Effects of 1,25- and 24,25-dihydroxyvitamin D3 on bone formation in the cichlid teleost Sarotherodon mossambicus

Abstract

1,25-Dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 have antagonistic effects on the acellular bone of the tilapia Sarotherodon mossambicus. 1,25-Dihydroxyvitamin D3 inhibits the activity of the lining osteoblasts. Prolonged administration leads to demineralization of the bone matrix. Injection of 24,25-dihydroxyvitamin D3 induces structural signs of greatly enhanced appositional bone growth within three days. No effects were observed on the mineral content of pre-existing bone. Both 1,25- and 24,25-dihydroxyvitamin D3 may have distinct, but different physiological functions in fish.

Continuous light induces bone resorption and affects vertebral morphology in Atlantic salmon (Salmo salarL.) fed a phosphorous deficient diet

“…Interestingly, 1,25(OH) 2 D 3 can utilize bony tissue as a source for P; both anabolic and catabolic effects of 1,25 (OH) 2 D 3 on fish bone have been described. Increased vertebral bone resorption was shown in European eel (Anguilla anguilla Linneaus) (Lopez et al 1977) and Mozambique tilapia (Oreochromis mossambicus Peters) (Wendelaar Bonga et al 1983), while increased bone mineralization was found in European eel (A. anguilla Linneaus) (Lopez et al 1980), emerald rockcod (Pagothenia bernachii Boulenger) (Fenwick et al 1994) and zebrafish (Danio rerio Hamilton) (Fleming et al 2005) after 1,25(OH) 2 D 3 administration. Furthermore, a recent study by Darias et al (2010) showed that low dietary vitamin D 3 impaired bone mineralization in European sea bass (Dicentrarchus labrax) juveniles.…”

Functional bone histology of zebrafish reveals two types of endochondral ossification, different types of osteoblast clusters and a new bone type

“…Apart from the presence/absence of osteocytes, we show that there are some other further differences, but also some similarities, between cellular and acellular bone types. For example, both are covered by a thin periosteal layer of osteoblast-like cells and both have osteoblasts on the outer bone surfaces (Wendelaar et al 1983;). However, our detailed examination showed that osteoblasts are absent (or very rare) on the outer bone surfaces of acellular bones in the zebrafish.…”

Endocrinology of the Vertebrates

“…In teleost fishes, some reports show increased intestinal calcium absorption following treatment with some metabolites, while others show inhibitory effects of other metabolites (123,287,290,835). In eels, binding of calcitriol has been described in a variety of tissues, including liver, brain, and gut but interestingly not in bone, kidney, and skin (562), while other studies suggest that known and other as yet unidentified metabolites have primary actions on bone and possibly elsewhere to induce hypercalcemia (540,901).…”