Melmed S, Carlson H E, Hershman J M
Clin Endocrinol (Oxf). 1982 Jan;16(1):97-100. doi: 10.1111/j.1365-2265.1982.tb03152.x.
Because histidyl-proline diketopiperazine (HPD), a metabolite of TRH, has been shown to suppress prolactin (PRL) release by rat pituitary tumour cells, human pituitary tumour cells were exposed to this compound. Monolayer cell cultures were initiated from pituitary tissue removed by transsphenoidal surgery from two patients with prolactin-secreting microadenomas. Tumour fragments were mechanically dispersed; cells were seeded into multiwell plates and incubated in Ham's F-10 medium enriched with fetal calf serum (20%). HPD (7.5 ng/ml) suppressed PRL release by both tumour cell cultures. Theophylline reversed the inhibition of PRL release induced by HPD. The data raise the possibility that HPD may act as an endogenous prolactin-inhibiting factor in man.
由于促甲状腺激素释放激素（TRH）的代谢产物组氨酰-脯氨酸二酮哌嗪（HPD）已被证明可抑制大鼠垂体肿瘤细胞释放催乳素（PRL），因此将人垂体肿瘤细胞暴露于该化合物中。从两名分泌催乳素的微腺瘤患者经蝶窦手术切除的垂体组织中开始进行单层细胞培养。将肿瘤碎片机械分散；将细胞接种到多孔板中，并在富含胎牛血清（20%）的Ham's F-10培养基中培养。HPD（7.5 ng/ml）抑制了两种肿瘤细胞培养物中PRL的释放。茶碱逆转了HPD对PRL释放的抑制作用。这些数据增加了HPD可能作为人体内源性催乳素抑制因子的可能性。
