[Stimulating effect of glucagon and theophylline on the activity of rat liver betamine-homocysteine-methyltransferase. Role of cyclic adenosine-3',5'-monophosphate].

Effect of glucagon, theophylline, NaF and cyclic 3',5'-AMP on the activity of betaine-homocysteine-methyl transferase (BHMT) was studied in homogenates of rat liver tissue. Intraperitoneal administration of theophylline into adult rats increased the BHMT activity in liver tissue. After administration of theophylline the BHMT activity was distinctly increased in liver tissue within 2 hrs, approaching the maximal value within 3 hrs after which it decreased quickly up to 5-6 hrs. Intraperitoneal administration of glucagon into adult rats also increased the BHMT activity; theophylline, administered simultaneously with glucagon, potentiated the effect of the latter on the BHMT activity in liver tissue. Administration of glucagon into rat embryos 1-2 days before the birth was accompanied by a 2-fold increase in the BHMT activity. In the in vitro experiments theophylline (10(-6)-10(-5) M) showed the stimulating effect on the liver tissue BHMT activity. Dibutyryl adenosine-3,5'-cyclic phosphate and NaF caused the variable effect on the BHMT activity in liver tissue of adult rats. Administration of cyclic-3',5'-AMP (5 mg per 100 g of body weight) decreased the BHMT activity in liver tissue mitochondria and increased 2.5-fold the enzyme activity in cytosole.