Human Reproduction, Vol 13, 852-858, Copyright © 1998 by Oxford University Press
A Cano and JJ Tarin
Age and menopausal status were evaluated as potential modulators of the
progesterone action in the initiation of the mid-cycle luteinizing hormone
(LH) surge in women. Three distinct levels of oestradiol priming were used,
in combination with two different two-step ranks of progesterone
stimulation (10/25 mg and 25/50 mg i.m. injections of progesterone in oil,
over 2 consecutive days) in two groups of women, ten premenopausals, aged
between 18 and 25 years, and 14 postmenopausals, aged between 48 and 57
years. The low, moderate and high levels of oestradiol priming were defined
in the premenopausal group by days 5 and 9 of the cycle, and 0.4 mg
transdermal oestradiol applied in the early follicular phase respectively.
The corresponding situation in the postmenopausal women was defined by the
absence of treatment, 0.1 mg transdermal oestradiol, and 0.4 mg transdermal
oestradiol respectively. The oestradiol patches were maintained for 5 days,
and the first progesterone dose administered on day 3 of treatment.
Unambiguous LH surges, detected in serum and urine, were restricted to the
protocols using 0.4 mg oestradiol in both groups, with an onset soon after
progesterone administration. The surge was higher in the postmenopausal
group in serum and urine. The percentage LH increase above baseline,
however, was higher in the premenopausal women. The dose of progesterone
did not result in any changes in pituitary LH release. Therefore, the
oestradiol threshold for the progesterone stimulatory effect on LH release
was similar in both groups. The postmenopausal women did not yield
defective LH surges when adequately primed with oestradiol and
progesterone.
ARTICLES
Two distinct two-step ranks of progesterone stimulation after three different levels of oestrogen priming. Effect on induction of luteinizing hormone surges in young and climacteric women
Department of Paediatrics, Obstetrics and Gynecology, Facultad de Medicina, Valencia, Spain.
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