The purpose of this study is to describe drug concentrations in blood plasma, rectal fluid, rectal tissue, and seminal fluid in HIV negative men following single and multiple doses of an investigational HIV medication known as GSK1349572 (dolutegravir).

The purpose of this study is to determine first dose and steady-state concentrations of GSK1349572 in seminal fluid, rectal mucosal fluid, and rectal tissue compared to blood plasma (BP) in HIV-1 negative males. GSK1349572 is an investigational next generation integrase inhibitor currently in Phase III trials. Understanding the concentrations of GSK1349572 in multiple male biological compartments will inform its role in preventing HIV infection by making an HIV-infected person less likely to transmit the virus, and protecting uninfected persons from acquiring the virus.

Inclusion Criteria:

• Healthy male subjects between the ages of 18 and 49 years, inclusive, with intact genital tract and gastrointestinal tract.
• Body Mass Index (BMI) of 18 to 30 kg/m2; and a total body weight greater than 50 kg (110 lbs).
• Evidence of a personally signed and dated informed consent document
• Willing and able to comply with all scheduled visits, treatment plan, laboratory tests, and other trial procedures.

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease
• Subjects with a history of gastrectomy, colostomy, ileostomy, or any other procedure altering the gastrointestinal tract.
• Subjects with a history of vasectomy, prostatectomy, or any other procedure altering the male reproductive tract.
• Subjects with inflammatory bowel diseases (ulcerative colitis or Crohn's disease), irritable bowel syndrome, or other abnormalities of the colorectal mucosa, or significant colorectal symptom(s)
• Subject who is unwilling to refrain from any sexual activity for 72 hours before study visit Day 0 and until discharge from the study.
• Subject who is unwilling to refrain from rectal insertion of medical/recreation devices and products and from receptive anal intercourse, for 72 hours before study visit Day 0 and through 7 days after the last biopsy.
• History of febrile illness within 14 days prior to the first dose.
• Any condition possibly affecting drug absorption (eg, gastrectomy).
• A positive urine drug screen.
• A positive result for HIV, Hepatitis B surface antigen or Hepatitis B core antibody screening tests or anti-hepatitis C virus serology
• A positive test for syphilis, rectal gonorrhea, chlamydia, or HSV-2 (active lesions) at screening.
• Current alcohol consumption exceeding 14 drinks [1 drink = 5 ounces (150 mL) of wine or 12 ounces (360 mL) of beer or 1.5 ounces (45 mL) of spirits] per week or unwilling to abstain from alcohol use from 48 hours prior to the first dose of study medication until after the follow-up visit.
• History of regular use of tobacco- or nicotine-containing products exceeding an equivalent of 5 cigarettes per day within three months prior to screening or unwilling to abstain from cigarette smoking completely during visits.
• Treatment with an investigational drug within 4 months preceding the first dose of trial medication.
• Participated in a rectal biopsy study in the 12 months preceding the first dose of trial medication.
• Use of clinically significant prescription or non-prescription drugs within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication
• Blood donation of approximately 1 pint (≥473 mL) within 56 days prior to dosing.
• History of sensitivity to heparin or heparin-induced thrombocytopenia.
• History of confirmed allergy to prescription or non-prescription products.
• Unable or unwilling to swallow oral medications.
• History of bleeding or clotting disorders including disseminated intravascular coagulation, hemophilia Henoch-Schönlein purpura (allergic purpura), hereditary hemorrhagic telangiectasia, thrombocytopenia, thrombophilia or Von Willebrand's disease.
• The subject's blood pressure is outside the range of 90-140/45-90 mmHg, or heart rate is outside the range of 45-100 bpm.
• Clinically significant abnormalities to pulse or conduction observed on ECG
• Unwilling or unable to comply with dietary restrictions
• Any other reason or condition that would make participation in the study unsafe, complicate interpretation of study outcome data, or interfere with achieving the study objectives.