Bonilla-Felix M, Jiang W
Department of Pediatrics, University of Texas-Health Science Center at Houston 77030, USA.
Am J Physiol. 1996 Jul;271(1 Pt 2):F30-6. doi: 10.1152/ajprenal.1996.271.1.F30.
Arginine vasopressin (AVP)-stimulated cAMP generation is decreased in the immature collecting duct (CD). This is the result of prostaglandin antagonism, most likely via the inhibitory guanine nucleotide-binding protein (Gi). The EP3-subtype prostaglandin E2 (PGE2) receptor, which is coupled to Gi, could mediate this effect. We studied the developmental expression of EP3 receptor in the rabbit kidney. Higher levels of EP3 mRNA were observed in the immature kidney using three different assays: 1) reverse transcription-polymerase chain reaction (RT-PCR) with internal standard, 2) competitive PCR, and 3) ribonuclease protection assay. The highest levels were observed at 2 wk of age. RT-PCR from isolated nephron segments detected EP3 mRNA in the medullary thick ascending limb, cortical CD (CCD), and inner medullary CD (IMCD) of adult and immature kidneys. We conclude that 1) renal expression of EP3 mRNA is increased in immature kidneys and 2) EP3 mRNA is localized in the distal nephron. This suggests that EP3 receptor may play a role in the regulation of distal tubular transport during development.
精氨酸加压素（AVP）刺激的环磷酸腺苷（cAMP）生成在未成熟的集合管（CD）中减少。这是前列腺素拮抗作用的结果，最有可能是通过抑制性鸟嘌呤核苷酸结合蛋白（Gi）介导的。与Gi偶联的前列腺素E2（PGE2）受体的EP3亚型可能介导了这种作用。我们研究了兔肾中EP3受体的发育表达情况。使用三种不同的检测方法在未成熟肾脏中观察到了较高水平的EP3 mRNA：1）带有内标的逆转录聚合酶链反应（RT-PCR）；2）竞争性PCR；3）核糖核酸酶保护分析。在2周龄时观察到最高水平。从分离的肾单位节段进行的RT-PCR检测到成年和未成熟肾脏的髓质厚升支、皮质集合管（CCD）和内髓集合管（IMCD）中有EP3 mRNA。我们得出结论：1）未成熟肾脏中EP3 mRNA的肾表达增加；2）EP3 mRNA定位于远端肾单位。这表明EP3受体可能在发育过程中远端肾小管转运的调节中发挥作用。
