[Nocturnal luteinizing hormone secretion patterns at the onset of puberty measured using a highly sensitive...

Nocturnal LH pulse was analyzed in 4 prepubertal, 3 early pubertal and 2 midpubertal boys by measuring serum LH concentrations. Blood samples were taken every 30 minutes while awake, and every 20 minutes after subjects had gone to sleep. Serum LH was measured by using immunofluorometric assay (IFMA) with a lower detection limit of 0.02mIU/ml. Pulsatile LH secretion during sleep was detected in all subjects examined. LH pulse amplitude had the tendency to increase with the advance of pubertal stage. After the onset of puberty, LH pulse amplitude was significantly larger than before. The LH pulse was also detected while awake in 4 (1 prepubertal, 2 early pubertal and 1 mid-pubertal) boys. LH pulse frequency was almost the same in each pubertal stage. Serum testosterone levels gradually increased with the progress of pubertal stage. These results suggest that 1) LH is secreted in a pulsatile manner in the prepubertal subjects as well as in the pubertal subjects, 2) the increase of LH pulse amplitude plays an important role for the onset of puberty, and 3) LH pulse amplitude could be a biological marker that indicates the degree of maturation of the hypothalamo-pituitary unit in prepubertal children.