ABSTRACT

Parathyroid hormone (PTH) is the major secretory product of the chief cells of the parathyroid glands and is transcribed from a gene located on chromosome 11 [1]. The major translation product is an 84-amino acid straight chain polypeptide [PTH (1-84)] extended at the amino (NH2)-terminus by a leader (signal) or pre-sequence that facilitates its entry into the secretory apparatus of the cell, and by a short prohormone sequence, both of which are cleaved before exit from the parathyroid cell. The entire precursor of PTH (1-84) is called preproPTH. The 84 amino acid moiety is both the major glandular form and the major bioactive secreted and circulating form, although perhaps some short-lived NH2-terminal fragments circulate under special circumstances [2].