Clinical Significance of C-Peptide
Significant information has accumulated in recent years regarding the biochemical and morphological details of insulin biosynthesis and secretion. Insulin is formed in pancreatic beta-cells through enzymatic splitting of a precursor molecule, proinsulin, which itself is a product of the proteolysis of an even larger molecule, preproinsulin (Chan, Keim, and Steiner, 1976; Steiner, 1977; Steiner, Clark, Nolan, Rubenstein, Margoliash, Melani, and Oyer, 1970; Steiner, Kemmler, Clark, Oyer, and Rubenstein, 1972; Steiner and Oyer, 1967). This latter reaction occurs as the molecule traverses the membrane of the rough endoplasmic reticulum. Proinsulin is transported through the cisternal space to the Golgi apparatus, where it is packaged into granules. As the granules mature, proinsulin is cleaved into insulin and C-peptide (Howell, Kostianowski, and Lacy, 1969; Orci, Lambert, Kanazawa, Amherdt, Poviller, and Renold, 1971; Steiner et al., 1972).
KeywordsBeta Cell Beta Cell Function Insulin Antibody Secretory Ability Residual Beta Cell Function
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