[Concentration of C cells in the thyroid of rats treated with mercaptoimidazole or levo-thyroxine]

Concentration of C cells in the thyroid of rats treated with Mercaptoimidazole or Levo-thyroxine. The aim of the present study was to elucidate the possible functional relationship between follicular and parafollicular cells of the thyroid gland; therefore we have investigated the behaviour of calcitonin producing cells and serum calcitonin concentration in rats both in resting and hyperstimulation conditions of follicular cells. Our results showed that with regard to follicular mass the concentration of the C cells was reduced in the two groups of rats treated compared to control rats. C cell concentration decrease was associated with reduced serum calcitonin concentration. In conclusion C cell activity is independent of TSH and thyroid hormones circulating levels.