Sueldo C E, Duda M, Kletzky O A
Am J Obstet Gynecol. 1986 Feb;154(2):424-7. doi: 10.1016/0002-9378(86)90683-6.
It is known that the administration of serotonin or its precursors induces the release of prolactin. This study was performed (1) to determine the minimal dose of 5-hydroxytryptophan that would produce a consistent and significant prolactin increase and (2) to establish the frequency of 5-hydroxytryptophan administration necessary to induce a persistent prolactin increase. Nine normal male subjects participated in 27 independent studies following pretreatment with 100 mg of carbidopa given every 8 hours for 2 days. Doses of 0.2, 0.4, and 0.8 mg/kg/hr of 5-hydroxytryptophan were initially infused for 30 minutes, and serum prolactin was measured every 15 minutes for 2 1/2 hours. The urinary 5-hydroxyindoleacetic acid/creatinine ratio was determined in aliquots collected during 3 hours before, during, and after the intravenous infusion. 5-Hydroxytryptophan at a dosage of 0.4 mg/kg/hr was the minimal amount to elicit a consistent and significant prolactin increase (p less than 0.01). A positive correlation (r = 0.907, p less than 0.002) was also demonstrated between the maximal prolactin response and the 5-hydroxyindoleacetic acid/creatinine ratio. Thus 0.4 mg/kg/hr of 5-hydroxytryptophan was administered sequentially three times at intervals of 2, 4, 6, 8, and 12 hours. With exception of the 12-hour interval a significantly smaller plasma prolactin increase was seen following the third dose of 5-hydroxytryptophan (p less than 0.05). Furthermore, the nadir for this diminished prolactin response occurred at 4 hours (p less than 0.01). This phenomenon may represent a down regulation of the serotonin receptors induced by the repetitive administration of 5-hydroxytryptophan. In conclusion, this study has demonstrated a dose-related prolactin response to increasing doses of 5-hydroxytryptophan. The maximum down regulation of prolactin release occurred when 5-hydroxytryptophan was administered at 4-hour intervals.
已知给予血清素或其前体可诱导催乳素释放。本研究旨在：（1）确定能使催乳素持续且显著升高的5-羟色氨酸最小剂量；（2）确定诱导催乳素持续升高所需的5-羟色氨酸给药频率。9名正常男性受试者在接受每8小时100mg卡比多巴预处理2天后，参与了27项独立研究。最初以0.2、0.4和0.8mg/kg/hr的剂量输注5-羟色氨酸30分钟，每15分钟测量血清催乳素，共2.5小时。在静脉输注前、输注期间和输注后的3小时内收集的等分试样中测定尿5-羟吲哚乙酸/肌酐比值。0.4mg/kg/hr的5-羟色氨酸剂量是引起催乳素持续且显著升高的最小量（p<0.01）。最大催乳素反应与5-羟吲哚乙酸/肌酐比值之间也显示出正相关（r = 0.907，p<0.002）。因此，以0.4mg/kg/hr的剂量依次每2、4、6、8和12小时给予5-羟色氨酸三次。除了12小时间隔外，第三次给予5-羟色氨酸后血浆催乳素升高明显较小（p<0.05）。此外，这种催乳素反应减弱的最低点出现在4小时（p<0.01）。这种现象可能代表了重复给予5-羟色氨酸诱导的血清素受体下调。总之，本研究表明催乳素反应与5-羟色氨酸剂量相关。当每4小时给予5-羟色氨酸时，催乳素释放的下调最大。
