I too believe that calcitonin has postparandial efefcts in human. It evolved during the evolution as it is also present in protochordates and some lower forms. It is conserved in higher vertebrates and may be having some other roles because in lower vertebrates several functions have been ascribed to this hormone and still those functions have to be established in human
Yes you are absolutely right. I would like to add that if the hormone is conserved it must has some role that we have to explore now. In salmon there is salmon I, II and III CTs hence they all may have some different roles.
May I know the field of your study. I worked with Prof. Ziegler at Heidelberg University (Internal Medicine I). Now I am working in the field of endocrine toxicology mainly ultimobranchial, corpuscles of Stannius and prolactin etc. My earlier work was on calcium regulating endocrine glands in mammals. So it would be nice if you are working in the same field or may be some related field.