Question

what is the difference between adrenaline and noradrenaline hormone secreted by adrenal gland?

Answer 1

Adrenaline is a breakdown product of Noradrenaline. Both are produced within chromaffin cells of the adrenal medulla.  

Tyrosine is the starter molecule for both. It is broken down in the cytoplasm to form DOPA, which in turn is broken down into dopamine. Dopamine is then taken up into the granules where it is broken down into noradrenaline (in the presence of the enzyme catalyst Dopamine-B-hydroxylase).

15% of the noradrenaline produced is stored for release. The rest re-enters the cytoplasm where it is further broken down into adrenaline in the presence of PEA-N-methyltransferase. It is then taken back up for storage in the granules, ready for release.

The release of both is stimulated by the sympathetic nervous system (NA released directly from sympathetic ganglia, adrenaline being released from the adrenal glands under stimulation from the sympathetic nervous system).

Adrenaline tends to act more strongly on beta receptors (e.g. lipolysis, incr. insulin secretion, incr. heart rate, incr. arteriolar dilation - therefore decr. BP)

NA tends to act more strongly at alpha receptors (e.g. decr. insulin secretion, arteriolar constriction - therefore incr. BP, sphincter contraction, sweating, pupil dilation)

Both act to increase glycogenolysis, gluconeogenesis and cardia contraction (as these are stimulated by both alpha and beta receptors)

Answer 2

Noradrenaline and adrenaline are catecholamines. Noradrenaline is the main neurotransmitter of the sympathetic nerves in the cardiovascular system. Adrenaline is the main hormone secreted by the adrenal medulla.

hope it helps you...