Developmentally Delimited Emergence of More Orderly Luteinizing Hormone and Testosterone Secretion during Late Prepuberty in Boys

J. D. Veldhuis
2001 Journal of Clinical Endocrinology and Metabolism  
To quantitate changing feedback control in the GnRH-LH/FSHtestosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we
more » ... dingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early prepuberty (genital stage I-A: mean bone age, 4.6 Ϯ 1.6 yr; testis volume, Ͻ3 mL for at least 3 succeeding yr) and late prepuberty (genital stage I-C: bone age, 8.7 Ϯ 1.8 yr; testis volume, Ͻ3 mL for up to 1 yr thereafter; P ϭ 0.00019), which indicates the acquisition of more regular LH release patterns in late prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 Ϯ 1.0 yr; testis volume, 2.8 Ϯ 0.4 mL). The LH secretory process was more disorderly in mid-and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P Ͻ 10 Ϫ7 ), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the
doi:10.1210/jc.86.1.80 pmid:11231982 fatcat:nrlszmjrwvcsjakmhyu4alnjaa