"ISIS" Study of Sex Differences in Characteristics of Adiposity and Metabolism

Study of Sex Differences in Characteristics of Adiposity and Metabolism

The purpose of this study is to characterize differences in the structure and function of the body fat from two different parts of the body in young, healthy men and women. We will also compare how differences in metabolism relate to characteristics of body fat and its functions.

Following screening, the study comprises of a total of 3 clinic visits (2 outpatient visits, and 1 overnight stay) completed during a 2 week period. For the outpatient visits, body composition (by DEXA), visceral fat (by CT), ectopic fat (by MRS and CT) and aerobic fitness (by VO2max test) will be measured. Women will also have ovarian parameters (follicle size and number) measured during the MR scans. Following an overnight stay in the inpatient unit, insulin sensitivity (by euglycemic hyperinsulinemic clamp), interstitial lipolysis (by microdialysis), whole body lipolysis and glycolysis (by stable isotopes), abdominal adipose tissue oxygen content (Hunt and Direct Methods) will be measured and a subcutaneous fat biopsy of the abdominal and gluteo-femoral tissue will be collected. Women will complete all testing in the follicular phase of the menstrual cycle.

Inclusion Criteria:

• Diabetic men and women ages 40 to 60, inclusive and healthy men and women ages 20 to 35, inclusive.
• Body mass index (a ratio of height to weight) less than 25 kg/m2 (lean group) or 27 to 35 kg/m2 (overweight/obese group).
• Not involved in regular physical activity (more than 3 times per week).
• Women must have regular menstrual cycles (1 menstrual bleeding each month).

Exclusion Criteria:

• For men in the overweight/obese group, you have a waist circumference less than 102cm (40 inches).
• You smoke.
• You have liver, kidney, thyroid or heart diseases, or cancer.
• You are claustrophobic.
• You have metal objects in your body such as implanted rods or surgical clips.
• If you are not diabetic and you are taking steroids, protease inhibitors, statins, antihypertensives or medications known to alter glucose or lipid metabolism.
• If you are diabetic and you are taking steroids, protease inhibitors, or injectable antihyperglycemic medications (oral diabetic meds are allowed.)
• If you are a woman, you are pregnant or breast feeding or trying to become pregnant (women who become pregnant throughout the study will be excluded).
• If you are a woman, you are using hormonal contraceptives or have anovulation, androgen excess or irregular menstrual cycles (less than 1 cycle per month).
• You have previously had a BMI >35 kg/m2.
• You are not able to eat the foods provided by PBRC.
• If your weight has not been stable.