Members of the TGFβ family: role in lactotroph function and prolactinoma development
Erika Yanil Faraoni
University of California, San Diego
The main regulators of functions of the prolactin-secreting cells, lactotrophs, are dopamine and estradiol. In addition, other hypothalamic or pituitary factors contribute to these complex regulating network, among them, the locally produced members of the transforming growth factor beta (TGFβ) family. TGFβ1 is known for inhibiting lactotroph proliferation and prolactin secretion. Our group has recently reported reduced levels of these cytokine in three different experimental models of prolactinomas and proposed TGFβ1 as a therapeutic target for treatments against prolactinomas resistant to current therapies with dopaminergic agonists. Moreover, the role of other members of the TGFβ family in the lactotroph physiology have not been reported to date. Activins and inhibins belong to TGFβ family and are both synthesized and secreted in the pituitary. Our present goal is to study the activin/inhibin system (AIS) on lactotroph function and prolactinoma development. It is our interest to complete our preliminary results studying the mRNA and protein expression of AIS components, not in total pituitary, but in isolated normal and tumoral pituitary-derived lactotrophs, using immuno laser capture microdissection and double immunohistochemistry techniques. These results would fill a major gap in our understanding of AIS role in lactotroph physiology. This research is essential to continue later, in Argentina, in vivo studies in order to address remaining enigmas in the biological functions of AIS components in lactotroph pituitary adenomas.