Enz A, Iwangoff P, Chappuis A
Gerontology. 1978;24 Suppl 1:115-25. doi: 10.1159/000212305.
Dihydroergotoxine mesylate (DHET; active substance of Hydergine) was shown to be a stronger inhibitor of the low-Km than of the high-Km phosphodiestrase (PE) in cat and rat brain homogenates. The inhibition due to DHET was greater when a purified low-Km PE preparation originating from a sonicated pellet (100,000 g) of rat brain tissue was used. The drug alters the kinetic properties of the enzyme, producing a lowering of the negative cooperativity effect. This kind of PE inhibition is of particular importance at normal cellular cAMP levels, but does not interfere with cAMP production by hormonal stimulation.
甲磺酸双氢麦角毒碱（DHET；喜得镇的活性物质）在猫和大鼠脑匀浆中对低Km磷酸二酯酶（PE）的抑制作用比对高Km磷酸二酯酶更强。当使用源自大鼠脑组织超声破碎沉淀（100,000 g）的纯化低Km PE制剂时，DHET引起的抑制作用更大。该药物改变了酶的动力学性质，降低了负协同效应。这种PE抑制在正常细胞cAMP水平时尤为重要，但不干扰激素刺激引起的cAMP生成。
