Debate is involving disease (8)
I believe the answer is:
diabetes
'disease' is the definition.
(diabetes is a kind of gland disease)
'debate is involving' is the wordplay.
'involving' is an anagram indicator.
'debate'+'is'='debateis'
'debateis' with letters rearranged gives 'DIABETES'.
(Other definitions for diabetes that I've seen before include "Disorder causing excessive urination" , "Disease -- a side bet (anag)" , "illness" , "Disease marked by high blood glucose levels" , "Insulin-related disorder" .)