Clinicians and clinical investigators have developed improved means for controlling testicular function in men. New and refined approaches for stimulation and inhibition of the hypothalamic-pituitary-testicular axis are now available. This chapter reviewed the most successful ways to inhibit the reproductive axis in men and its current application to the treatment of
precocious puberty, metastatic
prostate cancer, benign prostate
hyperplasia and as prospective
male contraceptives. Safe, effective and reversible medical approaches to
male contraception are now approaching reality.
Azoospermia and severe oligozoo/
azoospermia can now be accomplished in the majority of men with combined
GnRH antagonists and replacement doses of
testosterone.
Androgens and
androgen-
progestogen concentrations will induce
azoospermia in over 90% of Asian men and
azoospermia or severe
oligospermia in Caucasian ethnic groups. Field trials are ongoing to determine whether
testosterone administration will be more effective than
condoms as
contraceptives. True
precocious puberty can now be managed more effectively than in the past by suppression of
gonadotropin secretion with
GnRH analogues.
Precocious puberty due to other causes can be treated more effectively with inhibitors of steroidogenesis and blockers of
androgen action. Metastatic
prostate cancer, previously treatable with either
castration or oestrogens, is now amenable to suppression of
androgen secretion.
GnRH analogues are given either alone or combined with blockers of
androgen action. While significant palliative effects are observed with endocrine ablative
therapy in most men with Stage C or D
prostate cancer, modest increases in duration of survival may be seen. Benign prostate
hyperplasia was previously approachable only with surgical intervention. Recent data have suggested that medical treatment with
5 alpha-reductase inhibitors and/or selective
alpha-adrenergic blockers may offer non-surgical alternatives in some patients. More data are needed to determine the role of medical management of this common disorder.