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.
Department of Clinical Chemistry, University of Helsinki, Helsinki, Finland.
T
T
Mäki
H
H
Näveri
H
H
Leinonen
A
A
Sovijärvi
B
B
Lewko
M
M
Härkönen
K
K
Kontula
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