Intracerebral androgens and sexual behavior in the male rat

Johnston, P.

doi:10.1016/0018-506x(72)90024-4

Cited by 148 publications

(37 citation statements)

References 21 publications

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“…Furthermore, T or dlhydrotestosterone (DHT) implants into the MPOA of castrated animals produced a similar suppression in DA metabolism [205]. It is important to note, however, that DHT, the alpha-reduced metabolite of T, was ineffective in activating male sexual behavior in castrated rats when implanted into the MPOA [125]. The factor(s) underlying these diametrically opposed results is (are) not apparent.…”

Section: Interaction Of Da and Testicular Hormonesmentioning

confidence: 99%

Pharmacological analysis of male rat sexual behavior

Bitran

Hull

1987

Neuroscience & Biobehavioral Reviews

409

155

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Section: Interaction Of Da and Testicular Hormonesmentioning

confidence: 99%

Pharmacological analysis of male rat sexual behavior

Bitran

Hull

1987

Neuroscience & Biobehavioral Reviews

409

155

View full text Add to dashboard Cite

“…This area is rich in aromatase enzyme activity (AA) as well as receptors for both androgen and estrogen [2][3][4][5]. When implants of either estradiol or testosterone are placed in the POA, castrated rats are stimulated to copulate [6][7][8][9][10], Moreover, concurrent treatment with an aromatase inhibitor blocks the increase in mounting induced by intracranial testosterone infusion without affecting mounting activated by estradiol treatment [II],The aromatase enzyme complex in brain dissections encom passing both the hypothalamus and POA of rats is regulated by androgens [12]. Both testosterone and the nonaromatizable anReceived: April 17, 1990 Accepted after revision: June 22, 1990 drogen dihydrotestosterone (DHT) stimulate AA.…”

mentioning

confidence: 99%

Synergistic Induction of Aromatase Activity in the Rat Brain by Estradiol and 5α-Dihydrotestosterone

Roselli

1991

Neuroendocrinology

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Estrogens are produced locally from androgen precursors by cells within the hypothalamus and preoptic area (POA). The activity of the aromatase enzyme complex responsible for this intracellular conversion is controlled by gonadal steroids. The purpose of this study was to determine: whether estrogen acts together with androgen to regulate aromatase activity (AA) and whether nuclear androgen receptor levels are increased after exposure to combined treatment with estradiol benzoate (EB) and dihydrotestosterone (DHT). Thus, adult male rats were castrated and treated for 1 week with either vehicle (0.1 ml sesame oil, s.c), EB (2 µg/day), testosterone (3-cm Silastic implant), DHT (3-cm Silastic implant) or EB + DHT. These treatments produced hormone levels in the physiologic range. We found that both testosterone and DHT significantly stimulated AA (p < 0.05 vs. castrated rats). However, testosterone induced AA significantly more than DHT in the POA (p < 0.05; castrated + testosterone vs. castrated + DHT). EB alone did not affect AA but synergized with DHT to stimulate AA in the POA to levels equivalent with the testosterone-treated group. By comparison, EB alone did not enhance the induction of AA by DHT in the hypothalamus. Combined treatment with EB and DHT had no effect on the concentrations of nuclear androgen receptors in either tissue suggesting that the effect of EB was not mediated through an androgen receptor mechanism. These results suggest that both androgens and estrogens play a physiologic role in the control of estrogen formation in the rat brain. Furthermore, the anatomical specificity that we observed indicates that critical differences in enzyme responsiveness are present in different areas of the brain.

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“…The results of lesion and androgen-implant studies support the view that at least one functional con comitant of this binding capacity is the regula tion of masculine sexual behavior. For exam ple, ablation of or damage to the AHPOA abolishes or decreases masculine sexual per formance [guinea pigs: Brook hart and Dey, 1941;rats: Heimer and Larsson, 1966/67;cats: Hart et al, 1973;dogs: Hart, 1974;and fowl: Barfield, 1965], whereas implantation of testosterone (T) or its propionate (TP) directly into this and neighboring hypothalamic re gions restores copulatory behavior in cas trated males [rats: Dorner et al, 1968;Li.sk, 1967;Johnston and Davidson, 1972;ringdoves: Barfield, 1971;fowl: Barfield, 1969]. These findings, taken together, imply that the inte grity of these steroid target regions is critical for the performance of masculine copulatory behavior.…”

mentioning

confidence: 99%

Activation of Masculine Sexual Behavior by Intracranial Estradiol Benzoate Implants in Male Rats

1979

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Intracranial implants of estradiol benzoate (EB) were used to explore sites of action for the activation of masculine copulatory behavior in castrated male rats. In experiment 1, 27 or 30 gauge implants were placed unilaterally throughout the hypothalamus and preoptic area. Dihydrotestosterone (DHT) was administered subcutaneously (s.c.) to each male. 25 of 42 males with EB implants located in the medial anterior hypothalamic-preoptic area (AHPOA) exhibited ejaculatory patterns on at least 40% of the post-implantation tests. In contrast, only 4 of 18 of the males with implants located posterior to the anterior hypothalamic area displayed this level of response. This difference in the proportion of animals responding for each implant group was statistically significant. Seminal vesicle weights were not correlated with the occurrence of copulation. In experiment 2, either EB-filled or empty cannulae were placed unilaterally in the AHPOA. Half of the males of each group also received DHT s.c. Intracranial EB in conjunction with DHT s.c. resulted in a significantly greater frequency of ejaculatory response than any other treatment. Despite significant differences among the groups in seminal vesicle weights, there was no correlation with occurrence of ejaculatory behavior. These results are consistent with the hypothesis that testosterone (T) exerts its effects upon masculine sexual behavior via conversion to estradiol (E₂); and that the principal neural site of action is the AHPOA.

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Intracerebral androgens and sexual behavior in the male rat

Cited by 148 publications

References 21 publications

Pharmacological analysis of male rat sexual behavior

Pharmacological analysis of male rat sexual behavior

Synergistic Induction of Aromatase Activity in the Rat Brain by Estradiol and 5α-Dihydrotestosterone

Activation of Masculine Sexual Behavior by Intracranial Estradiol Benzoate Implants in Male Rats

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