Adaptive regulation of beta-adrenergic receptors in children with insulin dependent diabetes mellitus.
The beta-adrenergic receptors were investigated in partially purified mononucleal leukocytes (MNL) plasma membranes from 18 patients with IDDM in pediatric period, 9 healthy children and 8 normal adults. The decreased beta-adrenergic receptor number was seen in patients with IDDM (Bmax = 27.6 +/- 8.3 fM (125I) IHYP/mg protein) compared with normal children (Bmax = 40.4 +/- 10.4 fM (125I) IHYP/mg protein) and normal adults (Bmax = 36.9 +/- 6 fM (125I) IHYP/mg protein). MNL beta-receptor binding affinities (apparent Kd = 109.8 +/- 26.1 pM in IDDM, 102.8 +/- 46.6 pM in normal children, 130.0 +/- 43.1 pM in normal adults) did not differ. We divided the patients with IDDM into two groups based on their level of blood glycosylated hemoglobin (HbA1) when samples were taken. Group A IDDM (consisted of 9 diabetic patients with below 10% of HbA1) had markedly decreased beta-receptor numbers compared with group B IDDM (consisted of 9 diabetic patients with more than 10% of HbA1), whereas Kd was not significantly different. Also, there was negative correlation between Bmax and level of blood sugar or HbA1 in IDDM. This is the first report concerning the beta-adrenergic receptor in IDDM in pediatric period. We suggest that decreased Bmax in group B is a homeostatic response to restore the poorly-controlled hyperglycemic state to normoglycemia because the group B patients had high level of HbA1 and blood sugar.
D000293:Adolescent; D000328:Adult; D002462:Cell Membrane / Q000378:metabolism; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D009000:Monocytes / Q000378:metabolism; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D006442:Glycated Hemoglobin; D010869:Pindolol; D011943:Receptors, Adrenergic, beta; C011878:iodohydroxybenzylpindolol