Ki: 19 nM (oxytocin receptor), 3.7 nM (vasopressin V1a receptor)

Systemic administration of nonpenetrant oxytocin receptor antagonist L-371,257 (0.5 and 1.0 mg/kg; i.p. injection) stimulates weight gain in rats. Animal Model: Six-hour fasted rats Dosage: 0.5 and 1.0 mg/kg Administration: Intraperitoneal injection (a single) 30-45 minutes prior to the start of the dark cycle and access to food; Intraperitoneal injection (given repeatedly) over 6 days. Result: A single injection significantly stimulated weight gain at 0.5 and 1.0 mg/kg relative to vehicle treatment. When given repeatedly over 6 days, 0.5 mg/kg significantly stimulated body weight gain (10.5±2.2 g) relative to vehicle treatment (4.7±2.7 g).

L-371,257 是一种口服生物有效的，不能透过血脑屏障的，竞争性的，选择性催产素受体 (oxytocin receptor) 拮抗剂 (pA2=8.4)，对催产素受体 (Ki=19 nM) 和血管加压素 V1a 受体 (vasopressin V1a receptor，Ki=3.7 nM) 具有高亲和力。