In order to elucidate if FSH can have testosterone like effects, samples from young, non-smoking healthy volunteers, with normal body mass index, and with pharmacologically induced gonadotropin deficiency will be studied regarding their capacity to induce prostate specific antigen (PSA), which normally is regulated by testosterone.

Normally, prostate specific antigen (PSA), which is a marker for prostate disease and progression, is exclusively produced in response to testosterone. In order to elucidate if follicle stimulating hormone (FSH) can have testosterone like effects, samples from n=30 non-smoking healthy volunteers, 20-30 years of age and with normal body mass index (20-25) with pharmacologically induced gonadotropin deficiency will be studied. The men are currently recruited and during 5 weeks undergoing:

1. Pharmacologically induced gonadotropin deficiency w 1-3;
2. FSH-treatment of 50% (group A), w 1-5;
3. Testosterone (T) treatment of all (group A and B) w 4-5;
4. End and follow up after 5 weeks.

A subcutaneous injection with the GnRH antagonist degarelix (240 mg¸ Ferring GmbH Wittland, Kiel, Germany) results in drop of both FSH and LH-induced testosterone. Half of the men will get recombinant FSH (300 IU; Gonal-f, Merck Serrono S.A. Aubonne, Schweiz) back, whereas 50% will not. Three weeks thereafter, the full spectrum of FSH dependent changes occur and are reflected in blood. From this occasion testosterone (Nebido, Ferring GmbH Wittland, Kiel, Germany) will be given to all participants to diminish the side-effects of the castration. Blood samples are collected at start, after 3 wks and after 5 wks. At that point also a follow up is undertaken. This experimental design will provide samples from each individual during normal conditions, during castration, and after a standardised dose of FSH.

Inclusion Criteria: Healthy, non-smoking, body mass index 20-25, Exclusion Criteria: Medication or drug abuse

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