Serum-testosterone during oral administration of testosterone in hypogonadal men and transsexual women

The use and misuse of androgens

Because testosterone is rapidly metabolized by the liver, it is necessary either to administer androgens by injection in the form of testosterone esters that are absorbed slowly into the circulation or to administer by mouth derivatives that are slowly metabolized by the liver. The later derivatives, however, have deleterious side effects that limit their usefulness. Long-acting parenteral androgen esters are the treatment of choice in the replacement therapy of male hypogonadism. Because these esters must be hydrolyzed to the free hormone prior to exerting their cellular actions the effectiveness of therapy can be monitored by following plasma testosterone levels. All known effects of the endogenous hormone can be duplicated except for the induction and maintenance of normal spermatogenesis. Androgens have been tried in a variety of clinical situations other than male hypogonadism in the hopes that the nonvirilizing actions would outweigh any detectable side effects. The only disorders in which a salutary effect has been documented are hereditary angioneurotic edema and some patients with anemia due to failure off the bone marrow.

Oral levo-norgestrel - testosterone effects on spermatogenesis, hormone levels, coagulation factors and lipoproteins in normal men

Four healthy men volunteered to be treated for eight to nine months with daily oral levo-norgestrel (250 micrograms) and oral testosterone (200-600 mg) as a possible contraceptive. This was followed by a recovery phase of 5-10 months. The oral steroid combination significantly decreased sperm count in 3 of 4 subjects, and significantly increased abnormal spermatozoa, serum LH was decreased during treatment but serum FSH remained constant, except for one volunteer. Serum testosterone was decreased except for 2 daily peaks associated with the oral testosterone. During the recovery period, sperm counts and morphology, serum testosterone and serum LH returned to normal, whereas serum FSH levels were increased. Platelet aggregability induced by ADP, increased in 3 volunteers during treatment as did fibrinolytic activity and fibrinolytic capacity (2 of 3 subjects). There was a reduction in the hepatic triglyceride lipase activity but no change was seen in serum triglycerides, serum cholesterol, serum LDL, serum HDL, peripheral lipoprotein lipase activity and the intravenous fat tolerance test. No other toxicological side effects were seen.

Bioavailability of oral testosterone in males

Twenty-six male volunteers received a single oral dose of testosterone as free crystals or as the undecanoate ester. The latter was given either in crystalline form or in arachis oil. All preparations were tested three times in the same individual, whilst fasting on 2 days and on one day together with a breakfast rich in fat. Serum testosterone concentration was measured at intervals for up to 6--24 h after the dose. A significant and reproducible rise in serum testosterone level was found after ingestion of free testosterone. Testosterone esterified with undecylenic acid was only effective when administered in arachis oil. The meal increased the bioavailability of the ester, but had hardly any effect on that of the free hormone. It is concluded that bioavailability of oral testosterone can be improved by pharmaceutical means to an extent sufficient to produce adequate blood levels in substitution therapy.