Heisler S, Veilleux R, Labrie F
Mol Cell Endocrinol. 1984 May;35(2-3):183-8. doi: 10.1016/0303-7207(84)90015-7.
The identification of PHI (the 27-amino acid peptide (P) having an N-terminal histidine (H) and a C-terminal isoleucine amide (I] in median eminence suggested that PHI influences the secretory function of the anterior pituitary. The effects of PHI on ACTH release from clonal mouse pituitary corticotrophs were investigated. The secretory response to PHI was correlated with a prior increase in cyclic AMP accumulation. Both cyclic AMP synthesis and ACTH secretion were increased by PHI in a concentration-dependent manner. PHI was a less effective agonist of cyclic nucleotide synthesis and ACTH secretion than VIP. The secretory response to PHI was blocked by the calcium channel antagonist, nifedipine, and by dexamethasone. Somatostatin and oxotremorine blocked both PHI-stimulated cyclic AMP formation and ACTH secretion. The observation that VIP in high concentrations can elicit ACTH secretion from normal rat anterior pituitary suggested that a VIP-like substance may modulate ACTH secretion. However, the finding that PHI does not elicit ACTH release from primary cultures of dispersed anterior pituitary, coupled to its relatively lower potency compared to VIP, indicate that corticotrophs are not an important target for PHI.
在正中隆起中鉴定出PHI（一种27个氨基酸的肽，N端为组氨酸（H），C端为异亮氨酸酰胺（I））表明PHI影响垂体前叶的分泌功能。研究了PHI对克隆的小鼠垂体促肾上腺皮质激素细胞释放促肾上腺皮质激素（ACTH）的影响。对PHI的分泌反应与环磷酸腺苷（cAMP）积累的先前增加相关。PHI以浓度依赖的方式增加cAMP合成和ACTH分泌。与血管活性肠肽（VIP）相比，PHI是一种对环核苷酸合成和ACTH分泌效果较差的激动剂。对PHI的分泌反应被钙通道拮抗剂硝苯地平和地塞米松阻断。生长抑素和氧化震颤素阻断了PHI刺激的cAMP形成和ACTH分泌。高浓度的VIP可从正常大鼠垂体前叶引发ACTH分泌，这一观察结果表明一种类似VIP的物质可能调节ACTH分泌。然而，PHI不能从分散的垂体前叶原代培养物中引发ACTH释放，以及与VIP相比其效力相对较低的发现，表明促肾上腺皮质激素细胞不是PHI的重要靶标。
