Wirkungen von Antiandrogenen*

Merits and considerations in the use of anti-androgen

Anandron administration (300 mg/daily) to 16 human normal genetic male volunteers (who opted for male to female gender transformation) induced clinical signs of feminisation during 8 weeks of treatment. More than 2-fold increase in blood luteinising hormone and testosterone was measured while follicle stimulating hormone remained without any change in the levels. Prolactin showed a slight but significant increase at 8 weeks of treatment. The prostate size measured in 6 subjects using transrectal ultrasonography before and at 8 weeks of anandron treatment showed no change. The prostate size measured in 6 subjects who received androcur (100 mg/daily) in combination with ethinyl estradiol (100 micrograms/daily) for longer than 18 months did not differ compared to pre-treatment size. However, the prostate histology showed a clear predominance of stromal components with a significant reduction in the number of acini. The epithelial cells appeared atrophic. Histology of the testes showed a readily observable reduction in tubular and interstitial cells. The monodispersed cells prepared from the testes consisted of Leydig and non-Leydig cells. These cells responded to stimuli (hCG and Pregnenolone) in terms of an increase in testosterone synthesis in vitro. Anandron treatment of intact mature male rats increased the blood testosterone level. Estrogen administration dramatically reduced the anandron induced increase in testosterone to castration level. The benefits of a combination of low doses of anandron and estrogen for achieving an effective anti-androgenic action are presented.

Toxicology of cimetidine

Cimetidine has been shown to have low acute toxicity in dogs and rodents. Repeated-dose studies of up to 24 months' duration in rodents at doses up to 950 mg day-1 kg-1 showed few adverse effects. Liver weight was consistently increased at the highest dose and testis, prostate and seminal vesicle weights were reduced in a dose- and time-related fashion. Cimetidine was not carcinogenic in the rat. In tests of up to 1 year's duration in dogs two animals receiving 504 mg day-1 kg-1 had to be killed before the end of the study. They had degenerative changes in the liver and renal tubular nephrosis. These and other dogs at 504 mg day-1 kg-1 had elevated serum transaminases. No such changes were seen at 366 mg day-1 kg-1 or less. Prostate weights were reduced in a dose- and time-related fashion. In a 7-year study in dogs, specifically designed for the purpose, no changes of the stomach mucosa were seen during regular biopsy. Although shown to be a mild anti-androgen, cimetidine produced no significant adverse effects in reproductive studies. The large body of evidence that cimetidine is not a risk for gastric cancer is reviewed. Over 30 million patients have so far been treated with cimetidine and the prediction from the animal studies that it would be an extremely safe therapeutic agent has been borne out in practice.