Figure 2: Mass-spectrometric analysis of hippocampal sex-steroids (12-week-old female rats), LC-MS/MS ion chromatograms of T (A), DHT(B) and Allo(C). (A1), (B1) and (C1) represent the chromatograms of the fragmented ions of each steroid from the hippocampus. Shaded portions indicate the intensity of fragmented ions of T (m/z=253), DHT (m/z=203) and Allo (m/z=283.3), respectively. (A2), (B2) and (C2) represent the chromatograms of the fragmented ions of the standard steroids. The vertical axis indicates the intensity of the fragmented ion. The horizontal axis indicates the retention time of the fragmented ion, t=4.12 min for T, 4.37 min for DHT, and 8.43 min for Allo, respectively. The time of sample injection to LC system was defined as t=0 min. Note that pre-purification step using normal phase HPLC before injection to LC system is very important to achieve high precision and good reproducibility of LC-MS/MS determination in order to avoid contamination of other steroids and fats. Steroid-derivatives or steroids were further separated with reversed phase LC-column before MS/MS. In the multiple reaction monitoring modes, the instrument monitored the m/z transition (Table S2).