Beta-adrenoceptor changes in mononuclear leukocytes during pregnancy.
Leukocyte beta 2-adrenoceptors mirror similar receptors in the uterus. This study examined changes in beta 2-adrenoceptors and in cAMP production during pregnancy using peripheral mononuclear leukocytes isolated from 17 pregnant women and 5 nonpregnant controls. beta 2-Adrenoceptor density was determined by 125I-pindolol binding. cAMP production under basal and stimulated (10 microM isoproterenol) conditions was determined by radioimmunoassay. Groups were compared by unpaired t test. There was a nonsignificant decrease in the density of beta-adrenoceptors during pregnancy. While basal cAMP production was unchanged during pregnancy, stimulated cAMP production was decreased (44% of control, P < 0.001; 95% CI 33%-56%). Stimulated cAMP production per receptor was lower in leukocytes from pregnant women and was not a constant relationship, but was increased markedly in leukocytes having fewer than 400 beta-adrenoceptor sites per cell. There are significant changes in the coupling of beta-adrenoceptors to cAMP production during pregnancy without changes in beta-receptor density, affinity, or basal cAMP production.
Nwosu
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Department of Obstetrics and Gynecology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614, USA.
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D000328:Adult; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D010869:Pindolol / Q000378:metabolism; D011247:Pregnancy; D011869:Radioligand Assay; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D015398:Signal Transduction
D011943:Receptors, Adrenergic, beta; D010869:Pindolol; D000242:Cyclic AMP