Altun, AYaprak, MAktoz, MVardar, ABetul, UOzbay, G2024-06-122024-06-1220020304-3940https://doi.org/10.1016/S0304-3940(02)00368-3https://hdl.handle.net/20.500.14551/22680We investigated nocturnal secretion pattern of melatonin in patients with cardiac syndrome X and healthy subjects. The present study performed in five patients with cardiac syndrome X and in nine healthy controls. Blood samples from all subjects were collected every 2 h intervals between 22:00 and 08:00 h. Melatonin levels were measured with a radioimmunoassay kit. Patients with cardiac syndrome X secreted less nocturnal melatonin at 02:00 h than control subjects (P = 0.04). Peak and Delta melatonin (peak-lowest melatonin) were found lower in patients with cardiac syndrome X (P = 0.039 and P = 0.028, respectively). In conclusion patients with cardiac syndrome X show a markedly decreased nocturnal melatonin synthesis. Our study provides useful information about melatonin synthesis and release in patients with cardiac syndrome X might help physicians in managing these patients. (C) 2002 Published by Elsevier Science Ireland Ltd.en10.1016/S0304-3940(02)00368-3info:eu-repo/semantics/closedAccessNervous SystemSympathovagal ImbalanceAnginaNormal Coronary AngiographyCoronary-Artery DiseaseHeart-DiseaseArticle3272143145Q2WOS:0001773698000172-s2.0-003713528812098655Q2