Ultrastructural localization of calcitonin in control and stimulated thyroid C cells of the rat using protein A-gold immunocytochemical technique.

Using anti-human calcitonin serum and a protein A - gold technique, calcitonin was localized at the ultrastructural level in control and calcium gluconate-stimulated thyroid C cells of the rat. In control rats calcitonin was detected within a majority of the secretory granules while in experimental animals it was demonstrated also within prosecretory granules present in Golgi apparatus.