Prolactin secretion is increased in patients with multiple sclerosis.

Before the onset and during experimental allergic encephalomyelitis (EAE), the animal counterpart of multiple sclerosis (MS), prolactin levels were found to be elevated and bromocriptine was found to attenuate the attacks. This study was designed to determine whether patients with MS show evidence of hyperprolactinemia. Twelve patients with MS and twelve healthy controls were studied at baseline and with TRH stimulation, a provocative test for prolactin secretion. Compared to matched controls, patients with MS had slightly but significantly higher prolactin levels at baseline (10.2+/-1.6 vs 6.4 4+/-0.57 ng/ml, P=0.042), however, values were within the normal range. The prolactin levels post TRH were significantly higher in patients with MS: peak prolactin level was higher in patients than controls (57.08+/-6.144 vs 32.94+/-4.92 ng/ml, P=0.006). The area under the curve of prolactin was also higher in patients than in controls (3421.87+/-394.53 vs 2317.62+/-257.22 ng/ml, P=0.030). These findings are compatible with data from studies of experimental animals with MS and suggest that prolactin may play a role in the immunology of MS.