Le sexage d'embryons bovins par la technique de l'amplification en chaîne par la polymérase (acp) d'une séquence Y-spécifique bovine

in Annales de Médecine Vétérinaire (1992), 136

Le sexisme bienveillant comme processus de maintien des inégalités sociales entre les genres

in Année Psychologique (L') (2012), 112

L’idée que le sexisme puisse s’exprimer sous forme de bienveillance peut paraître surprenante. En effet, la représentation que nous avons habituellement d’une personne sexiste est celle d’un homme aux ... [more ▼]

L’idée que le sexisme puisse s’exprimer sous forme de bienveillance peut paraître surprenante. En effet, la représentation que nous avons habituellement d’une personne sexiste est celle d’un homme aux attitudes clairement hostiles à l’égard des femmes. Le but de cette revue de littérature est de mettre en évidence une forme plus subtile de sexisme, le sexisme bienveillant, qui renvoie à des attitudes sexistes subjectivement positives, teintées de galanterie et de condescendance. Plus précisément, ce travail insiste sur la nécessité de prendre en compte cette forme insidieuse de sexisme dans la compréhension des relations entre les genres et de la considérer comme un véritable processus de maintien des inégalités sociales entre les hommes et les femmes. [less ▲]

Sexual abuse: is regression in borderline functioning a risk factor for acting out within the interfamilial system?

Poster (2012, May 11)

Sexual and social behaviour of Oreochromis aureus (Pisces : Cichlidae) : endocrine profiles.

in Belgian Journal of Zoology (1992), 122(2), 251

Sexual behavior activates the expression of the immediate early genes c-fos and Zenk (EGR-1) in catecholaminergic neurons of male Japanese quail

in Neuroscience (2005), 131(1), 13-30

We analyzed the expression of the immediate early genes c-fos and Zenk (egr-1) in the brain of male quail that were gonadally intact (1) or castrated and treated (CX+T) or not (CX) with testosterone and ... [more ▼]

We analyzed the expression of the immediate early genes c-fos and Zenk (egr-1) in the brain of male quail that were gonadally intact (1) or castrated and treated (CX+T) or not (CX) with testosterone and had been exposed for 60 min either to a sexually mature female (F), or to an empty arena (EA) or were left in their home cage (HC). Alternate sections in the brains collected 90 min after the start of behavioral interactions were stained by immunocytochemistry for the proteins FOS or ZENK alone or in association with tyrosine hydroxylase (TH), a marker of catecholaminergic neurons. C-fos and Zenk expression was statistically increased in six brain areas of sexually active birds (I+F, CX+T+F) compared with controls (CX+F, CX+T+EA, CX+T+HC), i.e. the preoptic area, bed nucleus striae terminalis, arcopallium, nucleus intercollicularis, periaqueductal gray and the ventral tegmental area. Interestingly, c-fos and Zenk expression was high in the nucleus intercollicularis, a midbrain vocal control nucleus, of I+F and CX+T+F birds that displayed copulatory behavior but emitted few crows but not in the nucleus intercollicularis of CX+T+EA birds that crowed frequently. Increases in c-fos expression were observed in TH-immunoreactive cells in the periaqueductal gray and ventral tegmental area, but not in the substantia nigra, of I+F and CX+T+F birds indicating the activation of dopaminergic neurons during sexual behavior. Together, these data confirm the implication of the steroid-sensitive preoptic area and bed nucleus striae terminalis in the control of copulation and support the notion that dopamine is involved in its control. (C) 2005 IBRO. Published by Elsevier Ltd. All rights reserved. [less ▲]

Sexual Behavior activity tracks rapid changes in brain estrogen concentrations

in Journal of Neuroscience (2007), 27(24), 6563-6572

Estrogens are classically viewed as hormones that bind to intracellular receptors, which then act as transcription factors to modulate gene expression; however, they also affect many aspects of neuronal ... [more ▼]

