Distribution and concentration of beta-adrenergic receptor (betaAR) subtype transcripts (beta1AR, beta2AR, and beta3AR) were investigated in porcine and rat tissues. Reverse transcription (RT) coupled with PCR indicated the presence of beta1AR and beta2AR transcripts in porcine left ventricle, lung, longissimus muscle, and subcutaneous adipose tissue. The RT-PCR indicated that beta3AR transcripts were present in porcine subcutaneous adipose tissue, and transcripts were suggested in left ventricle and lung, but they were not detected in longissimus muscle. Quantitative ribonuclease protection assays indicated that the porcine beta1AR, beta2AR, and beta3AR transcript concentrations (amol/microg of total RNA) were, respectively as follows: heart left ventricle = 6.1, 2.4, and .02; lung = 3.8, 1.9, and .01; liver = 1.7, 2.1, and undetectable; skeletal muscle = 1.7, 1.1, .02; subcutaneous adipose tissue = 1.3, .4, .14. The proportions of porcine betaAR subtypes (beta1AR:beta2AR:beta3AR) were as follows: heart left ventricle = 72:28:.25; lung = 67:33:.2; liver = 45:55:0; skeletal muscle = 60:39:.7; and subcutaneous adipose = 73:20:7. Normalization of data to beta-actin transcript concentration did not change these relationships. Rat perigonadal adipose tissue beta1AR and beta3AR transcript concentrations were, respectively, .59 and 1.84 amol/microg of total RNA. The rat perigonadal adipose tissue concentration of beta3AR transcript was tenfold that of porcine subcutaneous adipose tissue. The predominant betaAR transcript in rat adipose tissue was beta3AR, and the predominant betaAR transcript in pig adipose tissue was beta1AR.