ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract: The ability of Catecholestrogens to induce cytosolic progestin binding sites in the hypothalamus, pituitary gland and uterus of ovariectomised-adrenal-ectomised rats was demonstrated by the increase in high-affinity [3H]promegestone binding sites (KD 1.39,0.50 and 0.54 n M, respectively) following a single subcutaneous injection (26.4 μg/animal) of the 3, 4-dibenzoate ester of 4-hydroxyestradiol. The affinity and the time course of induction of these binding sites were very similar to those after a single injection of an equivalent dose (20 (μg/animal) of estradiol 3-benzoate, exhibiting maximal receptor levels after 44 h. Widely differing efficacies in the induction of progestin binding sites were observed between the dibenzoate esters of 2- and 4-hydroxyestradiol. 2-Hydroxyestradiol 2, 3-dibenzoate was ineffective in the pituitary gland up to a dose of 132 μg/ animal, whereas 4-hydroxyestradiol dibenzoate was equi-potent to estradiol benzoate, showing a maximal induction of progestin binding sites at single doses in the range of 13.2–26.4 μg/animal (equivalent to 10–20 μg of estradiol benzoate). As compared to the pituitary gland, the uterus was much more sensitive to the systemic administration of estrogen benzoates. At single doses in the range of 1.32–6.6 μg/animal (equivalent to 1–5 μg of estradiol benzoate), 4-hydroxyestradiol dibenzoate induced maximal levels of progestin receptors and even 2-hydroxyestradiol dibenzoate, when given at a high dose (132.4 μg/animal, equivalent to 100 μg of estradiol benzoate), produced a slight increase in progestin binding sites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1983.tb11307.x
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