The effect of isoproterenol on pyrimidine biosynthesis in the salivary gland and heart of rats.

SummaryMultiple injections of isoproterenol (ISO) (5 mg/kg, s.c.) administered twice daily to rats increased wet tissue weight, total RNA content, and the incorporation of 14C-labeled amino acids into protein of heart and submaxillary glands. The activities of aspartic transcarbamylase and orotidine-5′-phosphate pyrophosphorylase-decarboxylase (measured together) were enhanced in submaxillary glands and in hearts. Dihydroorotase activity could not be detected in heart but was enhanced in the salivary glands taken from rats treated with ISO. These enzymes are considered to be involved in pyrimidine biosynthesis. Incorporation of uridine-3H into salivary gland and heart RNA was enhanced after 2 doses of ISO but then decreased to control (salivary gland) or to below control (heart) with more prolonged ISO treatment