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Bone mineral homeostasis, bone growth, and mineralisation during years of pubertal growth: a unifying concept
Insights
Growth hormone and gonadal hormones drive bone growth and mineral balance in children and adolescents. They maintain a high calcium x phosphate product, crucial for mineralization during development.
Area of Science:
- Pediatric Endocrinology
- Mineral Metabolism
- Bone Biology
Background:
- Mineral metabolism differs significantly between children/adolescents and adults.
- Growth hormone and gonadal hormones influence bone and mineral homeostasis.
Purpose of the Study:
- To investigate serum calcium, magnesium, phosphate, and parathyroid hormone levels in children and adolescents compared to adults.
- To propose a unifying concept for the roles of growth hormone and gonadal hormones in pediatric mineral metabolism.
Main Methods:
- Measured serum calcium, magnesium, phosphate, and intact parathyroid hormone in 338 children/adolescents (7-20 years) and 123 adults (21-50 years).
- Analyzed protein-corrected values and the calcium x phosphate product.
Main Results:
- Protein-corrected calcium and magnesium were stable but calcium exceeded adult levels despite hyperphosphatemia in children/adolescents.
- Serum phosphate and the calcium x phosphate product were elevated in children/adolescents, decreasing slowly post-puberty.
- Serum intact parathyroid hormone was high relative to serum calcium levels.
Conclusions:
- Growth hormone is a key regulator of bone growth, mineralization, and mineral homeostasis in youth.
- Gonadal hormones likely mediate some effects via growth hormone, influencing mineral metabolism during development.
- A high calcium x phosphate product is maintained by growth hormone and gonadal hormones to support rapid bone mineralization.
Abstract:
Serum calcium, magnesium proteins, phosphate, and immunoparathyroid hormone were measured in 338 normal children and adolescents aged between 7 and 20 years and in 123 normal adults aged between 21 and 50 years. Protein corrected serum calcium and magnesium remained stable throughout the study. Despite hyperphosphataemia protein corrected calcium exceeded the concentrations of normal adults. Serum phosphate and the Ca X P product greatly exceeded adult values and fell rather slowly towards adult levels after the pubertal growth spurt. Serum immunoparathyroid hormone tended to exceed normal adult values and was judged high for the level of serum calcium. Similarities between mineral metabolism in childhood an adolescence and in acromegaly were striking. On this basis in the light of studies demonstrating stimulatory actions of gonadal hormones on growth hormone and of growth hormone on the secretion of parathyroid hormone and 1,25-dihydroxyvitamin D3, a unifying concept is developed. This concept places growth hormone in the unique position of being the main driver and co-ordinator during childhood and adolescence of bone growth an mineralisation on the one hand, and of blood mineral homeostasis on the other. Gonadal hormones probably express some of their actions through stimulation of growth hormone secretion and others by different mechanisms. According to this concept growth hormone is maintaining th Ca X P product at a suitable high level as long as growth hormone and gonadal hormones deliver bone matrix for mineralisation at a high rate.