Renin-angiotensin system in genetically hypertensive mice

Area of Science:

• Physiology
• Genetics
• Biochemistry

Background:

• The renin-angiotensin system (RAS) plays a crucial role in blood pressure regulation.
• Genetic models of hypertension offer insights into RAS involvement in blood pressure control.

Purpose of the Study:

• To investigate the role of the renin-angiotensin system in genetically distinct mouse models with varying blood pressures (hypertensive, normotensive, and low blood pressure).
• To compare renin levels and activity in plasma, kidney, and submaxillary gland across these mouse lines.

Main Methods:

• Enzymatic assay and direct radioimmunoassay (DRIA) were used to determine renin levels.
• Plasma samples were subjected to trypsinization to differentiate between active and inactive renin.
• Renin content and activity were measured in plasma, kidney, and submaxillary gland tissues.

Main Results:

• No significant differences in plasma renin activity (PRA) or plasma renin content were observed among the different mouse lines, sexes, or generations.
• Inactive renin was detected in mouse plasma, similar to other species, with active renin comprising 54-77% of the total.
• Renal renin content showed no significant variation across the groups.
• Submaxillary gland renin content and activity were notably higher in male mice across all genetic lines.

Conclusions:

• The findings suggest that the renin-angiotensin system may not be a primary contributor to the established phase of hypertension in these genetic mouse models.
• The elevated submaxillary gland renin in males warrants further investigation regarding its specific role, if any, in blood pressure regulation.