The effects of clomiphene citrate were studied in nine normal men, in three patients with partial panhypopituitarism, and in four patients with isolated gonadotrophin deficiency. The administration of this drug to the normal subjects in a dosage of 3 mg/kg/day for 10 days resulted in a mean rise in serum luteinizing hormone (LH) of 107 %, in plasma 17\g=b\-hydroxyandrogens (17-OHA) of 114%, and in plasma total cortisol of 86%. The rise of testosterone concentration in normal subjects was associated with a doubling of the non-protein bound fraction, and also with increased binding of testosterone to sex hormone-binding globulin (SHBG). In contrast, plasma non\x=req-\ protein bound and urinary unconjugated cortisol remained unchanged. The percentage of plasma cortisol not bound to protein fell, indicating that the rise in total plasma cortisol was secondary to increased protein binding. This was confirmed by finding increased binding of both cortisol and testosterone to their specific binding globulins at 1 \ s=deg\ C, due apparently to increased concentrations of SHBG and corticosteroid-binding globulin after clomiphene administration. All the responses to clomiphene were prevented by simultaneous administration of fluoxymesterone in two normal subjects.All the hypopituitary patients showed no rise of LH, 17-OHA or cortisol. The hypogonadotrophic patients, however, showed a normal total cortisol rise.It is suggested that clomiphene has two actions. First, it interferes with the hypothalamic feed-back mechanisms for testosterone, resulting in increased LH secretion, and secondly it has an oestrogen-like effect in stimulating production of steroid-binding globulins.

Human luteinizing hormone (LH) was given by intravenous infusion to four normal male volunteers. The disappearance of immunoreactive LH from serum followed a single exponential decay, the mean half-life being 136 min. The effect on the testis of the infused LH was variable. Despite high serum LH levels being achieved, only one subject showed a clear increase in circulating 17\g=b\-hydroxyandrogen(17-OHA) levels, the other subjects showing little change in the immediate post-infusion period. All subjects had low 17-OHA levels in the period 24\p=n-\36h after the infusion. No consistent changes in serum follicle-stimulating hormone levels occurred during or after the infusion. This suggests that other factors besides LH are necessary to produce maximal testosterone secretion by the testis, and may also be concerned in controlling the diurnal variation of testosterone.

Summary: Serum growth hormone levels were measured during insulin tolerance tests in 36 patients after yttrium-90 pituitary implantation for diabetic retinopathy.

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Serial serum assays of immunoreactive FSH before, during and after a 4 h intravenous infusion of human follicle stimulating hormone (hFSH) in five healthy men revealed two disappearance rate constants with corresponding mean half-lives of 2.9 and 50.6 h. The mean distribution spaces calculated for the fast and slow component were 4.36 I and 75.9 1 respectively. The average value for the metabolic clearance rate was 17.2 ml/min and for the 225 Acta endocr. 81, 2 là I. Kinetics of human follicle stimulating hormone