scholarly journals Environmental-Like Exposure to Low Levels of Estrogen Affects Sexual Behavior and Physiology of Female Rats

Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5592-5598 ◽  
Author(s):  
Daniele Della Seta ◽  
Francesca Farabollini ◽  
Francesco Dessì-Fulgheri ◽  
Leonida Fusani
Keyword(s):  
Sexual Behavior ◽  
Estrous Cycle ◽  
Environmental Exposure ◽  
Reproductive Behavior ◽  
Plasma Levels ◽  
Time Course ◽  
Endocrine Disrupting Chemicals ◽  
Female Rats ◽  
Sprague Dawley ◽  
Female Sexual Behavior

Xenoestrogens are endocrine-disrupting chemicals that mimic the action of endogenous estrogen hormones. Effects of xenoestrogen on aquatic wildlife are well documented, whereas the experimental evidence for impairment of reproductive behavior and physiology in mammals after exposure to xenoestrogens has been debated. The strongest arguments against such studies have been that the route, time course, and intensity of exposure did not simulate environmental exposure and that the chemicals tested have additional nonestrogenic toxic effects, hindering generalization of actual xenoestrogenic effects. Here we show that environmental-like exposure to the pure estrogen 17α-ethinylestradiol during development alters reproductive behavior and physiology in adult female Sprague-Dawley rats. We simulated environmental exposure by giving low doses (0.4 and 0.004 μg/kg·d) of 17α-ethinylestradiol orally to pregnant females from conception to weaning of the pups, which continued to receive the treatment until puberty. We studied the sexual behavior, estrous cycle, and estradiol plasma levels of intact female rats when they reached 3 months of age. Exposure to the higher dose strongly affected female sexual behavior and physiology, with suppression of lordosis and the estrous cycle and enhanced aggression toward males. The lower dose disrupted appetitive components of sexual behavior that influence the rate of copulation. Estradiol plasma levels were not affected by the treatment. Our study revealed that exposure to low oral doses of a pure estrogen during development alters female sexual behavior and physiology. These results suggest potential risks of reproductive failure from xenoestrogen exposure in realistic ecological conditions.

Sexual dimorphism in vasopressin-induced contraction of rat aorta

1991 ◽  
Vol 260 (2) ◽  
pp. H453-H458 ◽  
Author(s):  
J. N. Stallone ◽  
J. T. Crofton ◽  
L. Share
Keyword(s):  
Estrous Cycle ◽  
Vascular Reactivity ◽  
Rat Aorta ◽  
Isometric Tension ◽  
Female Rats ◽  
Male Rats ◽  
Maximal Response ◽  
Sprague Dawley ◽  
Tension Development ◽  
Sprague Dawley Rats

Previously, we reported that, in the rat, pressor responsiveness to vasopressin (VP) is higher in males than in females during most phases of the estrous cycle. To explore the role of the vasculature in this phenomenon, we examined vascular reactivity to VP in thoracic aortas of male rats and female rats during each phase of the estrous cycle. Aortic rings were prepared from age-matched male and female Sprague-Dawley rats and mounted for isometric tension recording. Maximal response of female aortas to VP (4,246 +/- 163 mg/mg ring dry wt) was more than twice (P less than 0.001) that of male aortas (1,877 +/- 215 mg/mg ring wt). Sensitivity of female aortas to VP was substantially higher (P less than 0.001) than that of male aortas (EC50: 10.9 +/- 0.7 vs. 19.0 +/- 1.6 nM, respectively). Maximal rate of tension development (dT/dtmax) during contraction with VP was nearly twofold higher (P less than 0.01) in female aortas (536 +/- 23 mg/min) than in male aortas (300 +/- 19 mg/min). Maximal response, sensitivity, and dT/dtmax of female aortas did not vary significantly during the estrous cycle. Maximal response of female aortas to phenylephrine (PE; 1,251 +/- 93 mg/mg ring wt) was half that (P less than 0.001) of male aortas (2,546 +/- 194 mg/mg ring wt); sensitivity to PE did not differ significantly (EC50: 0.33 +/- 0.02 vs. 0.38 +/- 0.06 microM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a role for the neurosteroid allopregnanolone in the modulation of reproductive function in female rats

