BIOLOGICAL ASSAY FOR LH IN PEDIATRICS

Biological assay for LH consists in measuring the testosterone production of dispersed Leydig cells of rats, stimulated by human leutinizing hormone. We have applied this method in Pediatrics to monitorize normal pubertal development and to study some aspects of hypothalamic-hypophysis-gonads axis disturbance. One hundred fifteen subjects between 4 and 19 years were studied. Seventy five (41 males and 34 females) were subdivided into 5 groups (P1<8 years, P1>8 years, P2-3, P4-5, adult) according to their pubertal development and were considered as control group. Furthermore 12 patients affected by precocious puberty, 14 by premature thelarche or adrenarche, 8 by Turner' syndrome were studied. Three separated blood samples were drawn (at times -30, -15, 0) from each subject. Results were expressed as mean +/- SD of the mean of three samples. In figures 1, 2, 3, 4, 5 are shown all results. Our data confirm that biological assay for LH increases during pubertal development earlier than the the immunoreactive one determining an increase in B/I ratios. The biological assay for LH is a good tool to differentiate the diagnosis of precocious puberty in respect to thelarche or adrenarche and to monitorize treatment with LH-RH analog. In hypergonadotropinic hypogonadism, this method could give new information on the modulation of sexual steroids on LH-RH secretion.