Gonadal Hormones and Sexual Differentiation of Human Behavior

Author(s):  
Melissa Hines
2010 ◽  
Vol 22 (4) ◽  
pp. 239-253 ◽  
Author(s):  
Gustavo Benavides

AbstractResearch on the emergence of the configuration known as “religion” requires tracing the articulation among biological, psychological and social processes. This research must take into account evolutionary approaches; first, in terms of hominid evolution, for it is only by taking into consideration work on symbolization, language development, the capacity to engage in metacognition and cooperation, the tendency to form hierarchies, engage in violence, sexual differentiation, and related topics, that one can hope to trace the emergence of certain relatively stable features of human behavior. But since symbolization and the other capacities mentioned above are exercised in specific social circumstances—which themselves could not have come into existence were it not for the exercise of those capacities—it is essential to consider social evolution, especially insofar as this evolution leads to the appearance of stratified societies and to the kind of labor that prevails in them.


2007 ◽  
Vol 292 (1) ◽  
pp. R586-R597 ◽  
Author(s):  
Daniel L. Hummer ◽  
Tammy J. Jechura ◽  
Megan M. Mahoney ◽  
Theresa M. Lee

The slowly maturing, long-lived rodent Octodon degus (degu) provides a unique opportunity to examine the development of the circadian system during adolescence. These studies characterize entrained and free-running activity rhythms in gonadally intact and prepubertally gonadectomized male and female degus across the first year of life to clarify the impact of sex and gonadal hormones on the circadian system during adolescence. Gonadally intact degus exhibited a delay in the phase angle of activity onset (Ψon) during puberty, which reversed as animals became reproductively competent. Gonadectomy before puberty prevented this phase delay. However, the effect of gonadal hormones during puberty on Ψon does not result from changes in the period of the underlying circadian pacemaker. A sex difference in Ψon and free-running period (τ) emerged several months after puberty; these developmental changes are not likely to be related, since the sex difference in Ψon emerged before the sex difference in τ. Changes in the levels of circulating hormones cannot explain the emergence of these sex differences, since there is a rather lengthy delay between the age at which degus reach sexual maturity and the age at which Ψon and τ become sexually dimorphic. However, postnatal exposure to gonadal hormones is required for sexual differentiation of Ψon and τ, since these sex differences were absent in prepubertally gonadectomized degus. These data suggest that gonadal hormones modulate the circadian system during adolescent development and provide a new model for postpubertal sexual differentiation of a central nervous system structure.


1985 ◽  
Vol 63 (6) ◽  
pp. 577-594 ◽  
Author(s):  
Roger A. Gorski

The mammalian brain appears to be inherently feminine and the action of testicular hormones during development is necessary for the differentiation of the masculine brain both in terms of functional potential and actual structure. Experimental evidence for this statement is reviewed in this discussion. Recent discoveries of marked structural sex differences in the central nervous system, such as the sexually dimorphic nucleus of the preoptic area in the rat, offer model systems to investigate potential mechanisms by which gonadal hormones permanently modify neuronal differentiation. Although effects of these steroids on neurogenesis and neuronal migration and specification have not been conclusively eliminated, it is currently believed, but not proven, that the principle mechanism of steroid action is to maintain neuronal survival during a period of neuronal death. The structural models of the sexual differentiation of the central nervous system also provide the opportunity to identify sex differences in neurochemical distribution. Two examples in the rat brain are presented: the distribution of serotonin-immunoreactive fibers in the medial preoptic nucleus and of tyrosine hydroxylase-immunoreactive fibers and cells in the anteroventral periventricular nucleus. It is likely that sexual dimorphisms will be found to be characteristic of many neural and neurochemical systems. The final section of this review raises the possibility that the brain of the adult may, in response to steroid action, be morphologically plastic, and considers briefly the likelihood that the brain of the human species is also influenced during development by the hormonal environment.


2017 ◽  
Vol 31 (4) ◽  
pp. 300-306 ◽  
Author(s):  
Maria Julia Cambiasso ◽  
Carla Daniela Cisternas ◽  
Isabel Ruiz-Palmero ◽  
Maria Julia Scerbo ◽  
Maria Angeles Arevalo ◽  
...  

1985 ◽  
Vol 109 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Rüdiger Schulz ◽  
Annemarie Wilhelm ◽  
Karl Martin Pirke ◽  
Albert Herz

Abstract. Previous studies in male and female immature rats have revealed striking sex differences as concerns endorphinergic and adrenergic control of luteinizing hormone (LH) secretion. The present study examines in 10 days old male and females rats whether these differences result from sexual differentiation of the brain, or acute effects of male and female gonadal hormones. The techniques employed to manipulate these mechanisms were gonadectomy immediately post-partum and androgenization. Androgenization on the 1st and 2nd day of life reduces the ability of naloxone to elevate serum LH levels in females, but failed to modify the LH-elevating effect of clonidine in males. Experiments with castrates showed that testosterone is critical for these sex-related differences. Treatment with testosterone on the 9th day of life of intact or gonadectomized rats revealed the ability of this hormone to modify LH-release acutely. We conclude that sexual differentiation of the brain may be of minor significance for the sex-related LH-control mechanisms in prepubertal rats. Of importance is the acute presence of testosterone, since in its absence male characteristics disappear.


2011 ◽  
Vol 301 (3) ◽  
pp. R561-R571 ◽  
Author(s):  
Monte E. Turner ◽  
Daniel Ely ◽  
Jeremy Prokop ◽  
Amy Milsted

The Sry locus on the mammalian Y chromosome is the developmental switch responsible for testis determination. Inconsistent with this important function, the Sry locus is transcribed in adult males at times and in tissues not involved with testis determination. Sry is expressed in multiple tissues of the peripheral and central nervous system. Sry is derived from Sox3 and is similar to other SOXB family loci. The SOXB loci are responsible for nervous system development. Sry has been demonstrated to modulate the catecholamine pathway, so it should have functional consequences in the central and peripheral nervous system. The nervous system expression and potential function are consistent with Sry as a SOXB family member. In mammals, Sox3 is X-linked and undergoes dosage compensation in females. The expression of Sry in adult males allows for a type of sexual differentiation independent of circulating gonadal hormones. A quantitative difference in Sox3 plus Sry expression in males vs. females could drive changes in the transcriptome of these cells, differentiating male and female cells. Sry expression and its transcriptional effects should be considered when investigating sexual dimorphic phenotypes.


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