Nocturnal plasma melatonin and alpha-melanocyte stimulating hormone levels during exacerbation of multiple sclerosis.

The pineal gland has been implicated recently in the pathogenesis of multiple sclerosis (MS). To investigate this hypothesis further, we studied nocturnal plasma melatonin levels and the presence or absence of pineal calcification (PC) on CT scan in a cohort of 25 patients (5 men, 20 women; mean age: 41.1 years; SD = 11.1; range: 27-72) who were admitted to a hospital Neurology service for exacerbation of symptoms. Plasma alpha-melanocyte stimulating hormone (alpha-MSH) estimations were included in the study since there is evidence for a feedback inhibition between alpha-MSH and melatonin secretion. Abnormal melatonin levels were found in 13 patients (52.0%), 11 of whom had nocturnal levels which were below the daytime values (i.e., < 25 pg/ml). Although melatonin levels were unrelated to the patient's age and sex, there was a positive correlation with age of onset of symptoms (p < .0001) and an inverse correlation with the duration of illness (p < .05). PC was noted in 24 of 25 patients (96%) underscoring the pathogenetic relationship between MS and the pineal gland. Alpha-MSH levels were undetectable in 15 patients (60.0%), low in two patients (8.0%), normal in seven patients (28.0%), and elevated in one patient (4.0%). Collectively, abnormal alpha-MSH levels were found in over 70% of patients. These findings support the hypothesis that MS may be associated with pineal failure and suggest, furthermore, that alterations in the secretion of alpha-MSH also occur during exacerbation of symptoms. The relevance of these findings to the pathogenesis of MS are discussed.