Acute hepatologic and nephrologic effects of calcitriol in Syrian golden hamster (Mesocricetus auratus)

Abstract

Although vitamin D is included in the group of fat-soluble vitamins, it must be considered as a prohormone. Its active forms including calcitriol have pleiotropic effects and play an important role in the regulation of cell proliferation, differentiation and apoptosis as well as in hormone secretion, and they show anti-cancer properties. Since calcitriol delivery can be beneficial for the organism, and Syrian golden hamsters represent a unique experimental model, we decided to investigate its toxicity in this species. In this study, we injected calcitriol intraperitoneally at doses 0 (control), 0.180±0.009 µg/kg and 0.717± 0.032 µg/kg. Animal behavior was observed for 72 hrs after injection, and afterwards blood and liver and kidney were collected for post-mortem examination, electron microscopy, and hematology analyses. The highest dose of calcitriol induced a change in animal behavior from calm to aggressive, and liver surface showed morphological signs of damage. Following the injection of calcitriol, ultrastructural changes were also observed in the liver and kidneys, e.g. vacuolization and increased number of mitochondria. There was also a trend for increased serum levels of aspartate aminotransferase (AST), but not of alanine aminotransferase (ALT) or GGTP (gamma-glutamyl transpeptidase). There was no change in Ca, Mg and P levels as well as in blood morphology between experimental and control groups. These results indicate that calcitriol at 0.717, but not at 0.18 µg/kg, may induce acute damage of the liver and kidneys, without inducing calcemia. We propose that the hepatotoxic effect of calcitriol in hamster constitutes the primary cause of behavioral changes.