Endocrine Abstracts

Background: Pituitary tumours are commonly benign adenomas, accounting for 10-15% of all intracranial neoplasms. Among functioning pituitary tumours, prolactinomas are the most frequently observed in the clinic (about 40%). Dopamine, acting through the dopamine type 2 receptor (Drd2), is the main inhibitor of lactotroph proliferation and prolactin secretion, therefore, these tumours are usually treated with dopaminergic agonists with a high efficiency. However, there is a subs...

Serum prolactin levels increase progressively from birth to adulthood in female and male rats, being higher in females from birth. Although this gradual increase was associated with concomitant maturation of prolactin-releasing and -inhibiting factors, these processes do not fully explain some sex differences observed. In in vitro studies, using lactotrophs in culture, from rats of different ages, in the absence of hypothalamic control, it was shown that the secretion...

Molecular mechanisms involved in lactotrophs cell proliferation that led to prolactinoma development are not fully understood. Cyclin-dependant kinase (CDK) p27Kip1 is a key cell cycle regulator, and it is regulated by Menin. The transgenic mice model MEN1+/-, as the p27 -/- knock-out mice, develop pituitary adenomas and other neuroendocrine tumours. Menin can also interfere with phosphorylated AKT (pAKT) function, known for i...