Details

Autor(en) / Beteiligte

• Pluchino, Nicola
• Ninni, Filippo
• Casarosa, Elena
• Giannini, Andrea
• Merlini, Sara
• Cubeddu, Alessandra
• Luisi, Michele
• Cela, Vito
• Genazzani, Andrea Riccardo

Titel

Sex Differences in Brain and Plasma β-Endorphin Content following Testosterone, Dihydrotestosterone and Estradiol Administration to Gonadectomized Rats

Ist Teil von

• Neuroendocrinology, 2009-01, Vol.89 (4), p.411-423

Ort / Verlag

Basel, Switzerland: Karger

Erscheinungsjahr

2009

Quelle

MEDLINE

Beschreibungen/Notizen

• Aims: The present study aims at evaluating the effect of a 2-week treatment with testosterone (T), dihydrotestosterone (DHT) and estradiol valerate (E 2 V) 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). E 2 V 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 E 2 V significantly increased β-END concentration in all brain areas and in plasma. In the OCX group, T and E 2 V 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.