Galanin is a small bioactive peptide whose synthesis is dramatically stimulated by estrogen. Estrogen also induces pituitary tumor formation in the rat. Immunogold histochemistry at the electron microscope level demonstrated that galanin is colocalized with prolactin and growth hormone within secretory granules of pituitary cells. Moreover, galanin gene expression and secretion in the anterior pituitary are regulated by dopamine and somatostatin in vivo. Studies on the distribution and regulation of galanin receptors in the hypothalamo-pituitary axis have also been initiated.
Current goals are to elucidate the roles of galanin in the hypothalamus and pituitary gland.
In particular, the relationships of galanin to prolactin and growth hormone secretion and pituitary tumor formation are being explored. Moore, Jr., J.P., D.G. Morrison and J.F. Hyde, Galanin gene expression is increased in the anterior pituitary gland of the human growth hormone-releasing hormone transgenic mouse. Hyde, J.F., D.G. Morrison, K.W. Drake, J.P. Moore, Jr., and B.E. Maley, Vasoactive intestinal peptide mRNA and peptide levels are decreased in the anterior pituitary of the human growth hormone-releasing hormone transgenic mouse. Hyde, J.F., J.P. Moore, Jr., K.W. Drake, and D.G. Morrison. Galanin gene expression in radiothyroidectomy-induced thyrotroph adenomas.