Prolactin effects on the pathogenesis of diabetes mellitus

Abstract Background Prolactin (PRL) is a pituitary hormone promoting lactation in response to the suckling reflex. Beyond its well‐known effects, novel tissue‐specific and metabolic functions of PRL are emerging. Aims To dissect PRL as a critical mediator of whole‐body gluco‐insulinemic sensitivity. Methods PubMed‐based search with the following terms ‘prolactin’, ‘glucose metabolism’, ‘type 2 diabetes mellitus’, ‘type 1 diabetes mellitus’, ‘gestational diabetes mellitus’ was performed. Discussion The identification of the PRL‐glucose metabolism network poses the basis for unprecedented avenues of research in the pathogenesis of diabetes mellitus type 1 or 2, as well as of gestational diabetes. In this regard, it is of timely relevance to define properly the homeostatic PRL serum levels since glucose metabolism could be influenced by the circulating amount of the hormone. Results This review underscores the basic mechanisms of regulation of pancreatic β‐cell functions by PRL and provides a revision of articles which have investigated the connection between PRL unbalancing and diabetes mellitus. Future studies are needed to elucidate the burden and the role of PRL in the regulation of glucose metabolism and determine the specific PRL threshold that may impact the management of diabetes. Conclusion A careful evaluation and context‐driven interpretation of PRL levels (e.g., pregnancy, PRL‐secreting pituitary adenomas, drug‐related hyper‐ and hypoprolactinemia) could be critical for the correct screening and management of glucometabolic disorders, such as type 1 or 2 as well as gestational diabetes mellitus.