a1 Laboratoire de Biochimie, Faculté de Médecine Pitié-Salpétrière 91 boulevard de l'hôpital, 75 013, Paris, France
a2 Laboratoire d'hormonologie, Hôpital Militaire Universitaire Oran, Algeria
Although the effects of short-term fasting on serum leptin concentrations are known, those resulting from long-lasting modifications of food intake schedule, as during the month of Ramadan, have not yet been extensively studied. Therefore, serum concentrations of leptin were measured around the clock at 4-hourly intervals before the beginning of Ramadan and on the twenty-third day of Ramadan daytime fasting in ten male subjects keeping the same usual activity pattern and general synchronisation in both situations. Time series were analysed with repeated measures ANOVA and Cosinor. No significant changes in amplitude or 24 h mean concentration were seen, but significant shifts of 5 h 30 min in peak and trough serum leptin levels were found on the twenty-third day of Ramadan.
(Received April 14 2004)
(Revised October 12 2004)
(Accepted November 19 2004)