Summary
The β-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 β-adrenergic receptor number was seen in patients
with IDDM (Bmax = 27.6±8.3 fM (125l) IHYP/mg protein) compared with normal children
(Bmax = 40.4±10.4 fM (1251) IHYP/mg protein) and normal adults (Bmax = 36.9±6 f M
(1251) IHYP/mg protein). MNL β-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 β-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 β-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.
Key-Words
Insulin Dependent Diabetes Mellitus
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Catecholamine
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Glycosylated Hemoglobin
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β-Adrenergic Receptor
