Effects of growth hormone treatment on growth plate, bone, and mineral metabolism of young rats with uremia induced by adenine.

ABSTRACT

BackgroundIn a model of growth retardation secondary to chronic kidney disease (CKD) induced by adenine, this study explores the effects of growth hormone (GH) therapy on growth plate and mineral metabolism.MethodsWeaning female rats receiving a 0.5% adenine diet during 21 days, untreated (AD) or treated with GH (ADGH) for 1 week, were compared with control rats receiving normal diet, either ad libitum or pair-fed with AD animals. AD and ADGH rats had similarly elevated serum concentrations of urea nitrogen, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23).ResultsUremia induced by adenine caused growth retardation and disturbed growth cartilage chondrocyte hypertrophy. We demonstrated marked expression of aquaporin 1 in the growth plate, but its immunohistochemical signal and the expression levels of other proteins potentially related with chondrocyte enlargement, such as Na-K-2Cl cotransporter, insulin-like growth factor 1 (IGF-1), and IGF-1 receptor, were not different among the four groups of rats. The distribution pattern of vascular endothelial growth factor was also similar. AD rats developed femur bone structure abnormalities analyzed by micro-computerized tomography.ConclusionGH treatment accelerated longitudinal growth velocity, stimulated the proliferation and enlargement of chondrocytes, and did not modify the elevated serum PTH or FGF23 concentrations or the abnormal bone structure.