Androgen Metabolism in the Brain: Role in Sexual Differentiation and in the Control of Gonadotropin Secretion

Author(s):  
P. Negri-Cesi ◽  
F. Celotti ◽  
L. Martini
2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Jordyn M. Stuart ◽  
Jason J. Paris ◽  
Cheryl Frye ◽  
Heather B. Bradshaw

Background. Endogenous cannabinoids (eCBs) are involved in the development and regulation of reproductive behaviors. Likewise, prostaglandins (PGs) drive sexual differentiation and initiation of ovulation. Here, we use lipidomics strategies to test the hypotheses that mating immediately activates the biosynthesis and/or metabolism of eCBs and PGs and that specific mating strategies differentially regulate these lipids in the brain.Methods. Lipid extractions and tandem mass spectrometric analysis were performed on brains from proestrous rats that had experienced one of two mating strategies (paced or standard mating) and two nonmated groups (chamber exposed and home cage controls). Levels of PGs (PGE2 and PGF2alpha), eCBs (AEA and 2-AG,N-arachidonoyl glycine), and 4 related lipids (4N-acylethanolamides) were measured in olfactory bulb, hypothalamus, hippocampus, thalamus, striatum, midbrain, cerebellum, and brainstem.Results. Overall, levels of these lipids were significantly lower among paced compared to standard mated rats with the most dramatic decreases observed in brainstem, hippocampus, midbrain, and striatum. However, chamber exposed rats had significantly higher levels of these lipids compared to home cage controls and paced mated wherein the hippocampus showed the largest increases.Conclusions. These data demonstrate that mating strategies and exposure to mating arenas influence lipid signaling in the brain.


2016 ◽  
Vol 371 (1688) ◽  
pp. 20150114 ◽  
Author(s):  
Nancy G. Forger

Circumstantial evidence alone argues that the establishment and maintenance of sex differences in the brain depend on epigenetic modifications of chromatin structure. More direct evidence has recently been obtained from two types of studies: those manipulating a particular epigenetic mechanism, and those examining the genome-wide distribution of specific epigenetic marks. The manipulation of histone acetylation or DNA methylation disrupts the development of several neural sex differences in rodents. Taken together, however, the evidence suggests there is unlikely to be a simple formula for masculine or feminine development of the brain and behaviour; instead, underlying epigenetic mechanisms may vary by brain region or even by dependent variable within a region. Whole-genome studies related to sex differences in the brain have only very recently been reported, but suggest that males and females may use different combinations of epigenetic modifications to control gene expression, even in cases where gene expression does not differ between the sexes. Finally, recent findings are discussed that are likely to direct future studies on the role of epigenetic mechanisms in sexual differentiation of the brain and behaviour.


Human Growth ◽  
1979 ◽  
pp. 183-221
Author(s):  
Pamela C. B. Mackinnon

2015 ◽  
Vol 226 (2) ◽  
pp. T1-T11 ◽  
Author(s):  
Geoffrey Raisman

Geoffrey Harris is chiefly known for his demonstration of the control of the pituitary gland by the portal vessels coming from the hypothalamus. This does not do justice to his extraordinary contribution to biology. Harris' life's work was central in demonstrating the brain/body interactions by which animals and humans adapt to their environment, and above all the control of that most crucial and proximate of all evolutionary events – reproduction. In this brief review, I have tried to put Geoffrey Harris' work in the context of the scientific thinking at the time when he began his work, and above all, the contribution of his mentor, FHA Marshall, on whose towering shoulders Harris rose. But this is mainly my personal story, in which I have tried to show the debt that my work owed to Harris and especially to my dear friend, the late Keith Brown-Grant in Harris' team. I myself was never an endocrinologist, but over a short period in the early 1970s, under the influence of such inspirational mentors, and using purely anatomical methods, I was able to demonstrate sexual dimorphism and hormone-dependent sexual differentiation in the connections of the preoptic area, regeneration of the median eminence, the ultrastructure of apoptosis, the requirement for the suprachiasmatic nuclei in reproductive rhythms, the existence of non-rod or cone photoreceptors in the albino rat retina and, later, the expression of vasopressin by solitary (one in 600) magnocellular neurons in the polydipsic di/di Brattleboro mutant rat; this phenomenon was subsequently shown to be due to a+1 reading frameshift. I end this brief overview by mentioning some of the abiding and fascinating mysteries of the endocrine memory of the brain that arise from Harris' work on the control of the endocrines, and by pointing out how the current interest in chronobiology emphasises what a Cinderella the endocrine mechanisms have become in current brain imaging studies.


1982 ◽  
Vol 5 (1) ◽  
pp. 1-61 ◽  
Author(s):  
Patrick J. Thomas ◽  
Mohsen Ani

2009 ◽  
pp. 1707-1746 ◽  
Author(s):  
M.M. McCarthy ◽  
G.J. de Vries ◽  
N.G. Forger

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