Seasonal variation in plasma prolactin response to D-fenfluramine in healthy subjects.
To assess dynamically a seasonal variation in the functioning of the central serotonin (5-HT) system, we investigated the prolactin (PRL) response to the specific serotonergic agent D-fenfluramine (D-FEN) in the different seasons of the year. Thirteen healthy women and 11 healthy men (six for each season), aged 20-50 years, received PO 30 mg D-FEN and placebo, according to a randomized double-blind design. As compared to placebo, D-FEN induced a clear-cut increase in plasma PRL levels in all the seasons; this response was higher in fall than in spring and summer (p < .01 and < .05, respectively). In all the subjects, as a group, the hormone response to the 5-HT probe was inversely correlated with the body weight and age. These results document a seasonal variability in the PRL response to D-FEN, which suggests a seasonal fluctuation in central 5-HT transmission in healthy humans.
Monteleone
P
P
Institute of Psychiatry, Second University of Naples, Italy.
La Rocca
A
A
Fuschino
A
A
Bortolotti
F
F
Maj
M
M
D000328:Adult; D004311:Double-Blind Method; D005260:Female; D005277:Fenfluramine / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008875:Middle Aged; D010919:Placebos; D011388:Prolactin / Q000097:blood*; D012621:Seasons; D018490:Serotonin Agents / Q000494:pharmacology*; D012727:Sex Characteristics
D010919:Placebos; D018490:Serotonin Agents; D005277:Fenfluramine; D011388:Prolactin; D006854:Hydrocortisone