The human pituitary proteome: the characterization of differentially expressed proteins in an adenoma compared to a control.

In order to clarify the basic molecular mechanisms that participate in the formation of human pituitary macroadenomas, this study, for the first time, describes the comparative proteomics between a pituitary adenoma tissue and a control tissue. A vertical, two-dimensional polyacrylamide gel electrophoresis system and PDQuest image analysis software were used to provide a high level of between-gel reproducibility and electrophoretic separation to accurately locate each differentially expressed protein. Mass spectrometry (MALDI-TOF and LC-ESI-Q-IT) and protein databases were used to characterize each differentially expressed protein. A total of 137 differential gel spots (37 increased spot volumes, 39 decreased, 19 new and 42 lost) were found when we compared an adenoma proteome to a control proteome. Seventy-one spots (20 increased, 27 decreased, 13 new, 11 lost), representing 39 differentially regulated proteins, were identified. Five differentially regulated proteins (prolactin, cellular retinoic acid-binding protein II, G-protein beta subunit 3, secretagogin and calreticulin) were also validated with results from a comparative transcriptomics study of pituitary adenomas and controls. The functional characteristics of these differentially expressed proteins provide a differential proteomic profile between a pituitary adenoma and a control.