Fig. 7.

Expression of adrenergic signaling by sex and age in response to 1 week of isoproterenol (ISO). a β₁-adrenergic receptor (ADRB1) expression was upregulated in adult males. b β₂-adrenergic receptor (ADRB2) expression was upregulated in adult and aged males. c Adenylyl cyclase 9 (ADCY9) expression was upregulated in males of all three ages and downregulated in aged females. d Calcium voltage-gated channel α1 (CACNA1) expression was upregulated in juvenile males and adults of both sexes. e Ryanodine receptor 1 (RYR1) expression was downregulated in adult females and aged females, while unchanged in juveniles. Gene expression was assessed by qRT-PCR and expressed as fold change relative to CON within age and sex. Data are presented as means ± SEM. *P < 0.05 as assessed Student’s t-test to compare ISO and CON within age and sex, n = 6/group.