Prolactinomas account for approximately 40% of all pituitary adenomas and are an important cause of hypogonadism and infertility. In our laboratory we are particularly interested in the development of new therapeutic targets for treatments against prolactinomas resistant to current therapies with dopaminergic agonists. In the pituitary, the function of progesterone in controlling lactotroph proliferation and prolactin secretion is controversial, and the involvement of membrane progesterone receptors (mPRs) is unknown. Dr Thomas is a worldwide referent in the study of mPRs. He has been working in the characterization of these receptors and their biological function during the last decade. Working with Dr Thomas will be a worthwhile experience. Results obtained would contribute to our better understanding of the role of progesterone and its receptors as well as contributing in our aim to obtain new and better therapeutic targets for pituitary tumor treatment.