Takahara J, Yunoki S, Hosogi H, Yakushiji W, Kageyama J, Ofuji T
Endocrinology. 1980 Jan;106(1):343-7. doi: 10.1210/endo-106-1-343.
gamma-Aminobutyric acid (GABA; 50 or 500 microgram/10 microliter) was injected into the right lateral ventricle of urethane- or pentobarbital-anesthetized male rats. The animals were decapitated 15 min after injection. Serum GH and hypothalamic somatostatin (SRIF) concentration were measured by specific RIAs. Intraventricular GABA caused a dose-related increase in GH and SRIF. In another study, aminooxyacetic acid (5 or 20 mg) was injected ip into urethane-anesthetized rats. Aminooxyacetic acid at 20 mg produced a significant increase in both serum GH and hypothalamic SRIF. Furthermore, 12.5 mg gamma-hydroxybutyric acid (GHB) injected ip into urethane- or pentobarbital-anesthetized rats elicited a significant increase in both serum GH and hypothalamic SRIF. Pretreatment with 20 mg L-dopa produced decreases in the GHB-induced serum GH increase and in hypothalamic SRIF in pentobarbital-anesthetized rats. These results show that GABA and GHB stimulated GH secretion, which was accompanied by increased hypothalamic SRIF. Thus, the GH release induced by GABA or GHB may be partly involved in inhibiting the release of hypothalamic SRIF. As the GHB-induced GH release was inhibited by L-dopa, the stimulatory effect of GHB on GH secretion might be mediated by inhibition of the dopaminergic mechanism.
将γ-氨基丁酸（GABA；50或500微克/10微升）注射到经乌拉坦或戊巴比妥麻醉的雄性大鼠的右侧脑室。注射后15分钟将动物断头。通过特异性放射免疫分析法测定血清生长激素（GH）和下丘脑生长抑素（SRIF）浓度。脑室内注射GABA导致GH和SRIF呈剂量相关增加。在另一项研究中，将氨氧基乙酸（5或20毫克）腹腔注射到经乌拉坦麻醉的大鼠体内。20毫克氨氧基乙酸使血清GH和下丘脑SRIF均显著增加。此外，将12.5毫克γ-羟基丁酸（GHB）腹腔注射到经乌拉坦或戊巴比妥麻醉的大鼠体内，引起血清GH和下丘脑SRIF均显著增加。用20毫克左旋多巴预处理可使戊巴比妥麻醉大鼠中GHB诱导的血清GH增加和下丘脑SRIF降低。这些结果表明，GABA和GHB刺激GH分泌，同时伴有下丘脑SRIF增加。因此，GABA或GHB诱导的GH释放可能部分参与抑制下丘脑SRIF的释放。由于GHB诱导的GH释放被左旋多巴抑制，GHB对GH分泌的刺激作用可能是通过抑制多巴胺能机制介导的。
