Investigating the Stability, Variability and Mechanism of Incorporation of Lipid Mediators Into Eccrine Sweat

The purpose of this study is to see what the differences are in sweat (amount and small molecule content) collected from different sites of the body and by different methods of sweat stimulation. Additionally, the investigators want to know whether the amount and small molecule content of the sweat is the same in an individual over time, and the same across individuals at a given time. Finally, the investigators want to know how consumption of over-the-counter anti-inflammatory drugs such as ibuprofen will affect the inflammatory mediator content of sweat and how that compares to blood. This information will help to better understand the composition and behavior of sweat and assess its potential utility as a routine clinical tool in skin research.

Subjects will participate in 4 study day visits that will be scheduled about 1- week apart. During the first study visit, the investigators will compare sweat collected following pharmacological stimulation of sweating (using the drug pilocarpine) to sweat collected following physiological stimulation of sweating (using a stationary bicycle). During the second study visit, the investigators will collect sweat following stimulation of sweating by the drug pilocarpine from the inner part of the forearm (near the wrist) and also the upper surface of the thigh (near the knee). During the third study visit, the investigators will collect sweat following stimulation of sweating by the drug pilocarpine from the inner part of both forearms (near the wrist). During the fourth study visit, the investigators will collect a sweat sample following stimulation of sweating by the drug pilocarpine from the inner part of the forearm (near the wrist) and a blood sample (about one teaspoon) from the other arm. After blood and sweat collection, participants will consume 400 mg (two tablets) of ibuprofen. The investigators will then collect blood and sweat from 30 minutes, 2 hours and 4 hours after participants consume the ibuprofen.

Eligibility Criteria:
Inclusion Criteria:

* 20-40 y
* Male
* Weight \> 110 pounds

Exclusion Criteria:

* Diagnosed active chronic diseases for which the individual is currently taking daily medication, including but not limited to:

  * Diabetes mellitus
  * Cardiovascular disease
  * Cancer
  * Gastrointestinal disorders
  * Kidney disease
  * Liver disease
  * Bleeding disorders
  * Asthma
  * Autoimmune disorders
  * Hypertension
  * Osteoporosis
* Recent minor surgery (within 4 wk) or major surgery (within 16 wk)
* Recent antibiotic therapy (within 4 wk)
* Recent hospitalization (within 4 wk)
* Use of over-the-counter or prescription medications at the time of the study that directly affect endpoints of interest (e.g. hyperlipidemia, glycemic control, steroids, statins, anti-inflammatory agents, and weight loss aids)
* Adults who are not able to consent
* Under current medical supervision
* Ibuprofen intolerance or allergy
* Those with a bleeding disorder
* Current enrollee in a clinical research study.
* Individuals with blood clotting or platelet defect disorders
* Individuals with orthopedic limitations or cardiovascular risk that preclude participation in the physiological stimulation of sweat by light exercise portion of the study
* Individuals who are trained athletes or that regularly perform physical activity defined as "vigorous" by the Centers for Disease Control and Prevention