Neuroactive steroid-serotonergic interaction: responses to an intravenous L-tryptophan challenge in women with premenstrual syndrome.
OBJECTIVE
To evaluate the circulating concentrations of the neuroactive steroids in response to an i.v. L-tryptophan (L-TP) challenge across the menstrual cycle in women with premenstrual syndrome (PMS) and in controls.


METHODS
An i.v. L-TP challenge was administered eight times during 1 month to five women with prospectively documented PMS and five age- and body mass-matched controls. Progesterone, allopregnanolone pregnenolone and 3alpha-5alpha-tetrahydrocorticosterone were assessed 15 and 0 min before, and at 30, 60 and 90 min after the challenge, across the menstrual cycle.


RESULTS
In response to L-TP challenge, only allopregnanolone concentrations were significantly increased across the cycle and this increase was of a greater magnitude in women with PMS. Pregnenolone and 3alpha-5alpha-tetrahydrocorticosterone concentrations were not affected in women with PMS or controls after L-TP challenge.


CONCLUSIONS
The data provide evidence for possible interaction between the serotonergic system and the neuroactive steroid, allopregnanolone. Women with PMS demonstrated a more significant increase in allopregnanolone concentrations in response to L-TP challenge, which could be due to an initial low basal serotonergic tone in the luteal phase in the PMS group.
Rasgon
N
N
Department of Psychiatry and Biobehavioral Sciences, Neuropsychiatric Institute, UCLA School of Medicine, Los Angeles, California 90095, USA.
Serra
M
M
Biggio
G
G
Pisu
M G
MG
Fairbanks
L
L
Tanavoli
S
S
Rapkin
A
A
D000328:Adult; D016022:Case-Control Studies; D003345:Corticosterone / Q000031:analogs & derivatives / Q000097:blood*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008597:Menstrual Cycle / Q000097:blood; D011284:Pregnenolone / Q000097:blood*; D011293:Premenstrual Syndrome / Q000097:blood* / Q000209:etiology; D011374:Progesterone / Q000097:blood*; D018709:Statistics, Nonparametric; D014364:Tryptophan / Q000008:administration & dosage*
D011374:Progesterone; C003676:tetrahydrocorticosterone; D011284:Pregnenolone; D014364:Tryptophan; D003345:Corticosterone