Pineal response after pyridoxine test in children.
To characterize the pineal response to pyridoxine, plasma melatonin was measured in one hundred and twenty children 3 hours after vitamin B6 administration. The children, aged between 1.5 and 8 years, were divided in four groups as follows: a) control day group, grouping 27 children sampled at 9:00 and at 12:00; b) control night group, grouping 29 children sampled at 21:00 and at 24:00; c) pyridoxine day group, grouping 30 children sampled at 9:00, then intravenously (i.v.) injected with 3 mg/kg of pyridoxine, and sampled at 12:00; and d) pyridoxine night group, grouping 34 children sampled at 21:00, i.v. injected with 3 mg/kg of pyridoxine, and sampled at 24:00. Melatonin concentration was measured by radioimmuno assay. The data obtained showed a significant increase in melatonin levels after pyridoxine administration in the pyridoxine night group (39.87 +/- 8.02 pg/ml basal vs 88.45 +/- 9.21 pg/ml after pyridoxine, p < 0.001). The other groups did not showed significant differences in melatonin concentrations. Statistical analysis shows that the administration of pyridoxine during the nocturnal hours represents a stimulating factor to increase the pineal production of melatonin in children.
Muñoz-Hoyos
A
A
Departamento de Pediatría, Hospital Universitario, Facultad de Medicina, Universidad de Granada, Spain.
Amorós-Rodríguez
I
I
Molina-Carballo
A
A
Uberos-Fernández
J
J
Acuña-Castroviejo
D
D
D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008550:Melatonin / Q000096:biosynthesis*; D010870:Pineal Gland / Q000187:drug effects*; D011736:Pyridoxine; D012044:Regression Analysis; D014364:Tryptophan / Q000378:metabolism*
D014364:Tryptophan; D008550:Melatonin; D011736:Pyridoxine