The Journal of endocrinology
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Oral contraceptives reduce menstrual pain but the interaction with vasopressin and prostaglandin F2 alpha, two uterine stimulants related to the condition, is unknown. Ten women with a history of moderate to severe dysmenorrhoea were studied. Repeated blood samples were taken during a first menstrual cycle without treatment, during the first 21 days of a second cycle when they received an oral contraceptive (150 micrograms levonorgestrel and 30 micrograms ethynyloestradiol) and on the first or second day of the bleeding following hormonal withdrawal. ⋯ M.) pmol/l) and at ovulation in the control cycle (1.91 +/- 0.58 pmol/l). During treatment the concentrations were consistently low, except on the first day of withdrawal bleeding (2.33 +/- 0.35 pmol/l). The concentrations of the prostaglandin F2 alpha metabolite showed less variation, but again the values at withdrawal bleeding (271 +/- 39 pmol/l) were not different from those obtained over the painful menstruations (255 +/- 24 and 217 +/- 25 pmol/l).(ABSTRACT TRUNCATED AT 250 WORDS)
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The effect of continuous oestrogen treatment on uterine weight, and on cytoplasmic and nuclear oestrogen receptors was examined in rabbits. Modulation of the effects of oestrogen by progesterone was also studied. Uterine weight increased successively after exposure to oestrogen from 1 to 6 days. ⋯ The oestrogen receptor concentration in both cytosolic and nuclear fractions decreased after 1 day but increased again after 3 days of progesterone treatment. The results indicated that there is a reduction in the actual concentration of oestrogen receptors in both cytosolic and nuclear fractions after continuous oestrogen treatment. The antagonism by progesterone of the effects produced by oestrogen appears to be transitory in nature, at least in the rabbit uterus.