INS and diabetes mellitus: However, although this feline type 2 DM is suspected to be the most common type of spontaneous DM in the cat, other types of spontaneous feline DM have also been described to occur, particularly DM as a consequence of endogenous overproduction of hormones with an insulin-antagonistic effect such as cortisol (hyperadrenocorticism or Cushing’s syndrome) and growth hormone (HS or acromegaly) [11].