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The CNS sites of action for progesterone facilitation of female sexual behavior are disputed. Among the areas most often cited are the ventromedial hypothalamus and the ventral midbrain. There is also a controversy about whether estradiol may substitute for progesterone for the facilitation of receptive behavior when given systemically or intracranially. We tested VMH and ventral midbrain applications of estradiol versus progesterone for the facilitation of female sexual behavior in estrogen-primed, ovariectomized female rats. Subjects were implanted with bilateral guide tubes aimed at ventral hypothalamic or midbrain sites. Estrogen-primed rats received either 28-gauge insert cannulae filled at the lumen with pure progesterone, estradiol, or cholesterol, or empty tubes, and were tested for receptivity with intact, experienced stud males just before, and 1 and 4 hr after, intracranial hormone administration. Significant estrous responsiveness was seen only in the 4-hr test after progesterone was implanted in the VMN in the first intracranial cannula test. We conclude, in contrast to some previous reports, that administration of progesterone to the VMN is more effective in the facilitation of female sexual behavior than when it is implanted in the ventral midbrain, and that administration of estradiol to either site is ineffective. 相似文献
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Facilitation of Sexual Receptivity by Ventromedial Hypothalamic Implants of the Antiprogestin RU 486
RU 486 is known primarily as an antagonist to progestins and glucocorticoids. However, RU 486 has also been shown to have agonistic progestational properties in biochemical and behavioral studies. In the current study, RU 486 was implanted directly into tim ventromedial hypothalamus (VMH) to test for facilitative action on the receptive behavior of female ovariectomized Long-Evans rats primed with 5 μg of estradiol benzoate. Cannulae containing RU 486, progesterone (P), or empty cannulae were implanted 48 hr after estrogen priming. The lordosis quotient and the lordosis score were assessed 4 hr after the cannulae were lowered by a standardized test consisting of 10 mounts by a stimulus male. P and RU 486 significantly facilitated receptivity compared to blank implants in terms of lordosis quotient and lordosis score, with no significant difference between the hormone treatments. While only a single dose of each treatment was given in the current study, RU 486 facilitated lordosis when implanted to the VMH as well as progesterone in contrast to our previous results where the steroids were administered systemically. 相似文献
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Two experiments examined the role of the steroid hormones, estradiol (E2), progesterone (P), and testosterone (T), in activating scent marking and 50-kHz ultrasonic vocalizations in ovariectomized Long-Evans rats in response to a devocalized male rat. In Experiment 1, females received, in a counterbalanced order, a series of six hormone treatments consisting of two injections (48-54 and 4 hr before behavioral tests). The six treatments were 8 micrograms E2 followed by 500 micrograms P or oil, 2 micrograms E2 followed by 500 micrograms P or oil, and oil followed by 500 micrograms P or oil. Injections of either the high or low dose of E2 followed by P resulted in high levels of vocalizations. Neither E2 by itself or P by itself were very effective. Surprisingly, none of the hormone treatments were effective in activating marking above the level seen when the females received control injections of oil. Four other hormone treatments were examined in Experiment 2: daily injections of 500 micrograms T, daily injections of 50 micrograms E2, implantation of silastic capsules of E2 (5% E2, 5 mm length) followed by 500-micrograms P injections before behavioral tests, and implantation of silastic capsules of E2 followed by oil injections. Animals receiving E2 by silastic capsule followed by P injection displayed the highest levels of marking and vocalizations across the five weekly tests. These results suggest that while E2 and P synergize for the display of female-typical behaviors similar to the hormonal regulation of lordosis, the mechanism of E2 action may be different for the two signaling behaviors. Scent marking appears to be responsive to the tonic levels of E2 released from silastic capsules. 相似文献
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The relationship between administration of progesterone and the display of patterns of receptive (response to the male) and preceptive (female initiated) sexual behavior was examined in ovariectomized, estrogen-primed female rats in a “restrained male” test situation. It was found that the degree of receptivity and proceptivity displayed was directly proportional to progesterone dose and time from progesterone injection (up to 4.5 hr). Higher progesterone doses and longer period of time from progesterone injection (up to 4.5 hr) were both associated with shorter latencies to return to the male following intromission and ejaculation. Receptivity could be induced with estrogen alone but progesterone was required for the display of proceptivity and higher doses of progesterone were needed to effect increases in proceptivity relative to receptivity. Proceptive behavior also occurred in a narrower time range than did receptive behavior. Receptivity alone is characterized as the lowest degree, and receptivity plus proceptivity as the highest degree, of expression of the total behavior pattern of the estrous female rat. Receptivity and proceptivity together constitute a continuum of estrous responsiveness. Increasing the progesterone dose from 0 to 200 μg, and increasing the latency from progesterone injection from 0 to 4.5 hr, were associated with increasing degree of expression of the total behavioral continuum. 相似文献
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Background
In addition to known protein-coding genes, large amounts of apparently non-coding sequence are conserved between the human and mouse genomes. It seems reasonable to assume that these conserved regions are more likely to contain functional elements than less-conserved portions of the genome. 相似文献10.
van Dijken JP Bauer J Brambilla L Duboc P Francois JM Gancedo C Giuseppin ML Heijnen JJ Hoare M Lange HC Madden EA Niederberger P Nielsen J Parrou JL Petit T Porro D Reuss M van Riel N Rizzi M Steensma HY Verrips CT Vindeløv J Pronk JT 《Enzyme and microbial technology》2000,26(9-10):706-714
To select a Saccharomyces cerevisiae reference strain amenable to experimental techniques used in (molecular) genetic, physiological and biochemical engineering research, a variety of properties were studied in four diploid, prototrophic laboratory strains. The following parameters were investigated: 1) maximum specific growth rate in shake-flask cultures; 2) biomass yields on glucose during growth on defined media in batch cultures and steady-state chemostat cultures under controlled conditions with respect to pH and dissolved oxygen concentration; 3) the critical specific growth rate above which aerobic fermentation becomes apparent in glucose-limited accelerostat cultures; 4) sporulation and mating efficiency; and 5) transformation efficiency via the lithium-acetate, bicine, and electroporation methods. On the basis of physiological as well as genetic properties, strains from the CEN.PK family were selected as a platform for cell-factory research on the stoichiometry and kinetics of growth and product formation. 相似文献