Distribution and steroid dependence of aromatase enzyme immunoreactivity in limbic nuclei of the female musk shrew brain

Dellovade, Tammy L.; Harada, Nobuhiro; Rissman, Emilie F.

doi:10.1016/0006-8993(94)90267-4

Cited by 11 publications

(4 citation statements)

References 45 publications

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“…This study, however, still failed to detect immunoreactive cells in several brains regions such as the medial preoptic area, the medial amygdala, and the ventromedial nucleus of the hypothalamus, which were previously shown to contain high levels of aromatase activity (19,40). A similar distribution of ARO-ir cells has also been reported in the female musk shrew (Suncus murinus) (41).…”

Section: Distribution Of Aromatase Immunoreactivity In the Rodent Limsupporting

confidence: 44%

Estrogen Synthetase (Aromatase) Immunohistochemistry Reveals Concordance Between Avian and Rodent Limbic Systems and Hypothalami

Naftolin

Horváth

Balthazart

2001

Exp Biol Med (Maywood)

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During amniote evolution, an early divergence occurred about 300 million years ago between the reptilian lines leading to the appearance of birds (anapsids) and mammals (synapsids). The different functional requirements of these vertebrate groups have Involved divergent evolution of their brains. Even superficial examination reveals major anatomical differences between mammalian and avian brains, such as extensive development of the optic lobes and cerebellum In birds and a highly developed cortex in mammals. It has been nearly impossible to identify avian homologs of some mammalian brain regions by standard morphological criteria. This has long frustrated efforts at clarifying hypotheses regarding the anatomical location, field size, and regulation of brain functions shared between these two classes, despite the certainty that the principles of neurobiology apply equally at the cellular level In both groups. In an effort to remove this barrier, we have sought markers of common function that despite apparent anatomical dissimilarity, can allow recognition of homologous brain structures. We illustrate here how comparative analysis of the distribution of the steroid-metabolizing enzyme estrogen synthetase (aromatase) may help to understand the differences and similarities in the limbic system and hypothalamus of birds and mammals.

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Section: Distribution Of Aromatase Immunoreactivity In the Rodent Limsupporting

confidence: 44%

Estrogen Synthetase (Aromatase) Immunohistochemistry Reveals Concordance Between Avian and Rodent Limbic Systems and Hypothalami

Naftolin

Horváth

Balthazart

2001

Exp Biol Med (Maywood)

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“…With immunohistochemical techniques, the presence of aromatase has been demonstrated in several nerve centers (Shinoda et al 1989(Shinoda et al , 1990Balthazart et al 1990Balthazart et al , 1991Sanghera et al 1991;Segovia and Guillamón 1993;Dellovade et al 1994;Tsuruo et al 1994;Yamada et al 1994;Foidart et al 1995). In particular, the enzyme has been described in the dorsal area, in the medial preoptic area, and in the paraventricular and ventromedial nuclei of the hypothalamus (Foidart et al 1994(Foidart et al , 1995.…”

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confidence: 97%

Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis

Carretero¹,

Vázquez²,

Blanco³

et al. 1999

Cell and Tissue Research

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In order to analyze whether aromatase is present in the hypophysis of adult rats, we have performed an immunohistochemical study in young adult male and female rats. Our study has revealed that the hypophysis of adult rats contains aromatase, although marked differences are found between the sexes. The hypophyses of male rats have cells immunoreactive for the enzyme, 34.40% of these hypophyseal cells showing reaction. By contrast, cells from female rats show very little reaction, only 0.84% of them being reactive. No significant differences in the percentage of immunoreactive cells between one phase and another are observed during the estrous cycle. Our results point to the immunohistochemical expression of aromatase in the hypophysis of adult rats and at the same time suggest that its expression is sex-dependent. The enzyme may therefore be involved in the regulation of adenohypophyseal cytology by androgens.

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“…But aromatase irnrnunoreactivity is either not present (43; Rissman unpublished data) or present in scant fibers in the POA (42). In the musk shrew aromatase enzyme immunoreactivity is present in the BST, one region where TP implants were effective, but it is absent in the POA and the VMN (44).…”

Section: Discussionmentioning

confidence: 99%

Testosterone Implants in Specific Neural Sites Activate Female Sexual Behaviour

Sharma

Rissman

1994

J Neuroendocrinology

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Sexual behaviour in most female mammals is regulated by oestrogen, often acting synergistically with progesterone. Moreover, the most important neural site of action for oestradiol is the ventromedial nucleus. In the female musk shrew, Suncus murinus, testosterone (T) activates sexual behaviour. Virgin females first engage in copulatory behaviour many hours in advance of follicular development and ovulation, when plasma oestradiol levels are very low. Testosterone, produced by the ovaries and the adrenal glands, must be aromatized centrally to oestradiol to initiate sexual behaviour. To identify the neural sites of action for T, ovariectomized females received unilateral hormone implants containing testosterone propionate. Hormone pellets were placed in 1 of several brain sites including the medial preoptic area and the dorsalmedial hypothalamus (DMH). Implants in either of these 2 sites, but not in the lateral preoptic area, internal capsule, nor anterior hypothalamus stimulated the induction of sexual behaviour. Hormone implants in the ventrolateral hypothalamus resulted in partially receptive animals. Immunocytochemistry was employed to determine which steroid receptors were present in the 2 behaviourally active sites. The medial preoptic area (MPO) and the dorsal and ventromedial hypothalamus both contain many cells that express oestrogen receptor immunoreactivity. A smaller subset of neurons in these regions are immunoreactive for androgen receptors. In summary, testosterone can act specifically in either the MPO or the DMH to induce female sexual behaviour. Both sites contain cells that express oestrogen and androgen receptors. Thus, testosterone may work via one or both of these steroid receptors to regulate behaviour.(ABSTRACT TRUNCATED AT 250 WORDS)

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Distribution and steroid dependence of aromatase enzyme immunoreactivity in limbic nuclei of the female musk shrew brain

Cited by 11 publications

References 45 publications

Estrogen Synthetase (Aromatase) Immunohistochemistry Reveals Concordance Between Avian and Rodent Limbic Systems and Hypothalami

Estrogen Synthetase (Aromatase) Immunohistochemistry Reveals Concordance Between Avian and Rodent Limbic Systems and Hypothalami

Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis

Testosterone Implants in Specific Neural Sites Activate Female Sexual Behaviour

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