Haemodynamic effects of Melatonin

In thi.s work the effect of melatonin administration in adult JDale rats at two dose levels 3mg/kg or 30mglkg for one month was investigated on :1- Lipid profile : by measuring the serum level of total cholesterol, triglyceride, low density lipoprotein cholesterol and high density lipoprotein cholestaol.I 2-Blood vessels : by measuring the carotid blood flow using doppler ultrasonic waves as a new technique.3-Kidney function: by measuring the serum level of creatnine. 4-Blood coagulation: by measuring bleeding time, partial thromboplastin time and prothrombin time .. ~-Liver function: by measuring the serum level of OPT, GOT and albumin.6-Blood cell count : by counting red blood cells, platelets, white blood cells, differential count of white blood cells and ’reticulocyte count.7-Blood bilirubin : by measuring the serum level of total, direct and indirect bilirubin.8-Haemoglobin : by measuring blood haemoglobin value.Histopathological investigation of different organsincluding heart, liver and blood vessels was performed to detect any changes caused by melatonin adm inistration.Also haemogram was performed to investigate the effect of melatonin on the shape of blood cells.1- Oral’ administration otJ melatonin in a dose of3mg/kg for one month as a single daily dose in the morning induced a• significant decrease in senlm total cholesterol level.However, the higher dose 30mg/kg had no significant effect·.2- Melatonin in a dose of 3mg/kg or 30mglkg induced a signiticant decrease in serum level of triglycerides.3- Both doses 3mglkg and 30mg/kg induced a signiticant decrease in the serum level of LDL - C .4- The serum level of HDL-C not affected by the administration of melatonin in a dose of 3mg/kg. However, the administration of the higher dose (30mg/kg) induced a significant increase in the serum level of HDL-C.5- Oral administration of m~latonin in the two doses 3mg/kg or 30mglkg induced a significant increase in the carotid blood flow. However, the administration of both doses had no significant effect on carotid blood flow when the animals are injected with Illg/kg pheneylepherine i.v or with 21lglkg isoxuprine i.v 10 minutes before taking the trace.6- Melatonin administration in a dose of 3mglkg or 30mglkg had no significant effect on serum level of creatnine.7 - Both doses 3mg/kg and 30mglkg induced a signiticant increase in platelet numbers.8- The administration of the two doses of melatonin 3mglkg or 30mglkg induced a signiticant increase in bleeding time and a significant prolongation in prothrombin time and partial thromboplastin time.