Serum levels of insulin-like growth factor I and insulin-like growth factor-binding protein-1 and -3 in women with regular menstrual cycles.
OBJECTIVE
To investigate the cyclic changes of serum insulin-like growth factor (IGF-I), IGF-binding protein-1 (IGFBP-1) and IGFBP-3 levels during ovulatory menstrual cycle.


METHODS
A prospective study following a preset protocol.


METHODS
A tertiary-care academic medical center.


METHODS
Thirty young female adults with regular menstrual cycles were recruited (18 with normal luteal phase and 12 with inadequate luteal function confirmed by serum P levels).


METHODS
Serum concentrations of IGF-I, IGFBP-1, and IGFBP-3 from women with regular menstrual cycles were assayed. Circulating E2 and P levels also were determined to certify the ovulatory cycles.


RESULTS
In women with normal luteal function, there was a peak of serum IGFBP-1 levels before ovulation concomitant with the preovulatory E2 peak. The nadir of serum IGFBP-1 levels was in the midluteal phase. Circulating IGFBP-1 elevated rapidly during late luteal phase and reached a peak on the 1st day of menstruation then declined slightly until a preovulatory IGFBP-1 peak occurred. In women with inadequate luteal function (midluteal serum levels of P < 10 ng/mL [conversion factor to SI unit, 3.180]), the preovulatory increase in serum IGFBP-1 was not significant and the circulating IGFBP-1 levels fluctuated throughout the menstrual cycle except for a unique peak of serum IGFBP-1 on the 1st day of menstruation. By contrast, there were no cyclic changes of serum IGF-I and IGFBP-3 levels in women with regular menstrual cycles, including both normal nad inadequate luteal functions.


CONCLUSIONS
The preovulatory increase in serum IGFBP-1 levels may be of follicular origin and associated with the subsequent luteal function in females with ovulatory cycles. However, the involvement of IGFBP-1 in the process of follicular maturation and luteogenesis, as well as the regulation of luteal function, needs to be explored further.
Wang
H S
HS
Department of Obstetrics and Gynecology, Chang-Gung Medical School, Chang-Gung Memorial Hospital, Lin-Kou Medical Center, Taipei, Taiwan, Republic of China.
Lee
J D
JD
Soong
Y K
YK
D000328:Adult; D002352:Carrier Proteins / Q000097:blood*; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008597:Menstrual Cycle / Q000502:physiology*; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies
D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D018969:Insulin-Like Growth Factor Binding Proteins; D011374:Progesterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I