Abstract: Purpose: To understand the differences in steroid hormone contents between goat and cow milk at different lactation stages. Methods: The contents of steroid hormones in goat and cow milk at different lactation stages were investigated using ultra-high liquid chromatography-mass spectrometry (UPLC-MS). Gradient elution was performed using 0.5 mmol/L ammonium fluoride aqueous solution as mobile phase A and methanol as mobile phase B at a flow rate of 0.3 mL/min, and the target analytes were qualitatively and quantitatively detected using an electrospray ionization (ESI) source in the multiple reactions monitoring (MRM) mode. Results: A total of 11 steroid hormones, 17α-hydroxyprogesterone, 17α-pregnenolone, epi-testosterone, pregnenolone, progesterone, androstenedione, testosterone, estradiol, estrogen, cortisol, and cortisone, were detected from goat and cow milk samples. At the early lactation stage, the contents of 17α-hydroxyprogesterone, estrogen and cortisol showed significant differences between goat and cow milk (P < 0.05), and the contents of progesterone and progesterone showed extremely significant differences (P < 0.01); at the full lactation stage, significant differences in the contents 17α-hydroxyprogesterone, 17α-pregnenolone, androstenedione, and cortisone (P < 0.05), and extremely significant differences in the contents of progesterone and pregnenolone were found (P < 0.01); at the late lactation stage, significant differences in the contents of 17α-hydroxyprogesterone, androstenedione, estrogen, and cortisol (P < 0.05) were observed as well as extremely significant differences in the content of 17α-hydroxypregnenolone, pregnenolone, and progesterone (P < 0.01). Conclusion: The differences in steroid hormone contents between goat and cow milk may be due to different pregnancy status.

Key words: ultra-high liquid chromatography-tandem mass spectrometry; goat milk; cow milk; lactation period; steroid hormones; content differences

摘要： 目的：了解不同泌乳期山羊乳与牛乳中类固醇激素含量差异。方法：采用超高效液相色谱-串联质谱方法, 分析不同泌乳期山羊乳和牛乳中类固醇激素含量。以0.5 mmol/L氟化铵溶液和甲醇作为流动相进行梯度洗脱, 采用电喷雾离子化质谱的多反应监测模式对目标分析物进行定性和定量检测。结果：山羊乳与牛乳样品中共检出11 种类固醇激素, 分别为17α-羟基孕烯醇酮、17α-羟基孕酮、表睾酮、孕烯醇酮、孕酮、雄烯二酮、睾酮、雌二醇、雌激素、皮质醇和可的松, 其中, 泌乳初期山羊乳与牛乳相比, 17α-羟基孕烯醇酮、雌激素、皮质醇含量差异显著（P＜0.05）, 孕酮、孕烯醇酮含量差异极显著（P＜0.01）；泌乳盛期17α-羟基孕烯醇酮、17α-羟基孕酮、雄烯二酮、可的松含量差异显著（P＜0.05）, 孕酮、孕烯醇酮含量差异极显著（P＜0.01）；泌乳末期17α-羟基孕酮、雄烯二酮、雌激素、皮质醇含量差异显著（P＜0.05）, 17α-羟基孕烯醇酮、孕烯醇酮、孕酮含量差异极显著（P＜0.01）。结论：山羊乳与牛乳中类固醇激素含量的差异可能是由于妊娠状态不同导致。

关键词: 超高效液相色谱-串联质谱；山羊乳；牛乳；泌乳期；类固醇激素；含量差异