COMPARISON OF THE EFFECT OF BETA-ALANYL-L-HISTIDINATO ZINC AND ITS ZINC-CHELATING LIGAND ON BONE METABOLISM IN TISSUE-CULTURE

The present investigation was undertaken to compare the effects of beta-alanyl-L-histidinato zinc (AHZ) and its zinc-chelating ligands on bone metabolism in tissue culture. Calvaria were removed from 3-week-old male rats and cultured for up to 72h in Dulbecco's modified eagle medium containing zinc sulfate, AHZ, di(N-acetyl-beta-alanyl-L-histidinato)zinc (AAHZ), and di(histidino)zinc (HZ). The bone calcium content and alkaline phosphatase activity were significantly increased in the presence of AHZ or AAHZ (10(-8)-10(-5) M). Those increases were seen at 10(-7) to 10(-5) M zinc sulfate and HZ. The bone deoxyribonucleic acid (DNA) content was significantly increased by AHZ or AAHZ with 10(-7) to 10(-5) M, while 10(-7) M zinc sulfate and HZ had no effect. Thus, AHZ and AAHZ had more potent effect than that of zinc sulfate and HZ. The effect of AHZ, AAHZ and HZ (10(-5) M) increasing bone alkaline phosphatase activity was abolished by the presence of 10(-4) M dipicolinate, a chelator of zinc. Moreover, the effect of these zinc compounds on bone metabolic indices was not seen in the presence of 10(-6) M cycloheximide. The present results suggest that the effect of AHZ and AAHZ on bone metabolism is more potent than that of zinc sulfate and HZ.