Study of the beta1 adrenergic receptor expression in human tissues: immunological approach

Questions exist regarding tissue distribution of the beta1 adrenergic receptor (beta1-AR). The aim of this study was to investigate relative distribution patterns of the beta1-AR at the protein level in a variety of human tissues by Western blot analysis. The specificity of anti-peptide antibodies was confirmed both by Western blot with recombinant beta1-AR expressed as a membrane protein in E. coli and by immunoprecipitation of membranes from Sf9 cells infected with baculovirus to express the human recombinant beta1-AR. beta1-AR was found in all tissues examined. The relative amount of protein varied significantly between the tissues, from highest in lung and testis to very low in liver. beta1-ARs were rather abundant in heart, kidney, placenta, spleen and thyroid. These results reveal unique distribution of beta1-AR protein that suggests its tissue specific role. Moreover, our data demonstrate a high sensitivity of immunological detection that allows direct comparison of beta1-AR subtype expression and could be used for receptor study in biopsies available in limited amounts, such as human heart biopsy.