  Synergistic Control by Androgens and Estrogens of Aromatase in the Quail BrainBalthazart, Jacques  ; ; Foidart, Agnès et alin Neuroreport (1994), 5(14), 1729-32 Castrated quail were injected with testosterone or with the synthetic hormones diethylstilbestrol (DES) or methyltrienolone (R1881) to analyse the steroid specificity in the induction of brain aromatase ... [more ▼] Castrated quail were injected with testosterone or with the synthetic hormones diethylstilbestrol (DES) or methyltrienolone (R1881) to analyse the steroid specificity in the induction of brain aromatase. R1881 produced a moderate (generally non-significant) increase in the number of aromatase-immunoreactive cells. DES significantly increased the number of positive cells in most brain areas. A clear synergism between DES and R1881 was observed in all brain regions: more immunoreactive cells were found in birds receiving both compounds than in those injected with DES or R1881 alone. DES and R1881 are highly specific ligands for oestrogen and androgen receptors respectively. It appears likely that both androgens and oestrogens directly modulate brain aromatase, presumably at the transcription level. [less ▲] Detailed reference viewed: 4 (0 ULg) Distribution and Regulation of Estrogen-2-Hydroxylase in the Quail BrainBalthazart, Jacques ; ; Foidart, Agnès et alin Brain Research Bulletin (1994), 35(4), 339-45 The anatomical distribution and endocrine regulation of the estrogen-2-hydroxylase activity were investigated in the brain of adult male and female Japanese quail. Significant levels of enzymatic activity ... [more ▼] The anatomical distribution and endocrine regulation of the estrogen-2-hydroxylase activity were investigated in the brain of adult male and female Japanese quail. Significant levels of enzymatic activity were detected in all brain regions that were studied, but the highest levels were observed in preoptic and hypothalamic brain nuclei that are known to contain high levels of aromatase activity. These data are consistent with previous results suggesting that the placental aromatase is also responsible for the estrogen-2-hydroxylase activity. However, there is a marked sex difference and a control by T of aromatase activity in the quail brain, and no such difference in 2-hydroxylase activity could generally be detected except in the VMN. Further studies will be needed to know whether the previously published conclusions concerning the human placenta also apply to the brain. The present data are consistent with the idea that estrogens formed locally in the brain by testosterone aromatization could affect reproduction by interfering with the catecholaminergic transmission after being metabolized into catechol-estrogens. [less ▲] Detailed reference viewed: 11 (0 ULg) |
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