Effect of propranolol and pindolol on the up-regulation of lymphocytic beta adrenoceptors during acute submaximal physical exercise. A placebo-controlled double-blind study.
The effect of beta-adrenoceptor antagonists, with and without intrinsic sympathomimetic activity, on the regulation of lymphocytic beta adrenoceptors during acute physical exercise was studied. Seven healthy volunteers underwent a graded maximal ergometer test after treatment for 7 days with placebo, propranolol (2 x 80 mg/day), or pindolol (2 x 10 mg/day). Each subject received the three types of drug treatment in a double-blind, randomized fashion, with 3 weeks wash-out periods between the on-drug periods. The mean resting density of lymphocytic beta adrenoceptors was 46 +/- 5 fmol/mg protein (mean +/- SEM) during placebo, 53 +/- 5 fmol/mg protein during propranolol, and 29 +/- 4 fmol/mg protein during pindolol treatment (p less than 0.05, pindolol vs. propranolol). Exercise induced a significant up-regulation of the beta-adrenoceptor density during each treatment modality, but the increment was attenuated during propranolol (mean elevation, 16 +/- 2 fmol/mg protein, p less than 0.05) and pindolol intake (13 +/- 4 fmol/mg protein, p less than 0.02) as compared with the placebo value (56 +/- 13 fmol/mg protein). Moreover, exercise-induced increment of lymphocytic cyclic AMP (cAMP) production was virtually abolished by the two beta-adrenoceptor antagonists. In conclusion, administration of beta-adrenoceptor antagonists is associated with a subnormal up-regulation of the lymphocytic beta-adrenoceptors and alterations in their functioning during heavy physical effort. This attenuation is not modified by intrinsic sympathomimetic activity of the compound.
Mäki
T
T
Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland.
Näveri
H
H
Leinonen
H
H
Sovijärvi
A
A
Lewko
B
B
Härkönen
M
M
Kontula
K
K
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D000242:Cyclic AMP / Q000097:blood; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007773:Lactates / Q000097:blood; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion; D010869:Pindolol / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D011897:Random Allocation; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D015854:Up-Regulation / Q000187:drug effects
D007773:Lactates; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D010869:Pindolol; D000242:Cyclic AMP; D009638:Norepinephrine; D004837:Epinephrine