Immunohistochemical alterations of C cells in sheep treated with vitamin D.

Hyperplasia and hypertrophy of C cells were demonstrated in sheep with hypercalcaemia induced by administration of vitamin D3 (2 million I.U. per day). After treatment with vitamin D3 for 10, 20 or 30 days, serum calcium values increased to 10.28, 11.86 and 10.44 mg per dl, respectively, compared to a normal concentration of around 9 mg per dl. Immunohistochemical reactions of calcitonin, chromogranin A and calcitonin gene-related peptide (CGRP) decreased, whereas intense neurone-specific enolase (NSE) immunoreactivity was noted in C cells. Immunohistochemical staining with anti-calcitonin, anti-chromogranin A, anti-CGRP and anti-NSE antisera was useful to demonstrate the functional state of stimulated C cells in sheep with hypercalcaemia.