RESUMO
<p><b>OBJECTIVE</b>To investigate the changes of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), estradiol (E2) and testosterone (T) in male adolescents of different ages by determining their levels in 8-17 years old boys.</p><p><b>METHODS</b>We included in this study 627 male adolescents aged 8-17 years and qualified through physical examinations. All the subjects underwent determination of FSH, LH, PRL, E2 and T with an automatic ACCESS microparticle chemiluminescence immunoassay analyzer and detection of liquid quality control by immunoassay.</p><p><b>RESULTS</b>FSH remained at a low level in the 8-10 years old male adolescents and increased at 11 years; the levels of LH and T were low before the age of 12 years and began to increase at 13 years; and that of E2 was low before the age of 13 years and began to rise after that, all with statistically significant differences (P < 0.01).</p><p><b>CONCLUSION</b>In the male adolescents, FSH, LH and T significantly increased at 11, 12 and 13 years old, respectively, which marked the beginning of sexual development.</p>