Cardiac hormones: morphology and biochemistry.
The heart contains, in addition to its myocardial working cells and the conductive system, a specialized endocrine part localized mainly in the atrial appendage which is predominantly made up by myoendocrine cells. The ultrastructural and immunocytochemical analysis of myoendocrine cells show a specialized secretory apparatus involved in the synthesis and secretion of cardiac hormones. These cardiac hormones are synthesized and processed in the myoendocrine cells as follows: a preprohormone is found in the rough endoplasmic reticulum, the prohormone cardiodilatin/gamma-atrial natriuretic polypeptide (CDD/ANP) is processed in the Golgi apparatus and stored in the secretory granules. The circulating peptide, cardiodilatin 99-126/alpha-ANP, is the C-terminus of this preprohormone which is released as the active circulating form into the blood stream.
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism; D006325:Heart Atria / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D006651:Histocytochemistry; D006801:Humans; D007120:Immunochemistry; D009124:Muscle Proteins / Q000378:metabolism*
D009124:Muscle Proteins; D009320:Atrial Natriuretic Factor; C040651:cardiodilatin