Stimulation of sexual behavior in the male rat by galanin-like peptide

Fraley, Gregory S.; Thomas-Smith, Siobhan; Acohido, Blake V.; Steiner, Robert A.; Clifton, Donald K.

doi:10.1016/j.yhbeh.2004.04.008

Cited by 41 publications

(28 citation statements)

References 38 publications

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“…POMC also decreases food intake and stimulates endocrine reproductive physiology (Finn, Pau, Spies, Cunningham, Clifton, and Steiner, 2000;Kalra, Dube, Pu, Xu, Horvath, and Kalra, 1999;Thornton, Cheung, Clifton, and Steiner, 1997). Conversely, central injections of galanin-like peptide (GALP) decrease food intake and body weight (Krasnow, Fraley, Schuh, Baumgartner, Clifton, and Steiner, 2003;Seth, Stanley, Dhillo, Murphy, Ghatei, and Bloom, 2003), but stimulate sex behavior and LH secretion in male rats (Fraley, Thomas-Smith, Acohido, Steiner, and Clifton, 2004;Krasnow et al, 2003). The results of this current study show that rat RFRP-3 fits into this hypothalamic motif; RFRP-3 suppresses sex behavior while increasing food intake-similarly to that observed in the chick (Tachibana, Sato, Takahashi, Ukena, Tsutsui, and Furuse, 2005).…”

Section: Discussionsupporting

confidence: 62%

Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat

Johnson

Tsutsui

Fraley

2007

Hormones and Behavior

350

383

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A recently described avian neuropeptide, gonadotropin inhibitory hormone (GnIH), has been shown to have seasonal regulatory effects on the hypothalamic-pituitary-gonadotropin axis (HPG) in several avian species. In the bird, GnIH expression is increased during the photorefractory period and has inhibitory effects on the HPG. A recently described mammalian neuropeptide, RF-amide-related peptide-3 (RFRP-3), may be genetically related and functionally similar to this avian neuropeptide. The purposes of this study were to first see if rat RFRP-3 is expressed in the male rat brain and second to determine if ICV injections of RFRP-3 will have effects on feeding and sex behaviors, as well as hormone release from the anterior pituitary. Results confirm other studies in that immunoreactive cell bodies and fibers are observable in areas of the male rat brain known to control the HPG and feeding and sex behaviors. RFRP-3 fibers are also observed in close proximity to GnRH immunoreactive cell bodies. Behavioral tests indicate that high but not low ICV RFRP-3 (500 vs. 100 ng, respectively) significantly (p < 0.05) suppressed all facets of male sex behavior while not having any observable effects on their ability to ambulate. Sex behavior was later exhibited when those same male rats received the ICV vehicle. While suppressing sex behavior, ICV RFRP-3 significantly (p < 0.05) increased food intake compared to controls. ICV RFRP-3 also significantly reduced plasma levels of luteinizing hormone but increased growth hormone regardless of the time of day; however, at no time did RFRP-3 alter plasma levels of FSH, thyroid hormone, or cortisol. These results indicate that although RFRP-3 has similar effects on LH as observed with GnIH in avian species, in the rat RFRP-3 has additional roles in regulating feeding and growth.

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Section: Discussionsupporting

confidence: 62%

Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat

Johnson

Tsutsui

Fraley

2007

Hormones and Behavior

350

383

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“…The animals were maintained on a 12:12-h light:dark cycle, with lights on at 0700. To minimize the effects of the "novelty" of the behavioral tests, all animals were given three bouts of sexual experience before the beginning of the experiment (6). All procedures were approved by the Hope College Animal Care and Use Committee, in accordance with the National Institutes of Health Guide for Care and Use of Laboratory Animals.…”

Section: Methodsmentioning

confidence: 99%

Galanin-Like Peptide Rescues Reproductive Function in the Diabetic Rat

et al. 2005

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Galanin-like peptide (GALP) is expressed in the hypothalamic arcuate nucleus and is regulated by leptin and insulin. Centrally administered GALP stimulates gonadotropin secretion and sexual behavior in the rat. Type 1 diabetes is associated with reduced expression of GALP, as well as an overall decline in reproductive function. We postulated that tonic activity of GALP in the brain is required to sustain normal reproductive activity. To test this hypothesis, we examined whether central (intracerebroventricular) immunoblockade of GALP would reduce sexual behaviors and serum levels of luteinizing hormone (LH) in normal adult male rats. We found that GALP antibody reversibly reduced serum levels of LH and abolished male sexual behaviors (P < 0.05 and 0.001, respectively). Second, we tested whether intracerebroventricular GALP could restore normal plasma LH levels and sexual behavior in diabetic animals. We compared groups of diabetic rats that received intracerebroventricular GALP or vehicle and found that GALP increased serum levels of LH and sexual behavior. Third, we examined whether intracerebroventricular administration of affinity-purified GALP antibody could block the effect of insulin and leptin in reversing the effects of diabetes on LH and sexual behavior. We found that treatment of diabetic animals with insulin and leptin nearly normalized LH levels and sexual behaviors; however, this effect was attenuated by intracerebroventricular administration of GALP antibody (P < 0.05). These observations demonstrate that endogenous GALP provides trophic support to the neuroendocrine reproductive axis, including sexual behavior. Diabetes 54:2471-2476, 2005 D eviations of normal metabolism and nutrition can disrupt reproduction. The activity of the reproductive axis may be altered by changes in circulating levels of metabolic hormones such as leptin and insulin, whose blood levels typically reflect an animal's metabolic status and fuel reserves (1). Reproductive dysfunction is common in metabolic diseases, such as type 1 and type 2 diabetes (2,3; rev. in 4). Sexual dysfunction in diabetes is thought to be attributable to a central neuropathy (5); however, the cellular and molecular etiology of this phenomenon is unknown. It seems plausible that the reproductive dysfunction associated with diabetes is caused by a disruption in the cellular and molecular targets in the brain for insulin and other metabolic factors that may be altered in diabetes. Neurons that produce galanin-like peptide (GALP) are prime candidates for mediating this phenomenon.GALP is a neuropeptide that is expressed in the arcuate nucleus of the hypothalamus and has been implicated in the regulation of gonadotropin-releasing hormone. Central infusions of GALP stimulate the secretion of gonadotropin-releasing hormone as well as luteinizing hormone (LH) and induce all aspects of sexual behavior in the male rat (6 -9). GALP has also been implicated in the neuroendocrine regulation of feeding and body weight (7,10 -12). Fasting and uncontrolled diabetes...

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“…Further to its effects on reproductive hormones, GALP was shown to increase male sexual behavior in rats, whereas galanin inhibited it, and the effect of GALP was maintained in castrated rats, suggesting effects independent of testosterone secretion (Fraley et al, 2004b). In more recent comparative studies in adult, ovariectomized, female mice primed with estradiol and progesterone, GALP infusion increased LH secretion, and the response was blocked by pretreatment with a GnRH 1 antagonist.…”

Section: Actions Of Galanin-like Peptide In the Normal Brain And mentioning

confidence: 98%