Estimation of influence of high doses of cholecalciferol on thyroid parafollicular and respiratory tract neuroendocrine cells; preliminary investigations.

The aim of this study was to compare what changes are caused by high doses of cholecalciferol (100,000 UI vD3) and CaCl2 on thyroid parafollicular (C) cells and airways neuroendocrine (NE) cells in rat. Overdosage of vD3 and CaCl2 causes hypocalcaemia and strong hypercalcitoninemia in blood; C cells showed mainly signs of hypertrophy; simultaneously, the number of strong calcitoninpositive cells decreased significantly (statistically significant changes). Immunohistochemical reactions, detecting CGRP, somatostatin, synaptophysin and neuronspecific enolase did not fall under statistic analysis. Airways NE cells re-acted to hypercalcemia differently than C cells--they probably respond to different regulatory mechanisms.