Glucocorticoids, thyroid hormone and growth hormone interactions: implications for the growth plate.
Linear growth occurs during childhood and results from endochondral ossification in the growth plate. Prepubertal growth is primarily regulated by growth hormone (GH) and insulin-like growth factor (IGF)-I, with important contributions from glucocorticoids (GC) and thyroid hormone (T(3)). The somatomedin hypothesis proposed that GH stimulates hepatic IGF-I production, which then regulates growth via IGF-I receptor expressing chondrocytes in an endocrine fashion. Recent studies indicate that locally acting IGF-I is a key determinant of endochondral ossification and that GH, GC and T(3) regulate expression of IGF-I and its receptor in the growth plate directly. Analysis of hormone imbalance during childhood and studies of genetically modified mice provide support for an important GH and IGF-I autocrine/paracrine pathway and for direct effects of GC and T(3) during endochondral ossification. Thus, the epiphyseal growth plate is a key site for convergent hormone action that mediates the control of linear growth.
Siebler
T
T
University Children's Hospital, University of Leipzig, Germany.
Robson
H
H
Shalet
S M
SM
Williams
G R
GR
D000818:Animals; D005938:Glucocorticoids / Q000502:physiology*; D013006:Growth Hormone / Q000502:physiology*; D006132:Growth Plate / Q000502:physiology*; D006801:Humans; D011627:Puberty / Q000502:physiology; D013963:Thyroid Hormones / Q000502:physiology*
D005938:Glucocorticoids; D013963:Thyroid Hormones; D013006:Growth Hormone