Ultimobranchial bodies

In most mammals, calcitonin is synthesized by specialized parafollicular cells in the thyroid. In sub-mammalian species, it is synthesized by specialized anatomical structures known as ultimobranchial bodies. 

Progress in the field has been rapid. Calcitonin has been isolated from the thyroid or the ultimobranchial body in more than twenty species (F5) including man. Calcitonin was purified, and the amino acid sequence was determined (N2, P7). The molecular weight is approximately 3600. The synthesis of calcitonin was reported within the past year (B6, R7). Recent reviews on calcitonin are available (F5, M2). 

A great deal of work using LeDouarin s method proved that C cells of the thyroid gland and of the ultimobranchial body, type 1 cells of the carotid body, and adrenal medullary N and NA cells are derived from the neural crest. Pearse admitted that the APUD cells of the stomach, intestine, and pancreas are beyond doubt not derived from the neural crest. Instead, they come from neuroendocrine programmed ectoblast. ... 

Calcitonin is produced in the parafollicular or C cells of the thyroid gland which are homologous with the ultimobranchial body of birds and fish. The hormone has been isolated from a variety of species and always consists of a single chain of 32 amino acids, although there are considerable variations in its amino acid composition and relative activity when administered to rats. 

Although the thyroid gland is probably the most important source of calcitonin, the parathyroid glands and the thymus, which contain C cells as vestiges of the ultimobranchial body, also produce the hormone. 

Pearse and colleagues (Pearse, 1966 Bussolati and Pearse, 1967 Pearse and Carvalheira, 1967) showed that the thyroid C cells secreted calcitonin and that these cells were of ultimobranchial origin. It has now been found that calcitonin can be extracted from the ultimobranchial body in chickens (Copp, 1968 Matthews, Moseley, Breed and MacIntyre, unpublished) and pigeon (Matthews et al). 

Inhalable co-spray dried powders of salmon calcitonin-loaded chitosan nanoparticles with mannitol have been prepared and analyzed. Salmon calcitonin or Calcitonin (also known as thyrocalcitonin) is a 32-amino acid linear polypeptide hormone that is produced in humans primarily by the parafollicular cells (also known as C-cells) of the thyroid, and in many other animals in the ultimobranchial body. It acts to reduce blood calcium (Ca ), opposing the effects of parathyroid hormone (PTH) [118]. The... 

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