Zoukhri D, Sergheraert C, Rossignol B
Laboratoire de Biochimie des Transports Cellulaires, Centre National de la Recherche Scientifique URA 1116, Université Paris-Sud, Orsay, France.
Am J Physiol. 1993 Apr;264(4 Pt 1):C1045-50. doi: 10.1152/ajpcell.1993.264.4.C1045.
In this work we show that, although both phorbol 12-myristate 13-acetate (PMA) and 4 beta-phorbol 12,13-dibutyrate (PdBu) stimulate the protein discharge in the rat lacrimal gland with the same half-maximal effective concentration (EC50 approximately 2 x 10(-7) M), PdBu is more efficient in eliciting this response compared with PMA. We also show that sphingosine and chelerythrine have no inhibitory effect on the protein discharge stimulated by PMA or PdBu at concentrations up to 2 x 10(-4) and 3 x 10(-5) M, respectively. With staurosporine, a complete inhibition could not be obtained even at 1 microM. However, only with trifluoperazine (TFP) we obtained a complete inhibition of the PMA-induced protein discharge at 10(-4) M TFP. On the other hand, we show that three diacylglycerol-permeant analogues (1-oleoyl-2-acetyl-sn-glycerol, 1,2-dioctanoyl-sn-glycerol, and 1,2-didecanoyl-sn-glycerol) do not stimulate protein discharge. In a previous report from our laboratory (30), we showed that the rat lacrimal gland expresses the alpha-isoform of protein kinase C (PKC). In this study, using specific antibodies directed against the newly identified isoforms of PKC, we show on a diethylaminoethyl-cellulose fraction that, besides PKC-alpha, the rat lacrimal gland expresses PKC-epsilon, as previously suggested by Dartt et al. (11), and PKC-delta. Our results question the direct implication of PKC activity as a sole effector of the phorbol ester-stimulated protein secretion in the rat lacrimal gland.
在本研究中，我们发现，虽然佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）和4β - 佛波醇12,13 - 二丁酸酯（PdBu）以相同的半数最大有效浓度（EC50约为2×10⁻⁷ M）刺激大鼠泪腺中的蛋白质分泌，但与PMA相比，PdBu引发该反应的效率更高。我们还发现，鞘氨醇和白屈菜红碱分别在浓度高达2×10⁻⁴ M和3×10⁻⁵ M时，对PMA或PdBu刺激的蛋白质分泌没有抑制作用。对于星形孢菌素，即使在1 μM时也无法实现完全抑制。然而，仅在三氟拉嗪（TFP）浓度为10⁻⁴ M时，我们才实现了对PMA诱导的蛋白质分泌的完全抑制。另一方面，我们发现三种二酰基甘油渗透类似物（1 - 油酰基 - 2 - 乙酰基 - sn - 甘油、1,2 - 二辛酰基 - sn - 甘油和1,2 - 二癸酰基 - sn - 甘油）不会刺激蛋白质分泌。在我们实验室之前的一份报告（30）中，我们表明大鼠泪腺表达蛋白激酶C（PKC）的α亚型。在本研究中，使用针对新鉴定的PKC亚型的特异性抗体，我们在二乙氨基乙基纤维素级分上表明，除了PKC - α外，大鼠泪腺如Dartt等人（11）之前所暗示的那样表达PKC - ε，以及PKC - δ。我们的结果对PKC活性作为大鼠泪腺中佛波酯刺激的蛋白质分泌的唯一效应器的直接作用提出了质疑。
