Calcitonin distribution within pig, sheep and cow thyroid

The distribution of calcitonin within the pig, sheep and cow thyroid was examined by measuring the concentration of the hormone in serial sagittal and transverse 5-mm sections of whole thyroids. It was observed that calcitonin in the pig thyroid was concentrated in the anterior to right lateral parts of the thyroid. Calcitonin was localized in the central region of the sheep thyroid with a relatively lower concentration in the peripheral parts of the gland. In the cow thyroid a uniform distribution of calcitonin was observed. The results of this study indicate a species specific and characteristic distribution of calcitonin within the thyroid of the pig, sheep and cow.