Studies on the metabolism of 5α-androst-16-en-3-one in boar testis in vivo

Abstract

1. [5alpha-(3)H]5alpha-Androst-16-en-3-one (5alpha-androstenone) was infused at a constant rate for 180min into the spermatic artery of a sexually mature boar. Samples of spermatic-venous blood were collected at 1min intervals for the first 10min of the infusion and thereafter at 15min intervals for the first hour, then at 64, 125, 155 and 172min. After infusion, the testis was removed and immediately cooled to -196 degrees C. 2. From both the testicular tissue and the spermatic-venous plasma, endogenous and (3)H-labelled androst-16-enes were isolated, characterized and quantitatively determined and their specific radioactivity was calculated. 3. The specific radioactivities of 5alpha-androstenore, 5alpha-androst-16-en-3alpha-ol and 5alpha-androst-16-en-3beta-ol (an-alpha and an-beta) in testicular tissue were different from those in the spermatic-venous plasma, suggesting that these compounds may be present in more than one compartment of the testis and differentially secreted into the spermatic-venous blood. 4. The ratios of the specific radioactivities of an-alpha and an-beta to their respective sulphate conjugates in the testicular tissue were less than the ratios of the same compounds in the spermatic-venous plasma. 5. The patterns of secretion of these labelled compounds in the spermatic-venous blood during the period of infusion were demonstrated. 6. The urine that accumulated during the infusion was analysed and found to contain (3)H-labelled an-beta, conjugated as both glucuronide and sulphate, the specific radioactivities of which were determined. Little or no androst-16-enes occurred as free steroids. 7. The presence of an-beta glucuronide in the urine is discussed.

Biochemical, nutritional and genetic effects on boar taint in entire male pigs

“…Androstenone is metabolised to 5a-androst-16-en-3a-ol (3a-androstenol) and 5a-androst- 16-en-3b-ol (3b-androstenol), as demonstrated by in vitro (Brophy and Gower, 1972;Sinclair et al, 2005a) and in vivo studies (Saat et al, 1974). The androstenols are subsequently metabolised to produce more polar conjugated steroids (Sinclair and Squires, 2005).…”

A note on the metabolism of 5α-androst-16-en-3-one in the young boar in vivo

“…However, the quantitative importance of these polar compounds appears to be an original result since they are the main form of androstenone elimination in the young boar. Previous results obtained in the mature boar (Gower et al, 1970Saat et al, 1974) Only 51 % of the injected radioactivity was recovered in urine after one week of collection, whereas a small proportion was eliminated in the faeces. The remaining radioactivity was probably still stored in body tissues since the apparent half-life of fat androstenone is in the range of 4 to 14 days in boars of similar age and weight (Claus, 1976 ;Bonneau et al, 1982 …”

“…The presence of metabolites other than an-a or an-0 have been previously established in boar plasma (Saat et al, 1974) and human urine (Kingsbury and Brooksbank, 1978). However, the quantitative importance of these polar compounds appears to be an original result since they are the main form of androstenone elimination in the young boar.…”

“…Indeed, few experiments have been devoted to the mechanisms by which circulating androstenone is stored in fatty tissue or to the pathways and intensity of its catabolism. In the mature boar, C 19 < l 16 steroids are probably catabolized in the liver (Claus, 1979 ;Fish et a/., 1980) and subsequently eliminated in the uterine, mainly in the form of an-!i glucuronide (Gower et al, 1970 a, b ;Saat et al, 1972Saat et al, , 1974. The purpose of ('&dquo;) Abbreviations and trivial names : an-a : 5a-androst- 16-en-3a-ol ; an-0 : 5u-androst-16-en-30-ol ; androstenone : 5a-androst-16-en-3-one ; pregnenolone : 5-pregnen-3(3-0l-20-one ; progesterone : 4-pregnen-3, 20-dione ; ( 3 H) androstenone : (5u-3 H) 5a-androst-16-ene-3-one. this experiment was to study the metabolism and excretion of circulating androstenone in the young boar weighing about 100 kg (common slaughter weight).…”

“…Direct excretion into urine being excluded (Gower et al, 1970Saat et al, 1974 (Gower, 1972) and in vivo (Saat et al, 1974) studies, cannot explain its quick disappearance from the plasma since testicular blood flow (around 30 liters per day according to Saat et al, 1974) was negligible compared to metabolic clearance rate. Consequently, we must assume that the uptake and storage of androstenone by the salivary glands and fatty tissue are the main mechanisms responsible for its very quick disappearance from the plasma.…”