Microlocalization and effects of adrenomedullin in nephron segments and in mesangial cells of the rat

作者：Owada A; Nonoguchi H; Terada Y; Marumo F; Tomita K

来源：American Journal of Physiology - Renal Fluid and Electrolyte Physiology, 1997, 272(6): F691-F697.

• microperfusion
• glomerulus
• collecting ducts
• reverse transcription-polymerase chain reaction
• Northern blot analysis
• microdissected nephron segments
• cultured mesangial cells

We examined microlocalization of mRNA coding for adrenomedullin (AM), using reverse transcription-polymerase chain reaction (RT-PCR), and the effects of AM on adenosine 3',5'-cyclic monophosphate (cAMP) generation and water transport in microdissected rat nephron segments. We also examined intraglomerular site of the expression of AM and AM-stimulated cAMP generation in cultured rat mesangial cells (MC). RT-PCR demonstrated the signals for AM mRNA in glomerulus (Glm), cortical collecting duct (CCD), outer medullary collecting duct (OMCD), and inner medullary collecting duct (IMCD) but not in proximal convoluted tubule (PCT) or medullary thick ascending limb (MTAL). AM (10(-7) M) stimulated cAMP generation in Glm much greater than CCD = IMCD > OMCD but not in PCT or MTAL, which corresponded to the results of the expression of AM mRNA. AM (10(-8) M) slightly increased osmotic water permeability by 24% in perfused terminal IMCD. Northern blot analysis revealed high expression of AM mRNA in MC. AM (10(-7) M) stimulated cAMP generation in MC both in the presence and absence of fetal calf serum, suggesting that AM-dependent cAMP generation was evident both in cycling MC and in quiescent MC. AM may work as a diuretic peptide mainly by increasing glomerular filtration rate via cAMP in MC.

• 出版日期1997-6