Aims: The present study aims at evaluating the effect of a 2-week treatment with testosterone (T), dihydrotestosterone (DHT) and estradiol valerate (E 2V) on brain and plasma β-endorphin (β-END) concentrations in gonadectomized rats of both sexes. Methods: Eight groups of female and 8 groups of male Wistar rats were included. For each sex, 1 group of gonad-intact and 1 group of gonadectomized rats were employed as controls (placebo). The other groups received subcutaneous T at the doses of 10 and 100 μg/kg/day (female rats) or 1 and 5 mg/kg/day (male rats). Subcutaneous DHT was administered at the doses of 1, 10, 100 μg/kg/day (female rats) or 0.1, 1 and 5 mg/kg/day (male rats). E2V was administered subcutaneously at 0.05 mg/kg/day. β-END levels were measured in different brain areas and plasma. Results: Ovariectomy (OVX) induced a significant decrease in β-END in all brain areas analyzed as well as in plasma. Orchidectomy (OCX) reduced opioid concentration in the hypothalamus, anterior pituitary and neurointermediate lobe. In OVX rats, T replacement as well as E2V significantly increased β-END concentration in all brain areas and in plasma. In the OCX group, T and E2V did not influence β-END concentrations in different hypothalamic areas. However, they produced a significant rise in β-END levels in the hypothalamus, neurointermediate lobe, anterior pituitary and plasma. Conversely, DHT replacement did not affect β-END levels at any dose administered, either in males or females. Conclusions: The sensitivity of the endogenous opiatergic system to T administration seems to be sex-related. This effect is particularly evident in the brains of female animals where this endogenous endorphin elicits a much greater response than it does in males that have undergone gonadal steroid depletion and subsequent T replacement. Copyright © 2009 S. Karger AG, Basel.

Sex differences in brain and plasma β-endorphin content following testosterone, dihydrotestosterone and estradiol administration to gonadectomized rats

Casarosa, Elena
Data Curation
;
Giannini, Andrea
Writing – Original Draft Preparation
;
Cubeddu, Alessandra
Investigation
;
2009-01-01

Abstract

Aims: The present study aims at evaluating the effect of a 2-week treatment with testosterone (T), dihydrotestosterone (DHT) and estradiol valerate (E 2V) on brain and plasma β-endorphin (β-END) concentrations in gonadectomized rats of both sexes. Methods: Eight groups of female and 8 groups of male Wistar rats were included. For each sex, 1 group of gonad-intact and 1 group of gonadectomized rats were employed as controls (placebo). The other groups received subcutaneous T at the doses of 10 and 100 μg/kg/day (female rats) or 1 and 5 mg/kg/day (male rats). Subcutaneous DHT was administered at the doses of 1, 10, 100 μg/kg/day (female rats) or 0.1, 1 and 5 mg/kg/day (male rats). E2V was administered subcutaneously at 0.05 mg/kg/day. β-END levels were measured in different brain areas and plasma. Results: Ovariectomy (OVX) induced a significant decrease in β-END in all brain areas analyzed as well as in plasma. Orchidectomy (OCX) reduced opioid concentration in the hypothalamus, anterior pituitary and neurointermediate lobe. In OVX rats, T replacement as well as E2V significantly increased β-END concentration in all brain areas and in plasma. In the OCX group, T and E2V did not influence β-END concentrations in different hypothalamic areas. However, they produced a significant rise in β-END levels in the hypothalamus, neurointermediate lobe, anterior pituitary and plasma. Conversely, DHT replacement did not affect β-END levels at any dose administered, either in males or females. Conclusions: The sensitivity of the endogenous opiatergic system to T administration seems to be sex-related. This effect is particularly evident in the brains of female animals where this endogenous endorphin elicits a much greater response than it does in males that have undergone gonadal steroid depletion and subsequent T replacement. Copyright © 2009 S. Karger AG, Basel.
2009
Pluchino, Nicola; Ninni, Filippo; Casarosa, Elena; Giannini, Andrea; Merlini, Sara; Cubeddu, Alessandra; Luisi, Michele; Cela, Vito; Genazzani, Andrea Riccardo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/987383
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