Expression of the androgen receptor was also more abundant on the male side (Agate (Peer & Motz, 2014) (See also references in these articles for other examples) but gynandromorphism has not, to my knowledge, been observed in other vertebrate classes. chromosomes in birds) was expressed exclusively on the left side of the brain. Correlatively, the song control nucleus HVC was 80% larger on the male right side of the brain than on the female left side, an asymmetry that had never been observed in control zebra finches. Expression of the androgen receptor was also more abundant on the male side (Agate (Peer FGF1 & Motz, 2014) (See also references in these articles for other examples) but gynandromorphism has not, to my knowledge, been observed in other vertebrate classes. The general significance of this singularity was therefore difficult to establish even if a partial gynandromorphism can be experimentally induced by grafting parts of a chicken embryo into a chicken of the opposite sex (Clinton with DPN while males injected with PPT essentially showed a normal copulatory activity (Court activity of some of these enzymes in this widely used animal model had been well documented (Tsutsui work with radioactive T has indeed identified an active 17-HSD and an extremely high 5-reductase activity in the brain (Balthazart and in the preoptic area-hypothalamus (HPOA) of male Japanese quail after various experimental manipulations. (A) Phosphorylating conditions (addition of ATP/Mg/Ca) to HPOA homogenates inhibits AA within P276-00 15 min and this effect is blocked by the addition of EGTA, which chelates calcium or of various kinase inhibitors such as staurosporin, bisindolylmaleimide or H89 that respectively inhibit the serine/threonine kinases, phosphokinase C or phosphokinase A. (B) Rapid and reversible inhibition of AA in paired HPOA explants maintained in vitro and exposed from minute 20 to 30 to an increased concentration of potassium (K+). (C) Inhibition of AA in the medial preoptic nucleus dissected by the Palkovits punch technique from the brain of male quail that were exposed to and had the opportunity to copulate with a female for 2, 5, 10 or 15 min. (D) Rapid increase in AA in the medial preoptic nucleus dissected by the Palkovits punch technique from the brain of male or female quail that had been exposed to an acute restraint stress from minute 0 to 30. The increase was more rapid in males than in females but AA returned to baseline with 15 P276-00 min after birds were replaced in their home cage. Redrawn from data in (Balthazart studies of the HEK296 cell line transfected with aromatase demonstrating that the enzymatic inhibition induced by phosphorylating conditions (increased ATP, Mg2+ and Ca2+ concentrations) is associated with an increase of phospho-serine and an increased incorporation of 32P in the presence of 32P-ATP in the Western blot band corresponding to immunoreactive aromatase (Charlier dialysis and injection of glutamate in the preoptic area of anesthetized quail locally decreased this enzymatic activity (de Bournonville microdialysis associated with ultra-sensitive immuno-enzymo assays (Remage-Healey microdialysis could not be extrapolated to other steroids or animal models. Encouraged by this study, we decided however to test whether estradiol could similarly be measured by dialysis in the quail POA, another model system where aromatase activity is relatively high. With the help of a super sensitive RIA based on radioactive iodine we were able to demonstrate that there is within P276-00 the medial POA a transient rise in concentration of immunoreactive estradiol when males are allowed to copulate with a female. A similar rise was also observed in the bed nucleus of the stria terminalis in males that were only allowed to interact visually with a female and this increase was actually of a longer duration (de Bournonville assays in POA dissected immediately after the sexual interaction remains unclear at present. This was recently discussed in full detail (Balthazart, 2017; de Bournonville (Moore & Miller, 1984; Moore & Orchinik, 1991). In 1999, one first study on male rats demonstrated that a single injection of estradiol increases genital olfactory investigations and mounts with latencies of 20 to 30 min (Cross & Roselli, 1999). This prompted us to research in quail whether the rapid changes brain aromatase activity that we had identified had any behavioral consequences..