Yie S M, Brown G M
Department of Biomedical Sciences, McMaster University, Hamilton, Canada.
Neuroendocrinology. 1995 Jul;62(1):93-100. doi: 10.1159/000126993.
Several studies have shown sex hormone effects on pineal function. In order to clarify the role of adrenergic mechanisms in these effects, we investigated the pineal response to adrenergic stimulation and pineal beta-adrenergic receptors following castration and/or sex hormone treatment in 2-month-old male and female Sprague-Dawley rats. The urinary 6-sulphatoxymelatonin (aMT6s) response to isoproterenol (ISO) was compared in castrated and sham-operated animals. Ovariectomy caused an increase and orchiectomy a decrease in ISO-induced urinary aMT6s excretion. The melatonin response to ISO was examined in pineal glands and serum samples obtained from castrated, sex-hormone-treated castrated and sham-operated rats. Consistently, ovariectomy increased pineal and serum melatonin responses to ISO, while orchiectomy decreased the responses; oestradiol and testosterone treatments, respectively, reversed these effects. 3H-dihydroalprenolol binding was measured in single pineal glands from castrated, sex-hormone-treated castrated and sham-operated rats. Ovariectomy increased the density of beta-adrenoceptors, whereas orchiectomy decreased the density; oestradiol and testosterone replacement, respectively, blocked these effects. No significant effect on receptor Kd values was found. These data suggest that sex hormones regulate pineal melatonin production by modifying beta-adrenergic mechanisms.
多项研究表明性激素对松果体功能有影响。为了阐明肾上腺素能机制在这些影响中的作用，我们研究了2月龄雄性和雌性斯普拉格-道利大鼠去势和/或性激素处理后松果体对肾上腺素能刺激的反应以及松果体β-肾上腺素能受体。比较了去势和假手术动物对异丙肾上腺素（ISO）的尿6-硫酸氧褪黑素（aMT6s）反应。卵巢切除导致ISO诱导的尿aMT6s排泄增加，而睾丸切除则导致减少。在从去势、性激素处理的去势和假手术大鼠获得的松果体和血清样本中检测了褪黑素对ISO的反应。一致地，卵巢切除增加了松果体和血清对ISO的褪黑素反应，而睾丸切除则降低了反应；雌二醇和睾酮处理分别逆转了这些作用。在去势、性激素处理的去势和假手术大鼠的单个松果体中测量了3H-二氢阿普洛尔结合。卵巢切除增加了β-肾上腺素能受体的密度，而睾丸切除则降低了密度；雌二醇和睾酮替代分别阻断了这些作用。未发现对受体解离常数（Kd）值有显著影响。这些数据表明性激素通过改变β-肾上腺素能机制来调节松果体褪黑素的产生。
