  Central and Peripheral Metabolism of 5 Alpha-Dihydrotestosterone in the Male Japanese Quail: Biochemical Characterization and Relationship with Reproductive Behavior; ; Balthazart, Jacques  in Brain Research (1987), 421(1-2), 105-16 An in vitro radioenzymatic assay and purification procedure by thin-layer chromatography were used to study the metabolism of dihydrotestosterone (DHT) into 3 alpha- and 3 beta-androstanediols by the ... [more ▼] An in vitro radioenzymatic assay and purification procedure by thin-layer chromatography were used to study the metabolism of dihydrotestosterone (DHT) into 3 alpha- and 3 beta-androstanediols by the brain and cloacal gland of Japanese quail. Kinetic studies showed that these 2 metabolites are produced in a linear fashion with respect to time of incubation for up to 15 min but that they continue to accumulate for up to 4 h. The maximum velocity of these reactions is high (nmol/mg protein/15 min), but the affinities of the enzymes for DHT are low (in the microM range). The enzymatic activities are not evenly distributed in the brain: they are high in the tuberal hypothalamus and lobus parolfactorius but low in the preoptic area and anterior hypothalamus. Enzyme activities are not markedly affected by treatment of the birds with either testosterone or DHT. The activity of these enzymes is lower in the preoptic area and tuberal hypothalamus of DHT-treated birds which display female-directed sexual behavior than in the same brain areas of birds which are sexually inactive. We discuss the relationships between this reductive metabolism of DHT and the activational effects of the steroid on sexual behavior. [less ▲] Detailed reference viewed: 5 (1 ULg)Effect of the injection solvent on steroid activity.; Balthazart, Jacques in General and Comparative Endocrinology (1987), 65(2), 199-202 The effects of testosterone, 5 alpha-dihydrotestosterone, and androstenedione on cloacal gland and sternotracheal muscle growth and on luteinizing hormone plasma levels were studied in Japanese quail. The ... [more ▼] The effects of testosterone, 5 alpha-dihydrotestosterone, and androstenedione on cloacal gland and sternotracheal muscle growth and on luteinizing hormone plasma levels were studied in Japanese quail. The steroids were given to the animals in daily intramuscular injections and were dissolved either in propylene glycol or in ethanol:saline (1:1). The three steroids had significant effects on the responses which were measured, but the magnitude of this effect was clearly related to the type of vehicle in which the steroids were dissolved. Furthermore there was a significant interaction between the effects of solvents and of steroid; for example, testosterone was much less androgenic than 5 alpha-dihydrotestosterone when dissolved in propylene glycol, but both had similar effects when dissolved in ethanol:saline. The effects of the mode of administration of different steroids on a given physiological response should be taken into consideration. [less ▲] Detailed reference viewed: 4 (1 ULg)Endocrine effects of castration followed by androgen replacement and ACTH injections in the male domestic duck (Anas platyrhynchos L.).; Balthazart, Jacques ; et alin General and Comparative Endocrinology (1980), 41(1), 53-61 Detailed reference viewed: 1 (0 ULg)Diurnal variations of plasma gonadotrophins in male domestic ducks during the sexual cycle.Balthazart, Jacques ; ; in General and Comparative Endocrinology (1977), 32(4), 376-89 Detailed reference viewed: 1 (0 ULg) |
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