Zakar T, Olson D M
Department of Paediatrics, University of Western Ontario, Lawson Research Institute, London, Canada.
Biol Reprod. 1992 May;46(5):905-11. doi: 10.1095/biolreprod46.5.905.
The role of protein kinase C (PKC) in the control of prostaglandin production by the human amnion was studied. Amnion membranes delivered spontaneously at term were minced and treated with phorbol esters, protein kinase inhibitors, cycloheximide, and actinomycin D; prostaglandin E2 (PGE2) output then was determined. Untreated tissue produced 3.97 +/- 1.13 ng PGE2/micrograms DNA/14 h (mean +/- SEM, n = 19). Phorbol dibutyrate and 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulated PGE2 output up to 20-fold in a concentration-dependent manner with potencies corresponding to their efficacy as PKC activators. Four-beta-phorbol and 4-methoxy-TPA, which do not stimulate PKC, did not affect PGE2 output. Stimulation by TPA was blocked by staurosporine (IC50 = 57 nM) and H7; however, these PKC inhibitors did not decrease basal prostaglandin production. Cycloheximide inhibited basal and TPA-promoted PGE2 production and amino acid incorporation. Actinomycin D abolished TPA stimulation without decreasing unstimulated prostaglandin synthesis. These results show that amnion PGE2 production after labor is not maintained by PKC action, but PKC activation in this tissue causes a protein synthesis-dependent and RNA synthesis-dependent increase of PGE2 output. However, basal PGE2 production is dependent upon protein synthesis which, presumably, utilizes pre-existing mRNAs.
研究了蛋白激酶C（PKC）在人羊膜控制前列腺素产生中的作用。将足月自然分娩的羊膜切碎，并用佛波酯、蛋白激酶抑制剂、放线菌酮和放线菌素D处理；然后测定前列腺素E2（PGE2）的产量。未经处理的组织产生3.97±1.13 ng PGE2/μg DNA/14 h（平均值±标准误，n = 19）。佛波二丁酸酯和12-O-十四酰佛波醇-13-乙酸酯（TPA）以浓度依赖的方式刺激PGE2产量增加达20倍，其效力与其作为PKC激活剂的功效相对应。不刺激PKC的4-β-佛波醇和4-甲氧基-TPA不影响PGE2产量。TPA的刺激被星形孢菌素（IC50 = 57 nM）和H7阻断；然而，这些PKC抑制剂并未降低基础前列腺素的产生。放线菌酮抑制基础和TPA促进的PGE2产生以及氨基酸掺入。放线菌素D消除了TPA刺激，但未降低未刺激的前列腺素合成。这些结果表明，分娩后羊膜PGE2的产生不是由PKC作用维持的，但该组织中PKC的激活导致PGE2产量的蛋白质合成依赖性和RNA合成依赖性增加。然而，基础PGE2的产生依赖于蛋白质合成，推测其利用了预先存在的mRNA。