Estrogens are classically viewed as hormones that bind to intracellular receptors, which then act as transcription factors to modulate gene expression; however, they also affect many aspects of neuronal functioning by rapid nongenomic actions. Brain estrogen production can be regulated within minutes by changes in aromatase (estrogen synthase) activity as a result of calcium-dependent phosphorylations of the enzyme. To determine the effects of rapid changes in estrogen availability on male copulatory behavior, we mimicked in male mice the rapid upregulation and downregulation of brain estrogen concentration that should occur after inactivation or activation of aromatase activity. A single injection of different aromatase inhibitors [Vorozole, 1,4,6-androstatrien-3,17-dione (ATD), or its metabolite 17-OH-ATD (1,4,6-androstatrien-17beta-ol-3-one)] almost completely suppressed male sexual behavior (mounts and intromissions) expressed 10-20 min later by C57BL/6J mice but did not affect behavior in aromatase knock-out (ArKO) mice, activated by daily injections of estradiol benzoate, thereby confirming the specificity of the behavioral inhibition observed in wild-type mice. The rapid ATD-induced inhibition was reversed by the simultaneous injection of a large dose of estradiol. A single injection of estradiol to ArKO mice also activated male sexual behavior within 15 min. Thus, rapid increases or decreases in brain estrogen concentrations are followed within minutes by corresponding changes in male sexual behavior. Sexual behavior can thus be used to monitor changes in local estrogen concentrations and analyze the mechanisms mediating the rapid decline in estrogen signaling that takes place after inhibition of estrogen synthesis. [less ▲]

Sexual compatibility between two heterochronic morphs in the Alpine newt, Triturus alpestris

in Animal Behaviour (2001), 62(3), 559-566

Paedomorphosis, in which individuals retain ancestral characteristics in the adult stage, is widespread in newts and salamanders and is suspected to play an important role in evolution. In some species ... [more ▼]

Paedomorphosis, in which individuals retain ancestral characteristics in the adult stage, is widespread in newts and salamanders and is suspected to play an important role in evolution. In some species, paedomorphosis is facultative with some individuals forgoing metamorphosis. Optimality models have been proposed to explain the maintenance of this polymorphism, but require the integration of reproductive patterns into the models. We investigated the frequencies of inbreeding and outbreeding in two syntopic heterochronic morphs of the Alpine newt. The two morphs are sexually compatible: encounters between and within morphs were equally successful in terms of spermatophore transfer. Behavioural observations were in agreement with the sexual compatibility observed. Nevertheless, paedomorphic males displayed to females less frequently than metamorphic males. The two morphs differ largely on the basis of sexual secondary characteristics, but the majority of these traits did not affect mating success. Because of the large flow of genes between the two heterochronic morphs and because of the absence of spatial and temporal isolation, these results do not support sympatric speciation models, but are in favour of the maintenance of polymorphism in natural populations. (C) 2001 The Association for the Study of Animal Behaviour. [less ▲]

Sexual Differentiation in Quail: Critical Period and Hormonal Specificity

in Hormones & Behavior (1989), 23(1), 130-49

There is a discrepancy between results showing that male quail are demasculinized by exogenous estrogens only if the treatment is given before Day 12 of egg incubation and results showing that ovariectomy ... [more ▼]

There is a discrepancy between results showing that male quail are demasculinized by exogenous estrogens only if the treatment is given before Day 12 of egg incubation and results showing that ovariectomy of females after hatching still affects their sexual differentiation which leads to the conclusion that female demasculinization by ovarian estrogens is a continuing process extending into posthatching life. The first experiment was performed to test different models which have been proposed to reconcile these apparently contradictory results. Male and female quail were treated with 0, 5, or 25 micrograms of estradiol benzoate (EB) on either Day 9 or Day 14 of embryonic life. Birds were castrated at the age of 4 days to avoid the confounding effects of postnatal gonadal hormones and were treated as adults with testosterone (T). Whereas EB-treatment demasculizined sexual behavior and cloacal gland growth of males when administered on Day 9, it was without effect on Day 14. This result confirms the presence of a "critical period" for sexual differentiation of behavior in embryonic life. However, the time course of sexual differentiation and the sensitivity to the demasculinizing actions of estrogens were not the same for different behavioral and morphological characteristics. Some dependent variables such as plasma levels of luteinizing hormone and crowing were still affected by the EB treatment on Day 14. These results show that the whole process of demasculinization is not retricted to the "critical period" ending on Day 12 of incubation. A second experiment was performed to determine if 5 beta-dihydrotestosterone (5 beta-DHT), a metabolite of testosterone, also exerts demasculinizing effects during embryonic life. A large dose of 5 beta-DHT (2 mg/egg) had no effects on behavior and morphology in males if administered on Day 9 of egg incubation. This suggests that 5 beta-DHT, which is a steroid devoid of behavioral effects in the adult bird, is also an inactive compound as far as sexual differentiation of the quail is concerned. The high 5 beta-reductase activity which was previously identified in the hypothalamus of the embryonic quail thus probably plays a protective role. By transforming testosterone into inactive nonaromatizable androgens, it prevents male embryos from being demasculinized by their endogenous testosterone acting through aromatization. [less ▲]

