Catecholamine-thyroid hormone interaction on myocardial ornithine decarboxylase.

Myocardial phosphorylase alpha activity responds to stimulation by catecholamines and thyroid hormone. In hyperthyroidism this enzyme is supersensitive to beta-adrenergic stimulation and blockade, indicating that its increased activity is an indirect effect of thyroid hormone. Myocardial ornithine decarboxylase (ODC) activity also responds to catecholamine and thyroid hormone stimulation.