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Background Clinically non-functioning Pituitary Adenomas (NFPA) are among the most common neoplasms of the sellar region. They usually present with compressive symptoms such as headache and visual field defects and not infrequently, are found incidentally. NFPA are classified as gonadotropinomas, null cell adenomas, according to their immunohistochemical phenotype. The molecular alterations responsible for the development of these lesions are incompletely understood, and there is scarce information regarding the molecular alterations and markers. Objective We carried out an in-silico analysis aimed at identifying the molecular alterations in NFPA and to discover new molecular markers. Methods Twenty-three microarray libraries were analyzed. Fourteen correspond to NFPA and 9 to control tissue gland. They were analyzed using Partek Genomic Suite to identify differentially expressed genes and WebGestalt and Metascape to understand the meaning behind the gene lists. Results Pituitary adenomas showed a markedly different transcriptome compared to the non-tumoral gland, regardless of their putative immunophenotype. Genes related to calcium metabolism such as CACNA2D4, immune-related CXCR4, and stem cell-related KLF8 and PITX2 were altered. Conclusions Differentially expressed calcium metabolism and immune-related genes in NFPA represent attractive molecular markers and potential therapeutic targets.

Gonadotropin-releasing hormone (GnRH) is the primary neuropeptide controlling reproduction in vertebrates. GnRH stimulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis via a G protein-coupled receptor, GnRHR, in the pituitary gland. In mammals, GnRHR lacks a C-terminal cytosolic tail (Ctail) and does not exhibit homologous desensitization. This might be an evolutionary adaptation that enables LH surge generation and ovulation. To test this idea, we fused the chicken GnRHR Ctail to the endogenous murine GnRHR in a transgenic model. The LH surge was blunted, but not blocked in these mice. In contrast, they showed reductions in FSH production, ovarian follicle development, and fertility. Addition of the Ctail altered the nature of agonist-induced calcium signaling required for normal FSH production. The loss of the GnRHR Ctail during mammalian evolution is unlikely to have conferred a selective advantage by enabling the LH surge. The adaptive significance of this specialization remains to be determined.

The pituitary is a master endocrine gland that developed early in vertebrate evolution and therefore exists in all modern vertebrate classes. The last decade has transformed our view of this key organ. Traditionally, the pituitary has been viewed as a randomly organized collection of cells that respond to hypothalamic stimuli by secreting their content. However, recent studies have established that pituitary cells are organized in tightly wired large-scale networks that communicate with each other in both homo and heterotypic manners, allowing the gland to quickly adapt to changing physiological demands. These networks functionally decode and integrate the hypothalamic and systemic stimuli and serve to optimize the pituitary output into the generation of physiologically meaningful hormone pulses. The development of 3D imaging methods and transgenic models have allowed us to expand the research of functional pituitary networks into several vertebrate classes. Here we review the establishment of pituitary cell networks throughout vertebrate evolution and highlight the main perspectives and future directions needed to decipher the way by which pituitary networks serve to generate hormone pulses in vertebrates.