The Relationship Between Endothelin and Blood Pressure in Pregnant Rats

Abstract

Objective: The role of endothelin in the maintenance and regulation of hypertension in spontaneously hypertensive and Wistar Kyoto rats is controversial. In view of the meager data on pregnant rats, endothelin levels and blood pressure were examined before and during pregnancy in these two strains of rats.

Methods: Endothelin levels were determined with a ¹²⁵I ET radioimmunoassay (RIA) kit. Systolic blood pressure was measured in conscious animals by an indirect tail cuff method using an electrosphygmomanometer and pneumatic pulse transducer (Narco Biosystems, Inc., Houston, TX). The mean of 3 measurements was recorded as a representative blood pressure for each rat.

Results: The decrease in blood pressure in the spontaneously hypertensive rats (SHR) during pregnancy was very impressive, and the endothelin level also fell significantly. There was no change in endothelin level in Wistar Kyoto rats (WKY) and the fall in blood pressure was also less pronounced.

Conclusions: These data indicate a mutual relationship between blood pressure and endothelin level.

Key Words:

• Endothelin
• Hypertension
• Pregnancy
• SHR
• WKY