separate mechanisms. Isoproterenol and 4-methyl-catechol induced NGF and NGF mRNA
in mouse fibroblast L929 cells in either the presence or absence of serum. Propranolol
prevented NGF induction by isoproterenol, but not by 4-methylcatechol or serum. All
possible combinations of these inducers resulted in additive increases in the levels of NGF
and NGF mRNA.