5. Adrenaline (Epinephrine)
Synthesis:
Conversion from Noradrenaline:
Enzyme: Phenylethanolamine N-methyltransferase (PNMT).
Process: Noradrenaline is methylated to form adrenaline (epinephrine).
Cofactor Required: S-adenosylmethionine (SAMe) as a methyl donor.
Mechanism: The enzyme transfers a methyl group from SAMe to the amine group of noradrenaline, producing adrenaline.
Significance:
Acute Stress Response: Adrenaline enhances the body's fight-or-flight response by increasing heart rate, blood pressure, blood glucose levels, and airflow to the lungs, preparing the body for rapid action.
Clinical Relevance:
Emergency Situations: Adrenaline is crucial during acute stress or danger, helping the body respond quickly to threats.