Sexual differentiation of odor and partner preference in the rat.

in Physiology & Behavior (1996), 60(2), 489-94

Previous studies have shown that adult male rats, in which brain estrogen formation was inhibited neonatally by SC administration of the aromatase inhibitor 1,4, 6-androstatriene-3,17-dione (ATD), show an ... [more ▼]

Previous studies have shown that adult male rats, in which brain estrogen formation was inhibited neonatally by SC administration of the aromatase inhibitor 1,4, 6-androstatriene-3,17-dione (ATD), show an altered sexual partner preference. When tested in a three-compartment box, such gonadally intact ATD males approach and mate both with the estrous female and the sexually active male, whereas normal males prefer to approach and mate with the estrous female, avoiding the stimulus male. After castration in adulthood and estradiol treatment, ATD males prefer sexually active males. Similarly treated normal males prefer estrous females, and estrous females prefer to mate with males. In the present study, we asked what stimulus characteristics of active males vs. estrous females determined the different sexual preferences of males, ATD males, and of females. Were they chemosensory cues or more distal cues such as actually seeing and hearing the stimulus animals or the reward of sexual activity with the stimulus animals? Sex differences in preference were evident when animals were given a choice between soiled bedding from estrous females and from sexually active males. ATD and control males spent significantly more time on soiled bedding from estrous females than on soiled bedding from sexually active males. Control females spent significantly more time on soiled bedding from sexually active males than on soiled bedding from estrous females. More distal cues, such as seeing and hearing the stimulus animals, revealed differences in preference between control males and females, but not between ATD and control males. Physical interaction with the stimulus animals was a prerequisite for revealing differences in preference between ATD and control males. Then, the behavior of ATD males was clearly intermediate between that of normal male and female rats. In conclusion, neonatal estradiol is important for the psychosexual development of the male rat. However, the present data suggest that the psychosexual development of the male rat also requires either prenatal estradiol or perinatal testosterone. [less ▲]

Sexual differentiation of the neuroendocrine mechanisms regulating mate recognition in mammals

in Journal of Neuroendocrinology (2003), 15(6), 615-621

When in breeding condition, male and female mammals seek out and mate with opposite-sex conspecifics. The neural mechanisms controlling mate recognition and heterosexual partner preference are sexually ... [more ▼]

When in breeding condition, male and female mammals seek out and mate with opposite-sex conspecifics. The neural mechanisms controlling mate recognition and heterosexual partner preference are sexually differentiated by the perinatal actions of sex steroid hormones. Many mammalian species use odours to identify potential mates. Thus, sex differences in partner preference may actually reflect sex differences in how male and female mammals perceive socially relevant odours. Two olfactory systems have evolved in vertebrates that differ considerably in their anatomy and function. It is generally believed that the main olfactory system is used to detect a wide variety of volatile odours derived from food prey among many sources, whereas the accessory olfactory system has evolved to detect and process primarily nonvolatile odours shown to influence reproductive behaviours and neuroendocrine functions. Some recent results obtained in oestradiol-deficient aromatase knockout (ArKO) mice that provide evidence for a developmental role of oestradiol in olfactory investigation of volatile body odours are discussed, suggesting that: (i) oestrogens contribute to the development of the main olfactory system and (ii) mate recognition is mediated by the main as opposed to the accessory olfactory system. Thus, sex differences in mate recognition and sexual partner preference may reflect sex differences in the perception of odours by the main olfactory system. [less ▲]