Background: Multiple sclerosis (MS) is the most common demyelinating disorderof the central nervous system and is considered to be multifactorial with an autoimmune component. Prolactin(PRL) is a neuroendocrine peptide with potent immunomodulatory properties. Hyperprolactinemia enhancesseveral autoimmune disorders and may play a role in the pathogenesis of MS. The aim of this study wasto compare serum PRL levels in MS patients with those of healthy controls. Material/Methods: There were43 patients with definite MS and 43 sex- and age-matched healthy controls. Conditions leading to a risein PRL, such as pregnancy, lactation, and specific underlying diseases and drugs, were excluded. PRLlevels were measured in fasting blood samples. For the MS group, disease duration and subtype, clinicalmanifestations, and expanded disability status scores (EDSS) were also recorded. Results: There wereno significant differences in serum PRL levels between the case and control groups in both women andmen (376.78+/-231.11 mIU/l in female patients with MS vs. 364.19+/-202.55 mIU/l in female controls, 266.00+/-200.83mIU/l in male patients with MS vs. 197.25+/-65.25 mIU/l in male controls). We also found no significantrelationship between PRL and disease activity, disease duration, and EDSS. Conclusions: Our findingsdo not support the hypothesis that MS patients are in a hyperprolactinemic state. However, further studiesin more homogenous MS subgroups are needed.

Keywords: Case-Control Studies, Hyperprolactinemia - complications, Models, Biological, Multiple Sclerosis - etiology, Multiple Sclerosis, Chronic Progressive - etiology, Multiple Sclerosis, Relapsing-Remitting - etiology, Prolactin - blood