[Effect of growth hormone and calcitriol on the growth plate in uremic rats]

This study analyzed the modifications induced by growth hormone (GH) and/or calcitriol treatments in the growth plate of growth retarded uremic rats. Four groups of 5/6 nephrectomized rats were studied: untreated (U), treated with GH (U + GH), treated with calcitriol (U + D), treated with GH and calcitriol (U + GH + D). Treatments were given intraperitoneally during the second week of renal failure. Uremic groups were compared with sham-operated rats fed ad libitum (C) or pair-fed with U (CP). In comparison with C and CP, histomorphometric analysis of tibial proximal ends of U group showed decreased bone formation, as estimated by osseous front advance (OFA), elongation of growth cartilage and its hypertrophic zone, and decreased size of most distal chondrocytes. The U + D group tended to normalize growth cartilage height, and that of its hypertrophic zone, as well as the size of chondrocytes. In U + GH group OFA improved and chondrocyte size became normal, but growth cartilage remained elongated. Similar results were found in the U + GH + D group. These findings indicate that, in chronic renal insufficiency, the beneficial effect of GH on growth is not associated with normalization of growth cartilage morphology and that calcitriol facilitates chondrocyte maturation. When given together the effect of GH prevails.