title: Distribution of calcitonin-containing cells in the normal neonatal human thyroid gland: a correlation of morphology with peptide content.
abstract: C-cells have been mapped in the thyroid glands of 6 human neonates by means of immunoperoxidase localization of calcitonin and tissue calcitonin content as measured by radioimmunoassay. The C-cells were concentrated in a zone in the upper two-thirds of the lateral lobes bilaterally, where they were identified individually and in small groups in both an intrafollicular and parafollicular distribution. In contrast to findings in the adult, C-cells were predominantly intrafollicular in the neonate. The relative numbers of C-cells counted per unit area of thyroid tissue correlated strongly with the calcitonin content of immediately adjacent tissue sections. In areas rich in C-cells, as many as 75 immunoperoxidase-stained cells per low-power field were counted, and the concentration of calcitonin was as high as 540 to 2100 mU/g fresh weight, values that were as great as 10 times those observed in the normal adult thyroid gland. The prominence of the C-cell population and increased tissue calcitonin content in the human neonatal thyroid gland may reflect an as yet undefined physiologic role for calcitonin in the newborn.
mesh_terms: D002116:Calcitonin / Q000032:analysis*; D002452:Cell Count; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010544:Peroxidases; D011863:Radioimmunoassay; D013961:Thyroid Gland / Q000032:analysis / Q000166:cytology*
chemical_list: D002116:Calcitonin; D010544:Peroxidases