Hormone from kidneys -- there's a row about that (9)
I believe the answer is:
adrenalin
'hormone' is the definition.
(adrenalin is a kind of hormone)
'kidneys there's a row about that' is the wordplay.
'kidneys there' becomes 'renal' (I can't justify this - if you can you should give a lot more credence to this answer).
'row' becomes 'din' (both can mean a loud disturbance).
'about that' means one lot of letters goes inside another.
'a'+'din'='adin'
'renal' going into 'adin' is 'ADRENALIN'.
'from' acts as a link.
Can you help me to learn more?
(Other definitions for adrenalin that I've seen before include "Hormone secreted in response to fear" , "Stimulating hormone" , "Metabolism-affecting hormone" , "Hormone affecting metabolism" , "Hormone secreted in response to stress" .)