Cortisol feedback regulation of pulsatile ACTH secretion in fetal sheep during late gestation.
Cortisol feedback regulation of pulsatile ACTH secretion in fetal sheep during late gestation.
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皮质醇对妊娠晚期胎羊脉动 ACTH 分泌的反馈调节。
DOI：
10.1152/ajpendo.1994.267.4.e521
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Yellon,SM
中科院分区：
文献类型：
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作者：
Apostolakis,EM;Longo,LD;Yellon,SM
在胎羊中，血浆皮质醇和促肾上腺皮质激素（ACTH）浓度在妊娠后期增加，并在出生后72小时（约妊娠146天）内激增。为了确定皮质醇在控制搏动ACTH分泌中的反馈作用，在妊娠133天，6例长期导管插管的胎儿接受皮质醇（1微克/小时静脉注射）治疗96小时。皮质醇治疗前（133天）、期间（134天和137天）和后（142天）（5分钟取样2小时），每个胎儿都有明显的促肾上腺皮质激素脉冲。在134天，ACTH脉冲峰值、最低点和估计分泌率显著增加，而频率、振幅、平均浓度和皮质醇结合能力（CBC）不变。在第137天，与前处理对照组相比，搏动ACTH分泌的大多数特征仍然增强。在142天（注射后96小时），ACTH分泌参数恢复到预处理水平，但皮质醇浓度仍然升高。142天时再次注射皮质醇，22-24小时后，ACTH分泌除振幅、分泌速率和CBC活性外，其他参数均有所增加。数据表明缺乏皮质醇负反馈调节搏动ACTH分泌。相反，伴随皮质醇输注的ACTH升高表明，皮质醇对羊胎儿近月龄ACTH分泌有正前馈影响。
In fetal sheep, plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations increase during late gestation to surge within 72 h of birth (approximately 146 days gestation). To determine the feedback role of cortisol in control of pulsatile ACTH secretion, six chronically catheterized fetuses were treated with cortisol (1 microgram/h i.v.) for 96 h at 133 days gestation. Before (133 days), during (134 and 137 days), and after (142 days) cortisol treatment (5-min sampling for 2 h), ACTH pulses were evident in each fetus. At 134 days, ACTH pulse peak, nadir, and estimated secretory rate were significantly increased while frequency, amplitude, mean concentrations, and cortisol binding capacity (CBC) were unchanged. At 137 days, most characteristics of pulsatile ACTH secretion remained enhanced compared with pretreatment controls. At 142 days (96 h postinfusion), ACTH secretion parameters returned to pretreatment levels, but cortisol concentrations remained elevated. Cortisol infusion was then reinitiated at 142 days and, 22–24 h later, parameters of ACTH secretion increased except for amplitude, secretory rate, and CBC activity. The data indicate an absence of cortisol negative feedback regulation of pulsatile ACTH secretion. Rather, the ACTH rise that accompanied cortisol infusion suggests that cortisol exerts a positive feedforward influence on ACTH secretion in the ovine fetus near term.