Pulsatile secretory characteristics of allopregnanolone, a neuroactive steroid, during the menstrual cycle and in amenorrheic subjects.
OBJECTIVE
To investigate whether allopregnanolone, a neuroactive steroid involved in modulating behavioural and neuroendocrine functions, shows episodic secretion in eumenorrheic women, during the follicular and luteal phases of the menstrual cycle, and in women with stress-induced amenorrhea.


METHODS
Six eumenorrheic women and 14 women with hypothalamic amenorrhea were enrolled for the present study.


METHODS
All subjects underwent hormonal evaluation in baseline conditions and a pulsatility study to determine LH, cortisol and allopregnanolone episodic release. Eumenorrheic subjects were investigated twice, in the follicular phase (days 3-7) and in the luteal phase (days 18-22) of the menstrual cycle. LH, FSH, prolactin, estradiol, phosphate, DHEA, allopregnanolone and cortisol levels were evaluated in each case.


RESULTS
In healthy women, serum gonadotropin and gonadal steroid levels were significantly lower (P<0.01 and P<0.05 respectively) than those in amenorrheic subjects. Allopregnanolone was higher in amenorrheic subjects and during the luteal phase, compared with the follicular phase, of eumenorrheic subjects (P<0.01). Pulse analysis revealed a significant episodic discharge of allopregnanolone in all subjects (follicular phase 6.5+/-0.3 peaks/6 h and luteal phase 5.5+/-0.4 peaks/6 h, hypothalamic amenorrhea 7.0+/-0.7 peaks/6 h) with higher pulse amplitude in amenorrheic subjects and during the luteal phase compared with the follicular phase of the eumenorrheic subjects (P<0.05). Moreover, the specific concordance index demonstrated that allopregnanolone is coupled with LH only during the luteal phase of the cycle and with cortisol during both phases. Allopregnanolone-cortisol coupling was also observed in amenorrheic subjects.


CONCLUSIONS
Allopregnanolone is secreted episodically. Both the ovary and adrenal glands release this steroid hormone and it shows temporal coupling with LH only during the luteal phase, with cortisol during both the studied phases of the menstrual cycle in eumenorrheic women and again with cortisol in hypothalamic amenorrheic patients.
Genazzani
Alessandro D
AD
Department of Obstetrics and Gynecology, University of Modena, Italy. algen@unimo.it
Luisi
Michele
M
Malavasi
Barbara
B
Strucchi
Claudia
C
Luisi
Stefano
S
Casarosa
Elena
E
Bernardi
Francesca
F
Genazzani
Andrea R
AR
Petraglia
Felice
F
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000568:Amenorrhea / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000097:blood*; D011280:Pregnanolone / Q000097:blood*
D007987:Gonadotropin-Releasing Hormone; D000324:Adrenocorticotropic Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D011280:Pregnanolone; D006854:Hydrocortisone