These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Action of luteinizing hormone-releasing factor (lrf) in the initiation of lordosis behavior in the estrone-primed ovariectomized female rat.
    Author: Moss RL, McCann SM.
    Journal: Neuroendocrinology; 1975; 17(4):309-18. PubMed ID: 806824.
    Abstract:
    In order to evaluate the precise role of luteinizing hormone-releasing factor (LRF) in mediating the onset of sexual behavior, the specificity, time-course, and dose-response relationship of LRF-facilitated lordosis behavior were determined. Ovariectomized female rats, pretreated with estrone and LRF, displayed a pattern of lordosis behavior which differed little from that produced by estrone-progesterone. Little if any lordosis behavior was observed in response to LRF alone, estrone alone, or estrone in combination with luteinizing hormone (LH), follicle-stimulating hormone (FSH), or thyrotropin-releasing factor (TRF). Furthermore, LRF-induced lordosis behavior occurred in the absence of the adrenals, thus eliminating adrenal progesterone as a factor in facilitating the appearnce of lordosis behavior. The LRF-facilitated lordosis behavior was seen 2 h after the injection of LRF and was maintained for a total of 8 h. A minimal dose of 150 ng LRF was required to initiate the first consistent appearance of lordosis behavior; the maximum response was obtained with 500 ng. It is thus suggested that LRF is not only responsible for the ovulatory discharge of LH and subsequent ovulation, but may also play a role in the initiation of the onset of mating behavior in the female rat. The action of luteinizing hormone-releasing factor (LRF) in the induction of lordosis behavior in ovariectomized rats (OVX) is described. 139 sexually experienced Sprague-Dawley female rats were ovariectomized at 80-100 days of age and behavioral testing was done 2-3 weeks later. At 9-10 months after ovariectomy adrenals were removed from 16 rats. These animals were given free access to isotonic NaCl solution. Female sexual behavior was expressed as the ratio of the number of lordosis responses to the number of mounts by the male rat. Ovarian hormones (estrone, E; theelin in oil 1 mg/ml) and progesterone (P; lipolutin in oil 50 mg/ml) were used. The pituitary hormones luteinizing hormone (LH) and follicle stimulating hormone (FSH) and releasing factors LRF and TRF were dissolved in physiological saline. All hormones were injected sc. In Experiment 1 to determine the specificity of LRF-induced lordosis responses 16 rats were tested under 8 conditions. Each rat was pretreated with either .25 ng E or 500 ng LRF. Tests for sexual receptivity were conducted 50 hours after E injections. After repeating these tests, adrenal removals (ADX) were done. After 5 days, the E-primed OVX-ADX animals were tested for sexual receptivity 50 hours following an injection of LRF (48 hours after E). In Experiment 2, to determine the time course for the initial appearance of lordosis and the total period of receptivity induced, 24 E-primed OVX rats were tested throughout and 8-hour period following the LRF injections. Each animal was primed with E at zero hour and given LRF at 48 hours. 49 hours after E injections tests were begun and continued at hourly intervals. This sequence was repeated at least 4 times. In Experiment 3, to determine the dose of LRF needed, 99 E-primed OVX rats were injected with doses ranging from 50 to 4000 ng LRF at 48 hours after E injections. Sexual receptivity tests were done 2 hours later. Results showed that sexual behavior in the female rat is dependent on the ovarian hormones estrogen and progesterone. Synthetic LRF exerted a facilitatory effect on the lordosis response. The LRF-facilitatory behavior was shown to be specific but LRF alone did not lead to mating behavior in OVX females. E-priming was a necessary condition to obtain a hgih level of copulatory behavior. The LRF-induced lordosis pattern was independent of adrenal progesterone and apparently not mediated by pituitary hormones. The time lag between LFR injection and induction of sexual behavior suggests that this is not a simple monosynaptic mechanism but may involve intermediate steps such as the activation of protein synthesis in the postsynaptic neurons of the mating center.
    [Abstract] [Full Text] [Related] [New Search]