Background. Abnormalities of brain serotonin (5-HT)
transmission have been implicated in the
pathophysiology of bulimia nervosa (BN), but no conclusive data have yet
been provided. The
purpose of this study was to assess 5-HT transmission via the measurement
of the prolactin (PRL)
response to the specific 5-HT releasing agent d-fenfluramine
(d-FEN) in both patients with BN and comparison subjects.
Methods. According to a double-blind placebo-controlled
design, plasma PRL response to d-FEN
was measured in 14 drug-free bulimics and 14 matched healthy controls.
In both patients and
controls, eating-related psychopathology, depressive and obsessive–compulsive
symptoms, and aggressiveness were measured by rating scales.
Results. Baseline plasma levels of PRL and 17β-oestradiol
were significantly reduced in bulimic
patients, whereas basal plasma levels of cortisol did not significantly
differ from healthy controls.
PRL response to d-FEN was not different between patients and
controls as groups, but it was
significantly blunted in bulimics with high frequency bingeing
([ges ]2 binge episodes per day; N=7)
as compared to both those with low frequency bingeing ([les ]1 binge
episode per day; N=7) and
matched controls. A significant negative correlation emerged between the
frequency of binge
episodes and the hormone response to d-FEN. Moreover,
although patients scored higher than
healthy subjects on rating scales assessing depressive and
obsessive–compulsive symptoms and
aggressiveness, no significant correlation was found between these measures
and the PRL response
to d-FEN.
Conclusions. These results support the idea that serotonin
transmission is impaired in bulimic
patients with frequent binge episodes.