β estradiol

Liquid chromatography‒mass spectrometry (LC/MS)-grade acetonitrile was obtained from Fisher (Thermo Fisher Scientific, Waltham, MA, USA). Purified water was purchased from Wahaha (Hangzhou, China). Ammonium acetate, ammonium formate, diethyl ether and hydroxypropyl-β-cyclodextrin were purchased from Sinopharm (Beijing, China). Acetic acid was obtained from TEDIA (Fairfield, USA). Formic acid was provided by Millipore (Merck, Burlington, MA, USA), and 0.9% NaCl was obtained from CSPC (Shijiazhuang, China). Histamine, γ-aminobutyric acid (GABA), 1-methyhistamine, decynium 22, S-adenosyl-l-methionine, and semicarbazide (SCZ) were purchased from Sigma–Aldrich (St. Louis, MO, USA). Histamine-α,α,β,β-d₄·2HCl was purchased from CDN isotopes (Quebec, Canada). [U–¹³C]glucose and isotopic histidine (Ring-2-¹³ (link)C) were obtained from Cambridge Isotope Laboratories, Inc. (MA, USA). 4-Aminobutyric-2,2-d₂ acid (GABA-d₂) was purchased from ZZBIO Co., Ltd. (Shanghai, China). Corticosterone, β-estradiol, 2-amino-2-norbornanecarboxylic acid (BCH), and amodiaquine dihydrochloride were purchased from MedChemExpress (Shanghai, China). YZG-331 was kindly provided by Professor Jiangong Shi (Institute of Materia Medica, Chinese Academy of Medical Sciences (CAMS), Beijing, China).