TY - JOUR
T1 - Effect of thyroid status on α- and β-catecholamine responsiveness of hamster adipocytes
AU - Garćia-Sáinz, J. Adolfo
AU - Litosch, Irene
AU - Hoffman, Brian B.
AU - Lefkowitz, Robert J.
AU - Fain, John N.
PY - 1981/12/18
Y1 - 1981/12/18
N2 - It has been suggested that part of the increased β-catecholamine responsiveness in hyperthyroid animals is due to a decrease in α-catecholamine action. The present results indicate that neither hyperthyroidism nor hypothyroidism altered the α2-adrenergic inhibition of adenylate cyclase or the α1-adrenergic stimulation of phosphatidylinositol turnover in adipocytes from the white adipose tissue of hamster. No effect of hyperthyroidism was found on the Kd of [3H]dihydroegocryptine or the number of binding sites in membranes prepared from hamster adipocyte tissue. The stimulation of cyclic AMP due to β-catecholamines was enhanced in adipocytes from hyperthyroid hamster, as was lipolysis. However, in adipocytes from hyperthyroid hamster the maximal stimulation of cyclic AMP due to isoproterenol, ACTH or epinephrine plus yohimbine, as seen in the presence of adenosine deaminase and theophylline, was less than in adipocytes from euthyroid hamsters. The activation of adenylate cyclase by isoproterenol was the same in membranes from hyperthyroid as compared to those from euthyroid hamsters in the absence or presence of guanine nucleotides. These data suggest that thyroid status has little effect on α-catecholamine action but enhances the activation of lipolysis by β-catecholamine agonists.
AB - It has been suggested that part of the increased β-catecholamine responsiveness in hyperthyroid animals is due to a decrease in α-catecholamine action. The present results indicate that neither hyperthyroidism nor hypothyroidism altered the α2-adrenergic inhibition of adenylate cyclase or the α1-adrenergic stimulation of phosphatidylinositol turnover in adipocytes from the white adipose tissue of hamster. No effect of hyperthyroidism was found on the Kd of [3H]dihydroegocryptine or the number of binding sites in membranes prepared from hamster adipocyte tissue. The stimulation of cyclic AMP due to β-catecholamines was enhanced in adipocytes from hyperthyroid hamster, as was lipolysis. However, in adipocytes from hyperthyroid hamster the maximal stimulation of cyclic AMP due to isoproterenol, ACTH or epinephrine plus yohimbine, as seen in the presence of adenosine deaminase and theophylline, was less than in adipocytes from euthyroid hamsters. The activation of adenylate cyclase by isoproterenol was the same in membranes from hyperthyroid as compared to those from euthyroid hamsters in the absence or presence of guanine nucleotides. These data suggest that thyroid status has little effect on α-catecholamine action but enhances the activation of lipolysis by β-catecholamine agonists.
KW - (Hamster adipocyte)
KW - Catecholamine responsiveness
KW - Thyroid state
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U2 - 10.1016/0304-4165(81)90112-4
DO - 10.1016/0304-4165(81)90112-4
M3 - Article
C2 - 6274417
AN - SCOPUS:0019814690
VL - 678
SP - 334
EP - 341
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
SN - 0304-4165
IS - 3
ER -