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Effects of FSH on serum immunoreactive inhibin levels in the luteal phase of the menstrual cycle
Author(s) -
Burger Henry,
Hee Jennifer,
Bangah Mohan,
Prince Mirella,
McCloud Philip,
Ohara Akira,
Iwai Toshiko,
Mori Takahide
Publication year - 1996
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1996.8010811.x
Subject(s) - luteal phase , corpus luteum , endocrinology , medicine , follicular phase , ovulation , menstrual cycle , radioimmunoassay , follicle stimulating hormone , luteinizing hormone , hormone , chemistry
OBJECTIVE FSHcauses a dose‐related increase in circulating immunoreactive inhibin (INH) in the follicular phase of the menstrual cycle, while LH is the major stimulus to INH secretion by the corpus luteum. The present study was undertaken to assess whether FSH can also stimulate INH production during the luteal phase.DESIGN Normal volunteers were treated with a single injection of LH‐free FSH (Metrodin, 150 units) or saline as control, during the early, mid‐ or late luteal phase of the cycle, with subsequent hormone measurements.PATIENTS The 21 volunteers were aged 19–29. Seven subjects given FSH and 8 controls were studied in the early luteal phase, 1–4 days post ovulation. Eight FSH treated subjects and 10 controls were studied in the mid‐luteal phase, 5–9 days post ovulation, and 6 each, respectively, were studied in the late luteal phase.MEASUREMENTS Oestradiol (E 2 ), progesterone (P), and INH were measured by previously described radioimmunoassays.RESULTS In both the early and mid‐luteal phases, FSH caused a significant rise in INH (early, from 778 to 922 U/l, mid‐luteal 1553 to 2090 U/l) and E 2 (early 371 to 545 pmol/l, mid‐luteal 528 to 636) while there was no significant change in P. No significant changes occurred in the saline treated subjects. In the late luteal phase FSH prevented the significant fall in INH seen in the controls, whilst there was no effect on E 2 or P.CONCLUSIONS It was concluded that both FSH and LH are capable of modulating inhibin production during the luteal phase of the menstrual cycle. FSH may exert its actions on the corpus luteum or alternatively on developing follicles. The present study cannot clearly distinguish between these possibilities.