1995 ◽  
Vol 133 (3) ◽  
pp. 375-380 ◽  
Author(s):  
Andrea R Genazzani ◽  
Marco A Palumbo ◽  
Antonio A de Micheroux ◽  
Paolo G Artini ◽  
Mario Criscuolo ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Liquid Chromatography ◽  
Estrous Cycle ◽  
Brain Cortex ◽  
Reproductive Function ◽  
Ovulation Rate ◽  
Female Rats ◽  
Obstetrics And Gynecology ◽  
Intracerebroventricular Injection ◽  
Medial Basal Hypothalamus

Genazzani AR, Palumbo MA, de Micheroux AA, Artini PG, Criscuolo M, Ficarra G, Guo A-L, Benelli A, Bertolini A, Petraglia E. Purdy RH. Evidence for a role for the neurosteroid allopregnanolone in the modulation of reproductive function in female rats. Eur J Endocrinol 1995;133:375–80. ISSN 0804–4643 The present study investigated the effect of allopregnanolone (5α-pregnan-3α-ol-20-one) or of passive immunoneutralization of brain allopregnanolone, the most potent steroid produced by neurons, on ovulation rate and sexual behavior in female rats. Allopregnanolone was injected intracerebroventricularly in rats on diestrus and proestrus and tests were done on estrus. The intracerebroventricular injection of allopregnanolone significantly decreased the number of oocytes collected on estrus (p < 0.01). To support a physiological involvement, antiserum to allopregnanolone was injected centrally to block the activity of the endogenous neurosteroid. When administered on diestrus and proestrus or only on proestrus, the antiserum was shown to be correlated with a significant increase (p < 0.01) in oocytes retrieved on estrus. In female rats treated with antiserum to allopregnanolone, the lordosis intensity was augmented significantly as compared to controls. Finally, the possible changes of medial basal hypothalamus concentration of allopregnanolone throughout the estrous cycle and at the time of ovulation were investigated. Hypothalamic extracts were eluted on highpressure liquid chromatography and allopregnanolone concentration was measured by radioimmunoassay. Brain cortex was used as control tissue. Hypothalamic allopregnanolone concentration on proestrus morning and afternoon was found to be significantly lower than in the remaining phases of the estrous cycle (p < 0.01), while no significant changes were observed in brain cortex concentration of allopregnanolone. The present results suggest that hypothalamic allopregnanolone may be involved in the mechanism of ovulation, affecting hormonal and behavioral events. AR Genazzani, Institute of Obstetrics and Gynecology, University of Pisa, via Roma 67, 56100 Pisa, Italy

scholarly journals Effects of the estrous cycle and ovarian hormones on cue-triggered motivation and intrinsic excitability of medium spiny neurons in the Nucleus Accumbens of female rats

2019 ◽  
Author(s):  
Yanaira Alonso-Caraballo ◽  
Carrie R. Ferrario
Keyword(s):  
Food Intake ◽  
Estrous Cycle ◽  
Ovarian Hormones ◽  
Female Rats ◽  
Intrinsic Excitability ◽  
Sprague Dawley ◽  
Food Cues ◽  
Approach Behavior ◽  
Individual Susceptibility ◽  
Conditioned Approach

AbstractNaturally occurring alterations in estradiol influence food intake in females. However, how motivational responses to food cues are affected by the estrous cycle or ovarian hormones is unknown. In addition, while individual susceptibility to obesity is accompanied by enhanced incentive motivational responses to food cues and increased NAc intrinsic excitability in males, studies in females are absent. Here, we examined basal differences in intrinsic NAc excitability of obesity-prone vs. obesity-resistant females and determined how conditioned approach (a measure of cue-triggered motivation), food intake, and motivation for food vary with the cycle in naturally cycling female obesity-prone, obesity-resistant, and outbred Sprague-Dawley rats. Finally, we used ovariectomy followed by hormone treatment to determine the role of ovarian hormones in cue-triggered motivation in selectively-bred and outbred female rats. We found that intrinsic excitability of NAc MSNs and conditioned approach are enhanced in female obesity-prone vs. obesity-resistant rats. These effects were driven by greater MSN excitability and conditioned approach behavior during metestrus/diestrus vs. proestrus/estrus in obesity-prone but not obesity-resistant rats, despite similar regulation of food intake and food motivation by the cycle in these groups. Furthermore, estradiol and progesterone treatment reduced conditioned approach behavior in obesity-prone and outbred Sprague-Dawley females. To our knowledge, these data are the first to demonstrate cycle- and hormone-dependent effects on the motivational response to a food cue, and the only studies to date to determine how individual susceptibility to obesity influences NAc excitability, cue-triggered food-seeking, and differences in the regulation of these neurobehavioral responses by the cycle.

