Growth Hormone and the Acquisition of Bone Mass

Abstract

Bone remodelling is a continuous, closely coupled process of bone resorption followed by bone formation. This process is regulated by factors and hormones which include GH, IGF-I and gonadal steroids. GH deficiency in childhood results in short stature and delayed bone maturation and a reduced peak bone mass might account for reduced BMC and BMD. Possible pathophysiological mechanisms for reduced bone mass in both childhood- and adult-onset GH deficiency are discussed. GH treatment effects on bone metabolism include increased remodelling, with increases in BMC, BMD and bone area. Increases in BMC and BMD are delayed while these changes are incorporated into the skeleton. BMC increases to a greater extent than BMD. At a cellular level, GH and IGF-I have direct and indirect effects on osteoblast and osteoclast precursors and fully differentiated cells. Osteoblasts possess both oestrogen and androgen receptors and bone loss accelerates with the loss of gonadal function. There are gender differences in GH effects on bone. BMD is related to fracture risk in the hip and lumbar spine in women. GH treatment might decrease fracture risk at a level comparable to oestrogen or bisphosphonate treatment. Patients with the lowest BMD prior to treatment derive the greatest benefit from GH therapy.

Total Body Bone Mineral Content and Tibial Cortical Bone Measures in Preschool Children

“…Cadogan and coworkers found higher serum insulin‐like growth factor 1 (IGF‐1) concentrations among girls randomized to receive 1 pint of milk per day for 18 months compared with girls not receiving milk (31) . Growth hormone and IGF‐1 are involved in bone remodeling and promote bone growth (32) . Thus, it is possible that the association we observed between TBBA and calcium intake is a reflection of the effects of other nutrients or growth factors present in dairy products or results from dairy product consumption rather than from calcium intake alone.…”

Bone mineral density in patients with growth hormone deficiency: does a gender difference exist?

“…This paracrine and autocrine oestrogen action may be mediated by a tissue‐specific aromatase, and in fact aromatase expression is demonstrated in human osteoblast‐like cells 40 . It is also well known that both GH and IGF‐1 have direct and indirect effects at cellular levels of the osteoblasts and osteoclasts 27,36 . It is therefore possible that the bone‐specific aromatase activity is influenced by the action of GH and/or IGF‐1.…”

“…40 It is also well known that both GH and IGF-1 have direct and indirect effects at cellular levels of the osteoblasts and osteoclasts. 27,36 It is therefore possible that the bone-specific aromatase activity is influenced by the action of GH and/or IGF-1.…”

Bone development during GH and GnRH analog treatment

“…Reduced BMD by DEXA in GHD adults may be explained either by a failure to achieve normal PBM or by subsequent bone loss during adult life (45,46), and the severity of bone loss is proportional to the biochemical severity of GHD (49).…”