De Souza E B
Neuroendocrinology. 1985 Oct;41(4):289-96. doi: 10.1159/000124192.
In the present study, we have used 125I-cyanopindolol (125ICYP) to identify, characterize, and localize beta-adrenergic receptors in bovine, rat, and human pituitary gland by in vitro labeling light microscopic autoradiography. The binding of 125ICYP to slide-mounted bovine pituitary sections was saturable and of high affinity with an apparent Kd of 0.2 nM. The pharmacological profile of 125ICYP binding obtained from competition studies demonstrates that the beta-adrenergic receptors in the pituitary gland are predominantly of the beta 2 subtype. Rat pituitary autoradiograms show specific binding sites for 125ICYP in anterior, intermediate, and posterior lobes with highest concentrations found in the intermediate lobe and progressively lower concentrations in posterior and anterior lobes, respectively. Autoradiograms of 125ICYP binding in human pituitary show a significantly higher concentration of beta 2-adrenergic receptors in posterior than in anterior lobe of the pituitary. There is a homogeneous distribution of beta 2-adrenergic receptors within each lobe of both rat and human pituitary glands. The results of the present study provide the first visualization of beta 2-adrenergic receptors in rat and human pituitary and demonstrate the presence of significant concentrations of beta 2-adrenergic receptors in the posterior lobe. The data support a role for epinephrine and norepinephrine in modulating pituitary function.
在本研究中，我们使用了125I-氰基吲哚洛尔（125ICYP），通过体外标记光镜放射自显影技术，对牛、大鼠和人类垂体中的β-肾上腺素能受体进行鉴定、表征和定位。125ICYP与载玻片上的牛垂体切片的结合是可饱和的，且具有高亲和力，其表观解离常数（Kd）为0.2 nM。竞争研究获得的125ICYP结合的药理学特征表明，垂体中的β-肾上腺素能受体主要为β2亚型。大鼠垂体放射自显影片显示，125ICYP在前叶、中间叶和后叶均有特异性结合位点，其中中间叶浓度最高，后叶和前叶浓度逐渐降低。125ICYP与人垂体结合的放射自显影片显示，垂体后叶中β2-肾上腺素能受体的浓度明显高于前叶。大鼠和人类垂体的每个叶内β2-肾上腺素能受体均呈均匀分布。本研究结果首次显示了大鼠和人类垂体中β2-肾上腺素能受体的情况，并证明后叶中存在高浓度的β2-肾上腺素能受体。这些数据支持肾上腺素和去甲肾上腺素在调节垂体功能中发挥作用。
