[Circadian rhythm of serum levo-carnitine: parameters]

The present study investigates the circadian rhythm (CR) of levo-carnitine (L-c) in systemic venous blood, in order to detect rhythmometric parameters that can be used for programming an eventual chronoterapy with such a molecule.

The L-c CR was investigated in 10 clinically healthy subjects (5 M; 5 F; mean age: 26.02 +/- 1.11 yrs), who were diurnally active and nocturnally resting. Blood samples were taken at 06:00; 08:00; 12:00; 18:00; 20:00; 24:00, not juxtaposed to breakfast, lunch and dinner. The serum concentrations of L-c were assayed via a spectrophotometric method.

A nychtohemeral variability in circulating levels of L-c was observed, with a peak in the afternoon. Such a intradiem variability was validated to have the properties of a significant CR (MESOR = 33.37 mumol/l with a SEM of 1.19 mumol/l; amplitude = 6.31 mumol/l with 95%CL ranging from 3.58 mumol/l to 9.69 mumol/l; acrophase at 15:52 h:min with 95%CL ranging from 13:28 h:min to 17:00 h:min).

It is important to remark that the validation of a CR for the systemic serum levels of L-c was obtained in diurnally-active/nocturnally resting subjects. Such validated rhythmometric properties are parameters that can be used for programming an eventual chronotherapy, considering that the molecule L-c is used for treating its various types of primary and secondary deficiency.