The effect of orthotopic transplantation on total, beta 1- and beta 2-adrenoceptors in the human heart.
1. [125I]-(-)pindolol binding was used to determine beta-adrenoceptor density in homogenate preparations of right ventricular endomyocardial biopsies from 43 non-rejecting patients over the first 13 months following cardiac transplantation. The selective beta 1 subtype antagonist ligand CGP 20712A was used to determine the subtype density in 32 of the patients. Biopsy specimens from 15 donor hearts were used as controls. 2. beta-adrenoceptor density (expressed in terms of fmol mg-1 protein) was increased in the group of transplanted hearts as a whole compared with the donor hearts with respect to total (35 +/- 2 vs 23 +/- 2) and the beta 1 subtype (25 +/- 2 vs 16 +/- 2) whereas the beta 2 subtype and radioligand dissociation constant did not differ. 3. Non-parametric analysis of variance of total receptor density over time revealed significant heterogeneity which appears to be due to a discrete increase in beta-adrenoceptor density during the 4th post operative month. 4. These results indicate that beta-adrenoceptor density is not constant following transplantation. Furthermore, the increase in receptor density following transplantation is due mainly to an increase in the beta 1 subtype without a significant change in the beta 2 subtype.
Chester
M R
MR
National Heart and Lung Institute, Harefield Hospital, Leicester.
Madden
B
B
Barnett
D
D
Yacoub
M
M
D000328:Adult; D004699:Endocardium / Q000737:chemistry*; D005260:Female; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000737:chemistry*; D010869:Pindolol / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000032:analysis*
D011943:Receptors, Adrenergic, beta; D010869:Pindolol