A novel natriuretic, hypotensive factor derived from the spleen

Area of Science:

• Physiology
• Endocrinology
• Nephrology

Background:

• Splenectomy abolishes the plasma volume reduction caused by atrial natriuretic factor.
• The spleen may contain endogenous factors influencing cardiorenal homeostasis.

Purpose of the Study:

• To determine if the spleen contains a factor that influences cardiorenal homeostasis.
• To characterize the physiological effects of spleen extract in rats.

Main Methods:

• Rat spleens were homogenized and extracted using ultrafiltration and C18 affinity chromatography.
• The spleen extract was administered intravenously to conscious rats.
• Urine output, electrolyte excretion, water clearance, and blood pressure were monitored.

Main Results:

• Spleen extract induced a dose-dependent diuresis, natriuresis, kaliuresis, and chloruresis.
• A significant decrease in blood pressure was observed post-injection without a compensatory heart rate increase.
• Solute-free water clearance was inversely related to urine output.

Conclusions:

• The mammalian spleen contains a natriuretic and hypotensive factor.
• This spleen-derived factor may play a role in regulating cardiorenal homeostasis.