Dynamic testing in the evaluation of male gonadal function.
The maturation and physiologic functions of male sexual apparatus are under the control of the hypothalamic-pituitary-gonadal (HPG) axis. The determination of gonadotropins and testosterone as secretory products of pituitary and gonads, respectively, represents the first step in the evaluation of male sexual function and the diagnosis of disorders in male reproductive axis. However, there are several clinical situations that require a dynamic evaluation of this system and the measurement of basal gonadotropins and testosterone must be combined with specific dynamic tests. These mainly consist in GnRH stimulation, which evaluates the endocrine reserve capacity of the pituitary, and human chorionic gonadotropin (hCG) stimulation, which is used in the assessment of Leydig cells activity. The paper illustrates the technical aspects, the normal/pathological responses and the role of these two tests in assessing the male HPG axis in respect to different clinical diagnostic queries.
De Martino
M U
MU
Endocrinology Unit, Department of Internal Medicine, Tor Vergata University, Rome, Italy.
Pastore
R
R
Caprio
M
M
Frajese
G
G
Fabbri
A
A
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D006063:Chorionic Gonadotropin; D025461:Feedback, Physiological; D005640:Follicle Stimulating Hormone / Q000097:blood; D005832:Genital Diseases, Male / Q000175:diagnosis / Q000503:physiopathology; D007987:Gonadotropin-Releasing Hormone / Q000097:blood; D006801:Humans; D007006:Hypogonadism / Q000175:diagnosis / Q000503:physiopathology; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D011628:Puberty, Delayed / Q000175:diagnosis / Q000503:physiopathology; D013733:Testicular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D013739:Testosterone / Q000097:blood*; D014646:Varicocele / Q000175:diagnosis
D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone