Growth hormone: Synthesis and regulation

Area of Science:

• Endocrinology and Metabolism
• Molecular Biology
• Physiology

Background:

• Growth hormone (GH) is crucial for postnatal growth and metabolic regulation.
• GH acts through direct, paracrine, autocrine, and GH-IGF-1 axis-mediated mechanisms.
• Understanding GH signaling is vital for comprehending its multifaceted roles in the body.

Purpose of the Study:

• To review the molecular and physiological basis of GH secretion and action.
• To examine factors modulating GH, including central/peripheral signals and metabolic states.
• To explore GH receptor signaling, intracellular pathways, and hormone resistance mechanisms.

Main Methods:

• Comprehensive literature review of GH secretion and action.
• Analysis of regulatory mechanisms involving the hypothalamic-pituitary system.
• Discussion of factors influencing GH physiological variability and pathological implications.

Main Results:

• GH secretion is pulsatile and tightly regulated by hypothalamic hormones (GHRH, somatostatin, ghrelin) and feedback loops (GH, IGF-1).
• Physiological variables like sleep, nutrition, stress, age, and sex significantly impact GH levels.
• GH resistance mechanisms and the somatotropic axis's role in conditions like GH deficiency and acromegaly are detailed.

Conclusions:

• GH action is complex, involving intricate signaling networks and influenced by numerous factors.
• Dysregulation of the somatotropic axis has significant clinical implications.
• This review provides a foundational understanding of GH's role in health and disease.