects and provides negative feedback.

Question 3

What is the Significance of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

Clinically, IGF-1 levels serve as a reliable indicator of average growth hormone secretion, essential for evaluating growth disorders and pituitary function. Abnormal concentrations can indicate growth hormone deficiency or excess, such as acromegaly. Monitoring IGF-1 assists clinicians in diagnosis and assessing treatment efficacy, directly impacting patient well-being.

Question 4

What is the Mechanism of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

IGF-1 exerts biological effects by binding to its transmembrane tyrosine kinase receptor on most cells. Ligand binding triggers receptor autophosphorylation, initiating intracellular signaling via PI3K/Akt and MAPK pathways. These pathways regulate protein synthesis, glucose uptake, cell survival, and division, contributing to tissue growth and repair.

Question 5

What is the Application of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

In clinical practice, serum IGF-1 levels are routinely used for diagnosing and monitoring growth hormone-related disorders. Low levels support deficiency diagnosis; elevated levels confirm acromegaly. Recombinant human IGF-1 is also a therapeutic agent, approved for severe primary IGF-1 deficiency, a rare condition of IGF-1 insufficiency.

Question 6

What is the Metric of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

The concentration of IGF-1 in blood serum is typically measured using immunoassays, providing a stable reflection of growth hormone secretion over time, unlike GH itself. Interpretation requires considering age- and sex-matched reference ranges, as levels naturally vary. Nutritional status, liver function, and other hormonal conditions influence measured IGF-1 concentrations.

Question 7

What is the Risk of Insulin-Like Growth Factor-1 (IGF-1)?

Accepted Answer

Both elevated and suppressed IGF-1 levels carry distinct clinical risks. Persistently high IGF-1, as in untreated acromegaly, can lead to cardiovascular disease, diabetes, and increased cancer risk. Conversely, sustained low IGF-1 levels, as in severe deficiency, can result in impaired growth and metabolic dysregulation. Therapeutic interventions require careful titration and monitoring.

Insulin-Like Growth Factor-1 (IGF-1)

Meaning

Context

Significance

Mechanism

Application

Metric

Risk

How Do Specific Macronutrient Ratios Affect Long-Term Hormone Production?