Distribution of Two Isozymes of 5α-Reductase in the Brains of Adult Male and Female Green Anole Lizards

Cohen, Rachel E.; Wade, Juli

doi:10.1159/000322096

Cited by 15 publications

(26 citation statements)

References 95 publications

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“…5a-Reductase I mRNA is detected only in the brainstem, whereas 5a-reductase II is detected in discrete regions throughout the brain. Parallel to the lack of effect of DHT in activating masculine behaviour [68], the number of 5a-reductase II expressing cells is equivalent across the sexes and seasons in the POA and AMY [81].…”

Section: Lizardsmentioning

confidence: 94%

Genetic regulation of sex differences in songbirds and lizards

Wade

2016

Phil. Trans. R. Soc. B

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One contribution of 16 to a theme issue 'Multifaceted origins of sex differences in the brain'. Sex differences in the morphology of neural and peripheral structures related to reproduction often parallel the frequency of particular behaviours displayed by males and females. In a variety of model organisms, these sex differences are organized in development by gonadal steroids, which also act in adulthood to modulate behavioural expression and in some cases to generate parallel anatomical changes on a seasonal basis. Data collected from diverse species, however, suggest that changes in hormone availability are not sufficient to explain sex and seasonal differences in structure and function. This paper pulls together some of this literature from songbirds and lizards and considers the information in the broader context of taking a comparative approach to investigating genetic mechanisms associated with behavioural neuroendocrinology.

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Section: Lizardsmentioning

confidence: 94%

Genetic regulation of sex differences in songbirds and lizards

Wade

2016

Phil. Trans. R. Soc. B

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“…Both aromatase (GenBank ID: XM_003225883) and 5αR2 (GenBank ID: XM_003215965.1) were cloned previously [10; 12]. Briefly, sense (T7 for aromatase and SP6 for 5αR2) and antisense (T3 for aromatase and T7 for 5αR2) probes were transcribed using the Digoxigenin RNA Labeling Kit per manufacturer’s instructions (Roche Diagnostics; Indianapolis, IN).…”

Section: Methodsmentioning

confidence: 99%

“…The slides were examined under brightfield illumination using Stereo Investigator software (MicroBrightfield, Inc.; Williston, VT) as in Cohen and Wade [10; 12] by a user blind to experimental group. Estimates of total counts of cells positive for aromatase or 5αR2 were obtained using the Optical Fractionator function.…”

Section: Methodsmentioning

confidence: 99%

“…Unlike in mammals, 5αR1 is not expressed in the forebrain of green anoles, although expression in specific brainstem nuclei is clear. In contrast, 5αR2 mRNA is detected in specific regions throughout the brain; the density of these cells in the AMY is greater in females than in males [10]. …”

Section: Introductionmentioning

confidence: 99%

“…Because we previously documented seasonal effects of T on aromatase activity (see above), we also examined these enzymes across seasons. As we had done in intact animals [10; 12], in situ hybridization was used to evaluate the numbers and densities of mRNA-containing cells in the POA, AMY and VMH of male and female green anoles from both the BS and NBS.…”

Section: Introductionmentioning

confidence: 99%

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Aromatase and 5α-reductase type 2 mRNA in the green anole forebrain: An investigation of the effects of sex, season and testosterone manipulation

Cohen

Wade

2012

General and Comparative Endocrinology

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Aromatase and 5α-reductase (5αR) catalyze the synthesis of testosterone (T) metabolites: estradiol and 5α-dihydrotestosterone, respectively. These enzymes are important in controlling sexual behaviors in male and female vertebrates. To investigate factors contributing to their regulation in reptiles, male and female green anole lizards were gonadectomized during the breeding and non-breeding seasons and treated with a T-filled or blank capsule. In situ hybridization was used to examine main effects of and interactions among sex, season, and T on expression of aromatase and one isozyme of 5αR (5αR2) in three brain regions that control reproductive behaviors: the preoptic area, ventromedial nucleus of the amygdala and ventromedial hypothalamus (VMH). Patterns of mRNA generally paralleled previous evaluations of intact animals. Although no main effects of T were detected, interactions were present in the VMH. Specifically, the density of 5αR2 expressing cells was greater in T-treated than control females in this region, regardless of season. Among breeding males, blank-treated males had a denser population of 5αR2 positive cells than T-treated males. Overall, T appears to have less of a role in the regulation of these enzymes than in other vertebrate groups, which is consistent with the primary role of T (rather than its metabolites) in regulation of reproductive behaviors in lizards. However, further investigation of protein and enzyme activity levels are needed before specific conclusions can be drawn.

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Neural control of reproduction in reptiles

Shankey,

Cohen

2024

J Exp Zool Pt A

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Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well‐documented across vertebrates. The conversion of T into E2 and 5α‐dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research.

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Distribution of Two Isozymes of 5α-Reductase in the Brains of Adult Male and Female Green Anole Lizards

Cited by 15 publications

References 95 publications

Genetic regulation of sex differences in songbirds and lizards

Genetic regulation of sex differences in songbirds and lizards

Aromatase and 5α-reductase type 2 mRNA in the green anole forebrain: An investigation of the effects of sex, season and testosterone manipulation

Neural control of reproduction in reptiles

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