Anderson R J, Breckon R, Colston D
Denver Veterans Affairs Medical Center, CO.
Biochem J. 1991 Oct 1;279 ( Pt 1)(Pt 1):23-7. doi: 10.1042/bj2790023.
Forskolin, a naturally occurring activator of adenylate cyclase, inhibits total and high-affinity cyclic AMP phosphodiesterase activity in soluble and particulate fractions of cultured LLC-PK1 renal epithelial cells. The naturally occurring forskolin analogue 1,9-dideoxyforskolin, which does not stimulate adenylate cyclase activity, is a more potent inhibitor of cyclic AMP phosphodiesterase activity than forskolin. To clarify the structural feature of the forskolin molecule responsible for inhibition of cyclic AMP phosphodiesterase activity, the effects of two agents which share structural identity with portions of the forskolin ring were tested. The steroid 5-pregnenolone, but not the hexose alpha-D-galactose, inhibited cyclic AMP phosphodiesterase activity in LLC-PK1 cells. Forskolin and 1,9-dideoxyforskolin both stimulate protein kinase C activity in LLC-PK1 cells. The effect of 1,9-dideoxyforskolin in stimulating LLC-PK1 protein kinase C activity can be attenuated by staurosporine. Both 5-pregnenolone and alpha-D-galactose also stimulate protein kinase C activity in LLC-PK1 cells. 5-Pregnenolone and the phorbol ester phorbol 12-myristate 13-acetate cause translocation of protein kinase C from a soluble to a particulate fraction, while both 1,9-dideoxyforskolin and alpha-D-galactose increase protein kinase C activity in both soluble and particulate fractions. Our results demonstrate that forskolin exerts diverse enzymic effects in cultured LLC-PK1 cells.
福司可林是一种天然存在的腺苷酸环化酶激活剂，可抑制培养的LLC-PK1肾上皮细胞可溶性和颗粒部分中的总环磷酸腺苷（cAMP）和高亲和力cAMP磷酸二酯酶活性。天然存在的福司可林类似物1,9-二脱氧福司可林不刺激腺苷酸环化酶活性，却是比福司可林更有效的cAMP磷酸二酯酶活性抑制剂。为阐明福司可林分子中负责抑制cAMP磷酸二酯酶活性的结构特征，测试了两种与福司可林环部分具有结构一致性的试剂的作用。甾体5-孕烯醇酮可抑制LLC-PK1细胞中的cAMP磷酸二酯酶活性，而己糖α-D-半乳糖则无此作用。福司可林和1,9-二脱氧福司可林均可刺激LLC-PK1细胞中的蛋白激酶C活性。1,9-二脱氧福司可林刺激LLC-PK1蛋白激酶C活性的作用可被星形孢菌素减弱。5-孕烯醇酮和α-D-半乳糖也可刺激LLC-PK1细胞中的蛋白激酶C活性。5-孕烯醇酮和佛波酯佛波醇12-肉豆蔻酸酯13-乙酸酯可使蛋白激酶C从可溶性部分转位至颗粒部分，而1,�-二脱氧福司可林和α-D-半乳糖则可增加可溶性和颗粒部分中的蛋白激酶C活性。我们的结果表明，福司可林在培养的LLC-PK1细胞中发挥多种酶促作用。
