The most common and most likely answer to this crossword clue is the 10 letter word ADRENALINE
I've seen this crossword clue in Independent
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More clues leading to the result ADRENALINE
- One to quit troubled Dáil Eireann — that causes rush!
- Hormone replacement initially covered in a study leading to some dishonest statement
- Medicwearing type of garment is something to get the pulse racing!
- Excitement of a geek about some cocaine
- A geek coming up interrupts a row? It raises one’s blood pressure
- Endless denial about injecting of kidney hormone
- A doctor and nurse have a row to provide a kind of internal release?
- Medic in A&E beginning to need some cocaine in response to stress
- Ace Doctor Sharples approach: a shot in the arm?
- Topless Brenda flinging such a skirt — it gets the pulse racing
Buddy explains!

The straight part
We know that "a kind of internal release?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a kind of internal release? = adrenaline.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ADRENALINE mean?
ADRENALINE noun- Epinephrine, the hormone and neurotransmitter.