Figure 2.

Cardiac-specific expression of the αMHC-AT₁ transgene. (A) Detection of the expression of the αMHC-AT₁ transgene by reverse transcriptase–PCR in 3-day-old transgenic offspring of line M2/5. Messenger RNA for the endogenous AT_1a receptor gene could be detected in heart, lung, and liver, whereas mRNA for the αMHC-AT₁ transgene could only be detected in the heart. (B) AT₁ receptor saturation binding isotherms in heart membranes derived from transgenic lines M2/5 (Left) and M4/7 (Right). Hearts were obtained from transgenic mice and wild-type littermates at day 3 (line M2/5) or days 5–7 (line M4/7) after birth. Data shown represent means ± SEM for duplicate determinations of three hearts in each group. Transgenic offspring express significantly more AT₁ receptors in the heart than their nontransgenic littermates.