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Updated: May 21, 2026
Two-dimensional Gel Electrophoresis Coupled with Mass Spectrometry Methods for an Analysis of Human Pituitary Adenoma Tissue Proteome
Published on: April 2, 2018
Quantitative analysis and clinical evaluation of 20- and 22-kDa growth hormone isoforms in somatotroph adenoma using
Yao Hu1, Yanwen Chen1, Qiuyi Xia1
1Department of Laboratory Medicine,Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
Objectives:
The 20- and 22-kDa isoforms of growth hormone 1 (GH1) play potentially distinct physiological and pathological roles, but their structural similarity makes quantification challenging. Conventional immunoassays lack sufficient specificity, highlighting the need for more precise analytical methods.
Methods:
We developed a method combining immunocapture with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for precise quantification of GH1 isoforms, with evaluation of sensitivity, accuracy, precision, and linearity. GH1 was isolated from 1-mL serum samples by immunocapture using antibody-coated magnetic beads, eluted, and quantified by LC-MS/MS. Stable isotope-labeled 22-kDa GH1 was used as an internal standard (IS). Clinical applicability was evaluated by analyzing serum GH1 isoforms in 63 patients with somatotroph adenoma.
Results:
The assay demonstrated linear dynamic ranges of 0.2-20.0 μg/L for 20-kDa GH1 and 1.0-100.0 μg/L for 22-kDa GH1. Intra- and inter-assay coefficients of variation were <10 %, and recoveries ranged from 95.0 to 102.5 % after IS correction. Although total GH1 concentrations measured by LC-MS/MS were systematically lower than those obtained by immunoassay, the two methods were strongly correlated (r=0.991, p<0.01). Most patients with somatotroph adenoma (80.0 %; 51/63) exhibited increased 22/20-kDa GH1 ratios, while six patients with unfavorable clinical features and endocrine prognosis exhibited elevated 20-kDa GH1 levels.
Conclusions:
This immunocapture LC-MS/MS method enables simultaneous quantification of 20- and 22-kDa GH1 isoforms without enzymatic digestion. The implementation of this method may refine the assessment of biochemical remission and prognostic stratification in GH-related disorders.
