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Renin granules isolated from rat kidney cortex by continuous colloidal silica (Percoll) density gradient
Renal Physiology
|January 1, 1986
Summary
Researchers isolated active renin granules from rat kidney cortex using Percoll density gradient centrifugation. The purified granules showed high renin activity and lacked other enzyme activities, confirming they contain only active renin.
Area of Science:
- Biochemistry
- Renal Physiology
- Cell Biology
Background:
- Renin is a key enzyme in the renin-angiotensin system, regulating blood pressure.
- Understanding renin granule composition is crucial for studying its physiological role.
- Previous studies have suggested heterogeneity in renin granule content.
Purpose of the Study:
- To isolate and characterize renin granules from rat kidney cortex.
- To determine the enzymatic content of purified renin granules.
- To ascertain whether renin granules contain only active renin.
Main Methods:
- Rat kidney cortex was homogenized and subjected to Percoll density gradient centrifugation.
- Renin activity was measured in gradient fractions.
- Activities of reference enzymes (succinate dehydrogenase, acid phosphatase, glucose-6-phosphatase) were assessed.
- Pepstatin column chromatography was used to assess renin activation state.
Main Results:
- A major peak of renin activity was isolated at a density of 1.12-1.13 g/ml.
- Specific renin activity in the peak fraction was enriched approximately 70-fold compared to the homogenate.
- Activities of other tested enzymes were undetectable in the peak fraction.
- No trypsin-activated renin was detected in breakthrough fractions from a pepstatin column.
Conclusions:
- Renin granules isolated from rat kidney cortex by Percoll density gradient centrifugation are highly purified.
- The purified renin granules contain exclusively active renin.
- This finding supports the homogeneity of renin content within these granules.