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Changes in pituitary response to GnRH during the luteal‐follicular transition of the human menstrual cycle
Author(s) -
Messinis I. E.,
Koutsoyiannis D.,
Milingos S.,
Tsahallna E.,
Seferiadis K.,
Lolis D.,
Templeton A. A.
Publication year - 1993
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 - 10.1111/j.1365-2265.1993.tb00988.x
Subject(s) - luteal phase , endocrinology , medicine , follicular phase , basal (medicine) , menstrual cycle , luteinizing hormone , menstruation , follicle stimulating hormone , biology , hormone , insulin
Summary OBJECTIVE We studied changes in pituitary response to GnRH during the luteal‐follicular transition of the human menstrual cycle. DESIGN Normally cycling women were investigated during two consecutive menstrual cycles. In each woman, GnRH tests were performed during the two LH surges and several times during the luteal‐follicular transition. Data for analysis were available in all women on days −8, −6, −4, −2, −1,1, 2, 3, 4, 5 and 7 in relation to the onset of second menstruation (day 1). PATIENTS Five normally ovulating parous women were studied. MEASUREMENTS Pituitary response to GnRH was calculated as the net increase in LH and FSH at 30 minutes (ΔLH and ΔFSH) above the basal value. RESULTS ΔLH and ΔFSH showed a similar pattern of significant changes during the luteal‐follicular transition. They decreased progressively from days −8 to 1 and increased on day 2. ΔLH and ΔFSH then decreased on days 3 and 4 and showed a further increase on days 5 and 7. In contrast to these changes, basal FSH levels increased from days −2 to 1 and remained high up to day 5, while basal LH levels showed a trend to increase only after the onset of menses. CONCLUSIONS These results demonstrate that the increase In basal FSH secretion during the luteal‐follicular transition is GnRH independent. It is suggested that LH and FSH release under the stimulation by GnRH is regulated by a common mechanism.