Renal renin-angiotensin system activity in naturally reared and cross-fostered spontaneously hypertensive rats

• Published in: American journal of hypertension Vol. 16; no. 10; pp. 864 - 869
• Main Authors: Gouldsborough, Ingrid, Lindop, George B.M, Ashton, Nick
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.10.2003; Oxford University Press; Elsevier Science
• Subjects: Angiotensin II - blood; Angiotensin II - pharmacology; Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; cross-fostering; Cyclic AMP - metabolism; Experimental diseases; Female; Gene Expression; Hypertension, Renal - metabolism; In Situ Hybridization; Kidney; Kidney Tubules, Proximal - drug effects; Kidney Tubules, Proximal - metabolism; Medical sciences; Pregnancy; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Angiotensin, Type 1 - genetics; Renin - genetics; renin-angiotensin system; Renin-Angiotensin System - physiology; Second Messenger Systems - physiology; Social Environment; Species Specificity; spontaneously hypertensive rat; Vasoconstrictor Agents - blood; Vasoconstrictor Agents - pharmacology; spontaneously hypertensive rat; cross-fostering; Kidney; renin-angiotensin system; Hypertension; Rat; Pathogenesis; Rodentia; Cardiovascular disease; Hereditary; Vertebrata; Renin angiotensin system; Mammalia; Animal
• ISSN: 0895-7061; 1879-1905; 1941-7225
• DOI: 10.1016/S0895-7061(03)00999-3

Young (4 week) spontaneously hypertensive rats (SHR) exhibit greater renal responses to angiotensin II (Ang II) than normotensive Wistar Kyoto (WKY) rats. SHR pups cross-fostering to a WKY dam at birth (SHRX) are less sensitive to Ang II and have lower adult blood pressure. The aim of this study was to compare renal renin-angiotensin system activity in young naturally reared and cross-fostered SHR pups. SHR and WKY rats were reared either by their natural mothers or by a foster mother of the opposite strain. At 5, 10, and 15 days of age, renal tissue renin activity and Ang II concentration were measured by radioimmunoassay. Renin-secreting cells were identified by in situ hybridization and AT1 receptor expression was compared using Western blots. Ang II-mediated cAMP generation was measured in isolated proximal tubules. Tissue renin activity and numbers of renin-secreting cells did not differ, but Ang II was higher in SHRX. The AT1 receptor expression was significantly lower in SHRX compared with SHR. Basal and Ang II-stimulated cAMP was lower in SHR tubules compared with WKY and SHRX tubules. Cross-fostering reversed the increased renal sensitivity of the SHR to Ang II. These data suggest that renal AT1 receptor expression can be manipulated during the postnatal period and that this may affect adult blood pressure.