The monoamines dopamine and serotonin v. glucocorticoids as the first regulators of stress

Sapolsky in this superb article discusses the damage that uncontrolled stress can do. He promotes the mainline hypothesis that corticosteroids are the primal regulators. I think there is a far more primitive reciprocal regulatory system:

• The structures of both levodopa and serotonin are far simpler than glucocorticoids. 
• The metabolite pathways for both monoamines are far simpler; both are only 2 steps from essential amino acids. 
• Both TYRosine and TRYptophan are first hydroxylated and then decarboxylated to achieve their endpoints, DA and 5-HT. 
• The enzymes for both are either identical (L-aromatic amino acid decarboxylase) or were identical in the past.