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J D Blaustein

Publications and source records attributed to J D Blaustein.

113 records · Page 7Linked to original sources

Ovarian hormones and meal patterns in rats: effects of progesterone and role of gastrointestinal transit.

Three experiments determined: (1) whether progesterone treatment would reverse the effects of estradiol benzoate (EB) on meal patterns of ovariectomized (OVX) rats, and (2) whether changes in gastrointestinal transit were responsible for the EB-induced changes in meal patterns. Progesterone (5 mg/day) reversed the effects of EB by increasing meal size and decreasing meal frequency in OVX, EB-treated rats. Progesterone had no effect on these measures in OVX rats that were not given EB. In a comparison of the rate of gastrointestinal transit, the rate of gastrointestinal transit was found to be faster in OVX rats injected with EB daily for two weeks than in OVX, oil-treated controls as measured under anesthesia with infusion of ten ml of liquid diet. However, this alteration in gastrointestinal transit does not appear to be responsible for the decreased meal size of EB-treated, OVX-rats, because the gastrointestinal changes are not observed 34-38 hr after an EB injection, a time at which meal size is already affected.

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Sequential inhibition of sexual behavior by progesterone in female rats: comparison with a synthetic antiestrogen.

When a large dose of progesterone was administered to ovariectomized rats 24 hr after a 2-microgram injection of estradiol benzoate (EB), sexual receptivity was inhibited at 54 hr (sequential inhibition). Larger doses of progesterone (1 mg) were required to inhibit the induction of sexual receptivity when tested at 54 hr than were necessary to facilitate at 30 hr. This inhibition was not due to copulatory stimuli from the first test, because inhibition occurred even when the first test was omitted. The inhibition was dose dependent on estradiol; increasing the EB priming dose offset the inhibition caused by 1 mg of progesterone. The results of an experiment that dissociated behaviorally the antiestrogenic action of progesterone from that of a synthetic antiestrogen, CI-628, are consistent with the notion that progesterone and synthetic antiestrogens inhibit the neural effects of estradiol by separate mechanisms of action.

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Concurrent inhibition of sexual behavior, but not brain [3H]estradiol uptake, by progesterone in female rats.

Chronic injections of high doses of progesterone (5 mg) and low doses of estradiol benzoate (EB; 2 microgram) resulted in less sexual behavior than did low doses of progesterone (.5 mg) and low doses of EB. In a typical procedure for inducing sexual behavior, EB and progesterone were given sequentially, separated by 42 hr. High levels of progesterone (2.5 and 5 mg) administered concurrently with EB inhibited the induction of sexual receptivity. Increasing the dose of EB from 2 microgram to 6 microgram or 10 microgram offset this inhibition. High doses of progesterone (5 mg) administered simultaneously or 2-16 hr prior to EB inhibited the induction of sexual behavior, but the inhibition waned when progesterone was administered 48 hr prior to EB. A single injection of progesterone (1 mg) that did not inhibit the induction of sexual behavior when administered concurrently with EB did inhibit lordosis when distributed into five injections (.2 mg) every 4 hr. The results of two experiments in which progesterone did not inhibit the uptake or retention of [3H]estradiol by brain cell nuclei suggest that the antiestrogenic action of progesterone in the central nervous system is not to interfere with the binding of estradiol.

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Effects of ovariectomy and estradiol on body weight and food intake in gold thioglucose-treated mice.

Two experiments investigated the effects of ovariectomy and estradiol replacement on the body weight and food intake of mice that had previously been treated with either gold thioglucose or saline. Ovariectomy and estradiol benzoate injections altered food intake in gold thioglucose-treated mice as much as in saline controls. Ovariectomy increased body weight in saline controls but it was without effect on the body weight of gold thioglucose-treated mice.

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