Siever L J, Tamminga C, Pert A
Psychopharmacology (Berl). 1987;91(3):342-4. doi: 10.1007/BF00518188.
Alpha 2-adrenergic receptors mediate adrenergic stimulation of growth hormone (GH) secretion in the rat. The GH response to the alpha 2-adrenergic agonist clonidine has thus been used as an index of alpha 2-adrenergic receptor responsiveness. Pharmacologic manipulations known to upregulate alpha 2-adrenergic receptor sensitivity would then be expected to result in an enhancement of the GH response to clonidine. To test this hypothesis, rats were injected in the lateral ventricle with either 6-hydroxydopamine or sterile saline. One month following the lesion, urethane-anesthetized rats from each group were administered clonidine or saline. Venous samples for plasma GH were drawn prior to or following the clonidine or saline administration. Rats administered clonidine had greater GH responses than those administered saline within either the lesioned or nonlesioned groups. The GH response to clonidine was significantly greater in the lesioned group than in the nonlesioned group. As 6-hydroxydopamine pretreatment upregulates alpha 2-adrenergic receptors, these results support the validity of the use of the GH response to clinidine as an index of alpha 2-adrenergic receptor responsiveness.
α2-肾上腺素能受体介导大鼠肾上腺素对生长激素（GH）分泌的刺激作用。因此，生长激素对α2-肾上腺素能激动剂可乐定的反应已被用作α2-肾上腺素能受体反应性的指标。已知上调α2-肾上腺素能受体敏感性的药理学操作预期会导致生长激素对可乐定反应的增强。为了验证这一假设，给大鼠侧脑室注射6-羟基多巴胺或无菌生理盐水。损伤后一个月，对每组经乌拉坦麻醉的大鼠给予可乐定或生理盐水。在给予可乐定或生理盐水之前或之后采集血浆生长激素的静脉样本。在损伤组或未损伤组中，给予可乐定的大鼠比给予生理盐水的大鼠有更大的生长激素反应。损伤组对可乐定的生长激素反应显著大于未损伤组。由于6-羟基多巴胺预处理可上调α2-肾上腺素能受体，这些结果支持将生长激素对可乐定的反应用作α2-肾上腺素能受体反应性指标的有效性。
