Biosynthesis and secretion of steroids by the canine testis

Molen, H. J. van der; Eik‐Nes, Kristen B.

doi:10.1016/0005-2760(71)90023-3

Cited by 21 publications

(3 citation statements)

References 37 publications

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“…If free an-a and an-fl were formed only from 5aandrost-16-en-3-one, and if only one pool of these androstenols existed in the testis, the specific radioactivities of all three compounds should be the same. Similar findings have been reported from experiments in which canine testes were infused with labelled pregnenolone (van der Molen & Eik-Nes, 1971). Further, Bell et al (1971) showed that, although testosterone was synthesized mainly in the Leydig cells of rat testicular preparations, there was also some synthesis in the seminiferous tubules.…”

Section: Discussionsupporting

confidence: 71%

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

Saat

Gower

Harrison

et al. 1974

Biochemical Journal

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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.

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Section: Discussionsupporting

confidence: 71%

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

Saat

Gower

Harrison

et al. 1974

Biochemical Journal

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“…Since the gland has come to an apparent steady state condition with regard to 3H-T utilization in these experiments (table V), our data suggest that the infused prostate, like the infused dog testis [40], could have 'storage' pools and 'secretory' pools for T of different sizes. With regard to DHT specific radioactivity in tissue and venous blood of prostates and testes infused with 3H-T via the arteries (table VI, IX), these discrepancies are smaller than those for T (table V, VI, IX).…”

Section: Discussionmentioning

confidence: 68%

Production and Secretion of 5α-Dihydrotestosterone by Male Reproductive Organs

Eik‐Nes¹

1971

Gynecol Obstet Invest

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The androgen 5Α-dihydrotestosterone (DHT) has been isolated and identified in testicular tissue (rats, dogs) and in testicular venous blood of the canine testis. Conversion of ³H-testosterone (T) to ³H-DHT in vitro by testicular tissue from rats treated with follicle-stimulating hormone in vivo tended to increase. No such effect of human chorionic gonadotropin treatment could be observed. The Leydig cells of testes from mature rats contribute little to the formation in vitro of ³H-DHT from ³H-T. Both these androgens can be found in spermatic lymph and in epididymal tissue of the dog. In an isolated prostate preparation where the gland is infused via the prostatic arteries with the animal’s arterial blood at a constant rate, DHT can be found in effluent blood. The dog prostate both produces and secretes DHT. The purpose of DHT production and secretion by male reproductive organs is discussed.

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“…However, some androgen biosynthesis occurs in the seminiferous tubules of rat (Christensen & Mason, 1965) and rabbit (Collins, 1968) testes. Recent experiments, in which canine testes were infused with [4-14C]pregnenolone (van der Molen & Eik-Nes, 1971), also indicate more than one compartment for androgen synthesis, since the specific radioactivities of metabolites in the testis were not equal to those of corresponding metabolites in the spermatic venous plasma.…”

Section: Identification Of 16-unsaturated C1 Steroids In Spermatic Vmentioning

confidence: 99%

Studies on the biosynthesis in vivo and excretion of 16-unsaturated C19 steroids in the boar

Saat

Gower

Harrison

et al. 1972

Biochemical Journal

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1. In one experiment [7alpha-(3)H]pregnenolone was infused continuously for 12min into the left spermatic artery of a sexually mature boar and blood was collected during this period by continuous drainage from the spermatic vein. After infusion, the testis was removed and immediately cooled to -196 degrees C. 2. From both the testicular tissue and the spermatic venous plasma, (3)H-labelled 16-unsaturated C(19) steroids were isolated and characterized and their radiochemical purity was established. 5alpha-Androst-16-en-3alpha- and 3beta-ol occurred mainly as sulphate conjugates and to a lesser extent as free steroids. Only traces of these alcohols occurred as glucosiduronate conjugates. 5alpha-Androst-16-en-3-one was found in the free (ether-extractable) fraction. 3. The isotope concentration of each of the (3)H-labelled 16-unsaturated C(19) steroids in testicular tissue was different from that in spermatic venous plasma. 4. The ratios of tritiated 5alpha-androst-16-en-3alpha- and 3beta-ol (free steroids) to their respective sulphate conjugates in the testicular tissue were less than the ratios of the same compounds in the spermatic venous plasma. The possibility that the sulphates are partially hydrolysed by testicular sulphatases before secretion is discussed. 5. In a second experiment, a continuous close-arterial infusion of [7alpha-(3)H]pregnenolone into the left testis was performed over a 200min period and all the urine that accumulated during the infusion was collected for analysis. 6. No (3)H-labelled 16-unsaturated C(19) steroids were detected in the urine as free steroids. Only a trace of 5alpha-androst-16-en-3alpha-ol was detected conjugated as glucosiduronate, whereas the corresponding 3beta-alcohol occurred mainly as glucosiduronate and to a lesser extent as sulphate. 7. The absence of 5alpha-androst-16-en-3beta-ol glucosiduronate in the spermatic venous blood and its presence in considerable amount in the urine may be attributed to hepatic glucuronyl transferase activity.

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Biosynthesis and secretion of steroids by the canine testis

Cited by 21 publications

References 37 publications

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

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

Production and Secretion of 5α-Dihydrotestosterone by Male Reproductive Organs

Studies on the biosynthesis in vivo and excretion of 16-unsaturated C19 steroids in the boar

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