[Immunohistochemical demonstration of calcitonin cells in the fetal thyroid of mice].

Calcitonin was revealed by means of an indirect immunohistochemical method using a serum against synthetic human calcitonin. After the use of the Bouin-Hollande fixative liquid, the hormone was detected in cells located in the central part of the thyroïdian wings. They are few at the 18th day of fetal life, their number increases regularly until reaching ten times the initial number at birth. The immunological reaction is negative if only aldehyde fixatives are used.