Sexual partner preference, hypothalamic morphology and aromatase in rams

ROSELLI, C; Larkin, Kelly L.; Schrunk, Jessica M.; Stormshak, F.

doi:10.1016/s0031-9384(04)00355-5

Cited by 5 publications

(6 citation statements)

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“…Reports indicate that ∼8% of domestic rams (i.e., male-oriented rams) prefer to approach and mount other rams as opposed to estrous ewes when given a simultaneous choice between these two alternatives [74]. We are currently studying male-oriented rams in order to understand the degree to which sexual partner preferences in this species are organized by prenatal estrogen exposure through the brain aromatization pathway.…”

Section: The Relationship Between the Ovine Sexually Dimorphic Nucleumentioning

confidence: 99%

Brain aromatase: Roles in reproduction and neuroprotection

ROSELLI

2007

The Journal of Steroid Biochemistry and Molecular Biology

110

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It is well established that aromatization constitutes an essential part of testosterone's signaling pathway in brain and that estrogen metabolites, often together with testosterone, organize and activate masculine neural circuits. This paper summarizes the current understanding regarding the distribution, regulation and function of brain aromatase in mammals. Data from our laboratory are presented that highlight the important function of aromatase in the regulation of androgen feedback sensitivity in non-human primates and the possible role that aromatase plays in determining the brain structure and sexual partner preferences of rams. In addition, new data is presented indicating that the capacity for aromatization in cortical astrocytes is associated with cell survival and may be important for neuroprotection. It is anticipated that a better appreciation of the physiological and pathophysiological functions of aromatase will lead to important clinical insights.

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Section: The Relationship Between the Ovine Sexually Dimorphic Nucleumentioning

confidence: 99%

Brain aromatase: Roles in reproduction and neuroprotection

ROSELLI

2007

The Journal of Steroid Biochemistry and Molecular Biology

110

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“…The conversion of androgens to estrogens by the enzyme aromatase cytochrome P450 (P450arom), which is expressed in the brain, has a central role in organizing neuroendocrine function [9] and a variety of reproductive and social behaviors [10]. For instance, P450arom expression in the preoptic area of the hypothalamus is higher in rams that prefer females to male sexual partners [11]. The sexually dimorphic expression of P450arom in the mammalian [12] and avian [13] brain provides additional support for the importance of the enzyme in these processes.…”

Section: Introductionmentioning

confidence: 99%

Porcine Hypothalamic Aromatase Cytochrome P450: Isoform Characterization, Sex-Dependent Activity, Regional Expression, and Regulation by Enzyme Inhibition in Neonatal Boars1

Corbin

Berger

Ford

et al. 2009

Biology of Reproduction

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Domestic pigs have three CYP19 genes encoding functional paralogues of the enzyme aromatase cytochrome P450 (P450arom) that are expressed in the gonads, placenta, and preimplantation blastocyst. All catalyze estrogen synthesis, but the gonadal-type enzyme is unique in also synthesizing a nonaromatizable biopotent testosterone metabolite, 1OH-testosterone (1OH-T). P450arom is expressed in the vertebrate brain, is higher in males than females, but has not been investigated in pigs, to our knowledge. Therefore, these studies defined which of the porcine CYP19 genes was expressed, and at what level, in adult male and female hypothalamus. Regional expression was examined in mature boars, and regulation of P450arom expression in neonatal boars was investigated by inhibition of P450arom with letrozole, which is known to reprogram testicular expression. Pig hypothalami expressed the gonadal form of P450arom (redesignated the "gonadal/hypothalamic" porcine CYP19 gene and paralogue) based on functional analysis confirmed by cloning and sequencing transcripts. Hypothalamic tissue synthesized 1OH-T and was sensitive to the selective P450arom inhibitor etomidate. Levels were 4-fold higher in male than female hypothalami, with expression in the medial preoptic area and lateral borders of the ventromedial hypothalamus of boars. In vivo, letrozole-treated neonates had increased aromatase activity in hypothalami but decreased activity in testes. Therefore, although the same CYP19 gene is expressed in both tissues, expression is regulated differently in the hypothalamus than testis. These investigations, the first such studies in pig brain to our knowledge, demonstrate unusual aspects of P450arom expression and regulation in the hypothalamus, offering promise of gaining better insight into roles of P450arom in reproductive function.

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“…Approximately 8–10% of domestic rams exhibit a sexual preference for other rams (i.e. male‐oriented rams) . These rams not only mount, but also direct all courtship activities (anal–genital smelling, kicks, nibbles) to other rams, whereas their sexual interest and activity towards females is extremely low or nonexistent.…”

Section: Steroid Hormones and Programmingmentioning

confidence: 99%

“…Also, there is evidence that the conversion of testosterone to oestradiol by the aromatase enzyme is required to masculinise the SDN‐POA . Much like in rats, sheep have a homologue of the SDN‐POA, called the ovine SDN (oSDN) that is twice as large in rams than in ewes . The oSDN comprises a dense cluster of cells comprising the central component of the medial preoptic nucleus that can be identified by Nissl staining and by abundant expression of aromatase mRNA.…”

Section: Steroid Hormones and Programmingmentioning

confidence: 99%

Developmental and Functional Effects of Steroid Hormones on the Neuroendocrine Axis and Spinal Cord

Zubeldía-Brenner

Roselli

Recabarren

et al. 2016

J Neuroendocrinology

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This review highlights the principal effects of steroid hormones at central and peripheral levels in the neuroendocrine axis. The data discussed here points out the principal role of estrogens and testosterone in hormonal programming in relation to sexual orientation, reproductive and metabolic programming, and in the neuroendocrine mechanism involved in development of polycystic ovary syndrome phenotype. Moreover, consistent with the wide range of processes in which steroid hormones take part, we discuss the protective effects of progesterone on neurodegenerative disease and the signaling mechanism involved in the genesis of estrogen-induced pituitary prolactinomas.

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Sexual partner preference, hypothalamic morphology and aromatase in rams

Cited by 5 publications

References 0 publications

Brain aromatase: Roles in reproduction and neuroprotection

Brain aromatase: Roles in reproduction and neuroprotection

Porcine Hypothalamic Aromatase Cytochrome P450: Isoform Characterization, Sex-Dependent Activity, Regional Expression, and Regulation by Enzyme Inhibition in Neonatal Boars1

Developmental and Functional Effects of Steroid Hormones on the Neuroendocrine Axis and Spinal Cord

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