Summary
The initial hormonal changes in male puberty occur at nighttime, with episodic rises
of LH and testosterone (T). Only much later do the daytime levels of these hormones
rise. Nocturnal sampling is impractical for routine clinical assessment, so we have
examined the relationship between peak nocturnal T levels and those produced in the
same subject by a single intravenous injection of gonadotrophin releasing hormone
(GnRH, 100 μg) in the morning. Nocturnal T profiles and daytime GnRH tests have been
conducted in eight boys in early (delayed) puberty, three with pubertal gynaecomastia
in later puberty, two normal men, and one man with gynaecomastia. Excellent agreement
was obtained between peak nocturnal and post-GnRH T levels. The serum testosterone
level 3 hours after 100 μg IV GnRH is a simple and useful hormonal marker of pituitary-Leydig
cell activity during puberty.
Key-Words:
Early Male Puberty
-
Nocturnal LH and Testosterone
-
GnRH Stimulation
-
Pubertal Gynaecomastia
-
Delayed Puberty
