Bone metabolism in relation to alterations in systemic growth hormone

Area of Science:

• Endocrinology
• Bone Biology
• Skeletal Homeostasis

Background:

• Growth hormone (GH) and insulin-like growth factors (IGFs) regulate adult bone mass through complex interactions.
• In vitro studies elucidated molecular pathways, but systemic effects in vivo require further investigation.
• Genetically modified mouse models have been pivotal in understanding IGFs' role in skeletal homeostasis.

Purpose of the Study:

• To review recent findings on GH/IGF effects on adult bone remodeling.
• To emphasize data from patient populations (acromegaly, GH deficiency, osteoporosis) and experimental models.
• To discuss the role of IGF-I in coupling bone resorption and formation via OPG and RANKL.

Main Methods:

• Analysis of data from patient populations with altered GH/IGF levels.
• Examination of experimental models with genetically modified GH and IGF family members.
• Review of in vitro and in vivo studies on GH and IGF signaling in bone cells.

Main Results:

• Systemic IGF-I plays a critical role in the development and maintenance of the adult skeleton.
• GH and IGFs influence bone remodeling through autocrine, paracrine, and endocrine mechanisms.
• IGF-I acts as a coupling agent in bone remodeling by modulating OPG and RANKL.

Conclusions:

• GH and IGFs are essential regulators of adult bone remodeling and skeletal homeostasis.
• Understanding the systemic and local actions of GH/IGFs is crucial for bone health.
• Further research in patient and experimental models will refine therapeutic strategies for bone disorders.