Twenty-four hour profile of integrated TSH concentration in puberty.

The 24-h pattern of integrated serum TSH concentrations has been investigated in 12 healthy adult males and 14 pubertal boys by means of continuous blood flow sampling. For every subject the integrated values and the mean concentrations, corresponding to the entire 24 hours, to the daytime (08:00-20:00) and to the nighttime (20:00-08:00) were calculated. A circadian rhythmicity has been shown in boys, as well as in adults. The mean TSH concentrations were significantly higher in boys with respect to adults. The nyctohemeral maximum was mostly recorded in pubertal boys after sleep and in adults before the onset of sleep. Mean and integrated concentrations corresponding to the nighttime period were significantly higher than those corresponding to the daytime in both groups. In conclusion, the 24-h TSH secretion seems different in boys with respect to adults both in the increased concentrations and in the time (generally after the onset of sleep) of the maximum.