[Endocrine aspects of puberty. Modifications of gonadotropins (LH, FSH), testosterone and cortisol circulating after ACTH and synthetic LH-RH].

The effect of synthetic LH-RH (Relisorm Serono: 25 microgram i.v.) on plasma LH, FSH and testosterone was examined in 19 normal pubescent and prepubescent boys. Changes in cortisol and testosterone after 0.25 mg/m2 body surface ACTH (Synacthen ciba) was assessed in a further 8 prepubescent subjects. Notable amounts of FSH, LH and testosterone were noted in prepubescent subjects, pointing to hormonal production prior to sexual maturation. There was a prompt and significant increase in LH in all cases. In prepubescent subjects, this was accompanied by marked increases in FSH on some occasions, though no appreciable change in circulating testosterone. This suggests that the hypophyseal reserve of LH is sufficient in puberty. Prepubescent subjects displayed a significant rise in cortisol 30' and 60' after ACTH, whereas testosterone fell with respect to the start values. The results indicate that acute stimulation of the adrenal cortex before puberty leads to testosterone suppression.