Subtype-specific parafollicular localization of the neuropeptide manserin in the rat thyroid gland.

The thyroid gland is an endocrine organ which is involved in metabolism, neuroexcitability, body growth and development. The thyroid gland is also involved in the regulation of calcium metabolism, which is not yet fully understood. In this study, we investigated the localization of the granin-derived neuropeptide, manserin, in the adult rat thyroid gland. Manserin immunoreactivity was detected in thyroid follicular epithelial cells. Intense manserin signals were also detected in some, but not all, parafollicular cells, indicating that parafollicular manserin may be subtype-specific. These results indicate that thyroid manserin may play pivotal roles in parafollicular cells and follicular epithelial cells such as in calcium metabolism and/or thyroid hormone secretion.