University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh , 47 Little France Crescent, Edinburgh, EH16 4TJ, United Kingdom.
Centre for Integrative Physiology, University of Edinburgh , Hugh Robson Building, 15 George Square, Edinburgh EH8 9XD, United Kingdom.
Anal Chem. 2016 Nov 1;88(21):10362-10367. doi: 10.1021/acs.analchem.6b02242. Epub 2016 Oct 14.
Androgens are essential for male development and reproductive function. They are transported to their site of action as blood-borne endocrine hormones but can also be produced within tissues to act in intracrine and paracrine fashions. Because of this, circulating concentrations may not accurately reflect the androgenic influence within specific tissue microenvironments. Mass spectrometry imaging permits regional analysis of small molecular species directly from tissue surfaces. However, due to poor ionization and localized ion suppression, steroid hormones are difficult to detect. Here, derivatization with Girard T reagent was used to charge-tag testosterone and 5α-dihydrotestosterone allowing direct detection of these steroids in mouse testes, in both basal and maximally stimulated states, and in rat prostate. Limits of detection were ∼0.1 pg for testosterone. Exemplary detection of endogenous steroids was achieved by matrix-assisted laser desorption ionization and either Fourier transform ion cyclotron resonance detection (at 150 μm spatial resolution) or quadrupole-time-of-flight detection (at 50 μm spatial resolution). Structural confirmation was achieved by collision induced fragmentation following liquid extraction surface analysis and electrospray ionization. This application broadens the scope for derivatization strategies on tissue surfaces to elucidate local endocrine signaling in health and disease.
雄激素对于男性的发育和生殖功能至关重要。它们作为血源性内分泌激素被运输到作用部位，但也可以在组织内产生，以发挥自分泌和旁分泌作用。正因为如此，循环浓度可能无法准确反映特定组织微环境中的雄激素影响。质谱成像允许直接从组织表面对小分子物质进行区域分析。然而，由于电离不良和局部离子抑制，类固醇激素很难被检测到。在这里，使用 Girard T 试剂对睾酮和 5α-二氢睾酮进行衍生化，从而可以直接检测到处于基础和最大刺激状态的小鼠睾丸以及大鼠前列腺中的这些类固醇。睾酮的检测限约为 0.1 pg。通过基质辅助激光解吸电离，并采用傅里叶变换离子回旋共振检测（在 150 μm 空间分辨率下）或四极杆-飞行时间检测（在 50 μm 空间分辨率下）实现了内源性类固醇的示例检测。通过液体提取表面分析和电喷雾电离后的碰撞诱导碎片化实现了结构确证。该应用拓宽了组织表面衍生化策略的范围，以阐明健康和疾病中的局部内分泌信号。
