The differential diagnosis between hypogonadotropic hypogonadism and delayed puberty is facilitated by comparing the response of gonadotropins to LH-RH stimulation before and after administration of clomiphene citrate 200 mg daily during 7 days. Premedication of clomiphene citrate depresses peak values of LH and FSH on LH-RH in delayed puberty. In hypogonadotropic hypogonadism clomiphene citrate raises LH-RH induced peak LH while FSH does not change.

LH-RH injection and infusion studies were performed in advanced puberty, delayed puberty and hypogonadotrophic hypogonadism. No differential diagnosis could be made between delayed puberty and hypogonadotrophic hypogonadism using LH-RH injection. In the LH-RH infusion studies evidence was obtained that stimulation of the pituitary during 4 h results in continuously rising LH levels in advanced puberty and in delayed puberty while in hypogonadotrophic hypogonadism the secretory capacity of the pituitary is gradually exhausted. This phenomenon can be used in the differential diagnosis between delayed puberty and hypogonadotrophic hypogonadism. Though the FSH data point in the same direction they are not useful in this connection as the overlap between the different categories was considerable.It is still difficult to distinguish between physiological delayed puberty (DP) and hypogonadotrophic hypogonadism (HH). Studies of pituitary function with LH-RH and clomiphene citrate did not answer this question nor did studies of testicular testosterone production following hCG stimulation (Bardin et al. 1969;Kulin et al. 1969; Roth et al. 1972). A prospective differential diagnosis is possible comparing the results of two LH-RH injection tests before and after administration of clomiphene citrate (Snoep et al. 1977). In DP LH-RH stimu¬ lated LH levels are lower in the second test while in HH the values are higher. There are several possible explanations for this phenomenon, at present all

Eight boys with severely delayed puberty without pathological cause were treated for 6 months with testosterone. This resulted in acceleration of skeletal maturation and a marked increase in height and weight. No adverse effects were found on hypothalamic-pituitary and gonadal maturation. Basal LH, FSH and testosterone levels rose to nearly adult values at follow-up within a year and pituitary responsiveness to LH-RH increased markedly.Until recently a definite diagnosis of delayed puberty in boys could be made only in retrospect. As idiopathic delayed puberty cannot easily be separated from other causes of male hypogonadism, this makes evaluation of therapy difficult. The social and psychological disadvantages incurred by boys with retarded puberty sometimes necessitate institution of hormone therapy. It is still uncertain whether such therapy has an overall beneficial effect. Androgens promote both a rapid pubertal growth and epiphyseal closure. The latter may influence final stature adversely. A retrospective study has shown that treatment with low doses of androgens during a mean period of 5.3 months does not impair the final height attained and possibly even promotes growth (Kaplan et al. 1973). No data are available concerning the influence of this treatment on later fertility. Following administration of testosterone in high doses for 1 year to boys with excessive height, spermatogenesis recovered after

The diagnosis of idiopathic delayed pubertal development in boys is difficult. A single GnRH test does not give information concerning hypothalamic maturity. After one week clomiphene citrate administration the LH reaction pattern is enhanced in subjects with maturing and depressed in subjects with immature hypothalamic-pituitary function.