A Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of MK-5823 in Overweight or Obese Participants Who Are Healthy or Have Type 2 Diabetes Mellitus (MK-5823-002 AM1)

Inclusion Criteria:

- Male or female of non-childbearing potential

- A Body Mass Index between 27 and 35 kg/m^2 and weighs at least 50 kg

- Judged to be in good health and for the T2DM Panels, good health other than the
diagnosis of T2DM

- For T2DM Panels only: has a diagnosis of T2DM and is being treated with lifestyle
management (e.g. diet and exercise) alone or in combination with a stable dose of
metformin

- A nonsmoker and/or has not used nicotine or nicotine-containing products for at least
approximately 6 months

Exclusion Criteria:

- History of stroke, chronic seizures or major neurological disorder

- History of clinically significant gastrointestinal, cardiovascular, hematological,
hepatic, immunological, renal, respiratory, or genitourinary abnormalities or
diseases.

- History of clinically significant endocrine abnormalities or diseases (including type
I or type II, or steroid-induced diabetes for healthy participant panel; and
excluding T2DM for the T2DM Panels)

- Irritable bowel syndrome, or recurrent nausea, vomiting, diarrhea, or abdominal pain.

- History of neoplastic disease

- History of cataracts, diabetic retinopathy, macular edema, macular degeneration,
vitreous hemorrhage, glaucoma, ocular surgery, ocular trauma or blindness

- Requires treatment with systemic or ocular corticosteroids

- For T2DM Panels, a history of hypoglycemic unawareness

- For T2DM Panels, active treatment with any anti-hyperglycemic drug other than
metformin

- For T2DM Panels, treatment with any peroxisome proliferator-activated receptor-gamma
agonist (e.g. Avandia or Actos) within 12 weeks of study participation

- Unable to refrain from using any medication beginning 2 weeks before study
participation

- Consumes excessive amounts of alcohol (>3 per day)

- Consumes more than 6 caffeinated beverages per day

- Had major surgery or donated or lost more than 1 unit of blood

- Participated in another investigational study within 4 weeks of study participation

- History of significant multiple and/or severe allergies or anaphylactic reaction

- Hypersensitivity to glucagon or insulin

- Uses illicit drugs or has a history of drug or alcohol abuse within 3 months of study
participation

- Woman of child-bearing potential or is a nursing mother

- For T2DM Panels, age >50 years