scholarly journals Modeling Individual Recovery after Peripheral Nerve Injury in Rats and the Effects of Parturition

2014 ◽  
Vol 121 (5) ◽  
pp. 1056-1067 ◽  
Author(s):  
Carol A. Aschenbrenner ◽  
Timothy T. Houle ◽  
Silvia Gutierrez ◽  
James C. Eisenach
Keyword(s):  
Nerve Injury ◽  
Growth Curve ◽  
Postpartum Period ◽  
Repeated Measures ◽  
Time Course ◽  
Female Rats ◽  
Growth Curve Analysis ◽  
Sprague Dawley ◽  
Male And Female Rats ◽  
Study Results

Abstract Background: Recovery from pain after surgery exhibits large interindividual variability, with very slow recovery equated to chronic pain. Surgical injury in the postpartum period modestly increases initial recovery after major nerve injury. In this study, the authors use a nerve injury that recovers over 2 to 3 months and apply growth curve modeling to further understand the effect of the postpartum period on speed of recovery. Methods: Withdrawal threshold to mechanical stimulus on the hind paw was determined in 41 Sprague–Dawley rats before and for 10 weeks after partial spinal nerve ligation. Age-matched male and female rats and postpartum females with pups or those separated from pups at delivery were studied. Growth curve analyses were applied to model recovery after surgery despite varying timing of measurements across groups and missing data, and these results were compared with those of two-way repeated-measures ANOVA. Results: The recovery time course was similar between males and females. In contrast, recovery was hastened in the postpartum groups, with nonoverlapping 95% CIs of modeled trajectories between days 6 and 66 after surgery. CIs were more precise at most time periods with growth curve analysis compared with ANOVA. Conclusions: The authors describe a method of analysis to quantify recovery from hypersensitivity after surgery in rats with several distinct advantages over traditionally used methods. Study results do not support a sex difference in trajectory of recovery but confirm and extend previous observations that injury at the time of obstetric delivery is associated with an abnormally rapid recovery.

scholarly journals Expression and function of nesfatin-1 are altered by stage of the estrous cycle

2019 ◽  
Vol 317 (2) ◽  
pp. R328-R336 ◽  
Author(s):  
Alicia T. Pate ◽  
Abigayle L. Schnell ◽  
Teresa A. Ennis ◽  
Willis K. Samson ◽  
Gina L. C. Yosten
Keyword(s):  
Angiotensin Ii ◽  
Estrous Cycle ◽  
Sex Hormones ◽  
Cardiovascular Effects ◽  
Female Rats ◽  
Male Rats ◽  
Melanocortin Receptors ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
And Function

Nesfatin-1 is a peptide derived from the nucleobindin 2 ( Nucb2) precursor protein that has been shown to exert potent effects on appetite and cardiovascular function in male animals. Sex hormones modulate the expression of Nucb2 in several species, including goldfish, mouse, and rat, and human studies have revealed differential expression based on male or female sex. We therefore hypothesized that the ability of nesfatin-1 to increase mean arterial pressure (MAP) would be influenced by stage of the estrous cycle. Indeed, we found that in cycling female Sprague-Dawley rats, nesfatin-1 induced an increase in MAP on diestrus, when both estrogen and progesterone levels are low but not on proestrus or estrus. The effect of nesfatin-1 on MAP was dependent on functional central melanocortin receptors, because the nesfatin-1-induced increase in MAP was abolished by pretreatment with the melanocortin 3/4 receptor antagonist, SHU9119. We previously reported that nesfatin-1 inhibited angiotensin II-induced water drinking in male rats but found no effect of nesfatin-1 in females in diestrus. However, nesfatin-1 enhanced angiotensin II-induced elevations in MAP in females in diestrus but had no effect on males. Finally, in agreement with previous reports, the expression of Nucb2 mRNA in hypothalamus was significantly reduced in female rats in proestrus compared with rats in diestrus. From these data we conclude that the function and expression of nesfatin-1 are modulated by sex hormone status. Further studies are required to determine the contributions of chromosomal sex and individual sex hormones to the cardiovascular effects of nesfatin-1.

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