This preliminary study investigates effects of methyl- and cyanocobalamin on circadian rhythms, well-being, alertness, and concentration in healthy subjects. Six women (mean age 35 years) and 14 men (mean age 37 years) were randomly assigned to treatment for 14 days with 3 mg cyano-(CB12) or methylcobalamin (MB12) after 9 days of pre-treatment observation. Levels in the CB12 group increased rapidly in the first, then slowly in the second treatment week, whereas increase in the MB12 group was linear. Urinary aMT6s excretion was reduced by both forms of vitamin B12 over 24 hours with a significant decrease between 0700-1100 hours, whereas urinary excretion of potassium was significantly increased between 0700-1100 hours. Activity from 2300-0700 hours increased significantly under both forms of vitamin B12. Sleep time was significantly reduced under MB12 intake. In this group the change in the visual analogue scales items "sleep quality," "concentration," and "feeling refreshed" between pretreatment and the first week of treatment showed significant correlations with vitamin B12 plasma levels. Cortisol excretion and temperature were not affected by either medication. We conclude that vitamin B12 exerts a direct influence on melatonin. Only MB12 has a positive psychotropic alerting effect with a distribution of the sleep-wake cycle toward sleep reduction.

1995-06-01·Neuroscience letters4区 · 医学

Effects of vitamin B12 on human circadian body temperature rhythm

4区 · 医学

Article

作者: Geert Mayer ; Masako Okawa ; Karlheinz Meier-Ewert ; Makoto Uchiyama

To clarify the effect of vitamin B12 on the human circadian clock, five healthy male adults participated in two constant routine procedures, 2 or 3 weeks apart. In one, subjects received intravenous saline injections (placebo trial) and in the other, intravenous injections of methylcobalamin (MB12) (drug trial). Intravenous administration of MB12 increased rectal temperature in the later hours of the daytime during the constant routine. The activity did not change between treatments in any period during the constant routine. During the later hours of the constant routine, alertness assessed with visual analog scale was higher in the drug trial than in the placebo trial. The period in which drug treatment produced greater alertness almost coincided with that in which MB12 elevated rectal temperature. These results may provide evidence of an effect of vitamin B12 on the circadian clock.

1989-05-01·Pathologie-biologie

[Influence of food intake on the bioavailability of ponsinomycin administered in a syrup form].

Article

作者: Couet, W ; Bizouard, J ; Reigner, B ; Girault, J ; Fourtillan, J B ; Ingrand, I

Ponsinomycin is a new macrolide. Following oral administration, ponsinomycin is totally metabolized, even before reaching blood circulation. Metabolite Mb12 is the first compound on the main metabolic route, which can be assayed. The influence of food on ponsinomycin bioavailability has therefore been estimated from measurements of Mb12 plasma levels. Twelve young healthy volunteers received 800 mg of ponsinomycin as a syrup on two separate occasions, 2 hours before and during a standard meal. The Mb12 metabolite was assayed in plasma by High Pressure Liquid Chromatography (HPLC). Plasma peak concentrations and areas under curves were not significantly different but time to peak was significantly shorter when ponsinomycin was administered during meal. The results suggest that ponsinomycin absorption is faster when administered with food but quantitatively unchanged.

100 项与 MB-12 相关的药物交易

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