Age-related changes of norepinephrine content in kidneys of spontaneously hypertensive and Wistar-Kyoto rats.
Renal norepinephrine (NE) content was determined during the development of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) rats in an attempt to correlate biochemical changes with the reported functional changes occurring in hypertension development in the SHR. In contrast to WKY rats, in which the levels of NE remained relatively constant with age, renal NE content in the SHR was highest at the 4th week of age, decreasing transiently during the 5th, 6th, and 7th weeks, and then again reaching a plateau during the 8th week. The fall in NE content in the kidney is associated with a rise in blood pressure with age in SHR and suggests a relationship between NE levels and hypertension.