Testosterone Metabolism by Gastrointestinal Microsomes

Abstract

HARRI, M.-P., K. HARTIALA, W. NIENSTEDT and H. A. SALMI. Testosterone metabolism by gastrointestinal microsonirs. Acta physiol. scand. 1970. 79. 537-540. I n incubation studies with the microsonial fraction of various tissues of the rat, the ability to metabolize testosterone, determined as the decrease in N.4DPHz absorbance, was found to he rather high in various gastrointestinal tissues but lower in several non-gastrointestinal tissues. I n one case, some of the numerous metabolites were identified with hepatic-, ileal mucosal and heart tissues. All of them apparently produce a t least 4-androstenedione, 5a-androstanedione, and 1 7,"-hydroxy-5u-androstan-3-one.

Comparison of the Metabolism of Testosterone Undecanoate and Testosterone in the Gastrointestinal Wall of the Rat in Vitro and in Vivo

“…In in vivo studies in rats it was shown that the greater part of the orally administered TU was metabolized in the intestinal wall . This is in accordance with the results of Harri et al (1970Harri et al ( , 1972 who demonstrated the metabolism of testosterone and androstenedione in the intestinal wall of the dog. In the present study the metabolism of TU as well as of T in the gastrointestinal wall of the rat was studied in vitro and compared with the results obtained in vivo.…”

Treatment of anorchia with oral testosterone undecanoate: pharmacodynamics and clinical effectiveness

“…The oral administration of genuine T is rather ineffective due to the rapid metabolism of the hormone both in the liver and in the intestinal wall (Foss & Camb 1939;Harri et al 1970). Recenüy, however, Johnsen et al (1974) have shown that 200 mg of oral T can produce normal male serum T levels for 5-7 h in eunuchs and therefore might be a useful form of androgen therapy (Johnsen 1978).…”

Separation of oestrone UDP-glucuronyltransferase and p-nitrophenol UDP-glucuronyltransferase activities

“…Hepatic microsomal UDP-glucuronosyltransferase (EC 2.4.1.17) catalyses the conjugation of UDPglucuronic acid with numerous classes of chemicals, such as carboxylic acids (Dutton, 1956), amines (Arias, 1961), thiol derivatives (Dutton & Illing, 1972), bilirubin (Schmid et al, 1957;Lathe & Walker, 1958) and certain hormones (Harri et al, 1970;Miller et al,-1973;Fuchs et al, 1977). Since such a broad spectrum of substrates is glucuronidated, numerous studies have suggested a multiplicity of glucuronyltransferases (Dutton & Burchell, 1977).…”