[Renin synthesis by renal cells during chronic inhibition of angiotensin I converting enzyme].

A study was performed on renin synthesis in order to evaluate changes that occur in renal cells during angiotensin-converting enzyme chronic inhibition of Ang I in mice. Immediately after weaning, 20 CF1 mice received 20 mg/l enalapril maleate in drinking water during 16 months; this group was compared with a control group. Kidney tissue was processed and studies using optical and electron microscope immunochemical techniques were performed. An antirenin antibody was used, and in situ hybridization was performed to keep track of renin mRNA with a digoxygenin-marked probe. We calculated the number of juxtaglomerular apparatus (JGA), afferent arterioles (AA) and arcuate vessels (AV) immunomarked (IM) with antirenin and antidigoxygenin. These parameters were rendered in JGA rates (%IMJGA) and AA (%IMAA) and AV (%IMAV) marked rates (%AV), and in the rate of JGA (%SJGA), AA (%SAA) and AV (%SAV) hybridization signs. Electron microscope readings were used to determine the number of gold particles per renin granule. An increase in the number of renin-producing cells was observed in animals having received enalapril chronically, beyond AJG and AA, since marking was observed in arcuate vessels. The mean %MJGA value was lower in control animals (65.6% +/- 2.4) than in treated animals (94.2% +/- 3 p < 0.05). Similar findings occurred with %MAA: 23.6% +/- 3, (control animals) vs. 41.6% +/- 2.3, p < 0.05 (treated animals). AV were not marked in the control group, as they were in treated animals where %MAV was 4.4% +/- 1.6. The mRNA distribution was different in animals with RAS inhibition as compared with control animals.(ABSTRACT TRUNCATED AT 250 WORDS)