Hi, this is Dr. Maggie - I am going to answer your question today.
Cushings Disease (also called Hyperadrenocorticism) is a disease of excess cortisol. It occurs either as a result of excessive production of cortisol by the adrenal glands, as a result of an overactive pituitary gland (that promotes the release of excess cortisol from the adrenal glands), or as a result of long term excessive use of steroids.
Dogs with Cushings Disease often have a ravenous appetite, a pot-bellied appearance, increased thirst, increased urination, urinary incontinence, muscle weakness, thinning hair coat, and skin issues. (To name some of the more common symptoms.) If your dog has diabetes, he is at an increased risk of developing Cushings Disease.
If you would like to read more about Cushings Disease, you should visit the following link: http://www.veterinarypartner.com/Content.plx?P=A&C=&A=1193&SourceID=
Hopefully that answered your question. Please let me know if you have any additional questions or concerns.
If you found this information helpful, please rate this answer positively so I can get compensated for my time. Thanks and best of luck with Bobby!