Lettieri J, Fung H L
Res Commun Chem Pathol Pharmacol. 1978 Oct;22(1):107-18.
Although gamma-butyrolactone (GBL) rapidly converts to gamma-hydroxybutyrate (GHB) in vivo, the lactone gave significantly more prolonged hypnotic effects than GHB when equimolar doses were compared both parenterally and orally in rats. Plasma drug concentrations were higher after GBL administration through both routes, consistent with the observed differences in the pharmacological activity of these two compounds. Oral GBL was absorbed much faster than oral GHB, with the dual effects of decreasing potential first-pass metabolism and elevating plasma drug concentrations to the region where capacity-limited elimination is operative. Parenteral GBL produced a slower initial drug plasma clearance than parenteral GHB. In spite of the rapid metabolism of GBL to GHB, the apparent tissue distribution of these two compounds may be different.
尽管γ-丁内酯（GBL）在体内会迅速转化为γ-羟基丁酸（GHB），但在大鼠体内通过肠胃外和口服途径比较等摩尔剂量时，内酯产生的催眠作用比GHB持续时间长得多。通过两种途径给予GBL后，血浆药物浓度更高，这与这两种化合物药理活性的观察差异一致。口服GBL的吸收速度比口服GHB快得多，具有降低潜在首过代谢和将血浆药物浓度提高到容量限制消除起作用区域的双重效果。肠胃外给予GBL时，药物血浆初始清除速度比肠胃外给予GHB慢。尽管GBL迅速代谢为GHB，但这两种化合物的表观组织分布可能不同。
