tracers to locate adrenal gland tumors through scintigraphic imaging. A similar method may be utilized to carry and more accurately administer radioactive treatments to tumors. Octreotide and other analogs are preferred for this use due to their possessing of an extended half life compared to the naturally-occurring hormone allowing for more flexibility when used for such treatments. The association of somatostatin 2 receptors on tumors has also led to the suggestion of possible alternatives to current tumor treatment methods. The binding of synthetic somatostatin hormones such as octreotide to receptors has been seen to reduce the production of hormones and is now being considered for use in the treatment of some pituitary tumors. One group suggests that the treatment method would be particularly effective against thyrotropin-secreting pituitary adenomas (TSHomas), though further inquiries and clinical trials are needed. SSTR2 is also being investigated for its potential use as a reporter gene for the visualization of regional gene expression. One study tested this by comparing the PET/CT and light imaging results of laboratory rats' musculature obtained through the use of a human somatostatin receptor 2 vector and a control luciferase vector. The study suggests that somatostatin receptor genes could be an effective substitute for the current viral-based vectors since the sstr genes elicits less of an immune response and has overall been well tolerated by the trial patients' bodies. This form of treatment may be especially useful for the study of gene expression in larger mammals whose larger body mass may obstruct clear visualization of deep tissue areas. The use of sstr2 and sstr5 as biomarkers to track the progress of and treat neuroendocrine tumors displaying circulating tumor cells is also being investigated due to these cells' somatostatin receptor gene expressivity. Therapeutic targeting Most pituitary adenomas express SSTR2, but other somatostatin receptors are also found. Somatostatin analogs (i.e. Octreotide, Lanreotide ) are used to stimulate these receptors, and thus to inhibit further tumor proliferation. Discovery There is a group of somatostatin receptors called the somatostatin receptor family. All of the members of the somatostatin receptor family are proteins that sit on the surface of the cell membrane and are responsible for the communication between cells. In 1972, scientists were on the trek to discover more information on the hypothalamus and its "release factors." Studies showed patterns of inhibitory activity of the hypothalamus release factors which led scientists in the direction to discover