Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
For general information about clinical research, read Learn About Studies.
Eligibility Criteria
- * Male, age 18-65 years
- * Willing and able to provide informed consent and follow all study procedures, including providing sperm specimens 3 months apart.
- * Type 1 or type 2 diabetes diagnosis confirmed by an endocrinologist (for participants in the diabetes groups)
- * HbA1c \> 7% (for participants in the diabetes groups)
- * Overweight (BMI \> 25 kg/m2) (for all groups, to ensure groups are similar)
- * Chronic kidney disease stage 4 or 5 (including end-stage renal disease);
- * Hepatic disease, including serum alanine transaminase (ALT) or aspartate aminotransferase (AST) greater than or equal to 3 times the upper limit of normal; hepatic synthetic insufficiency as defined as serum albumin \< 3.0 g/dL; or serum bilirubin \> 2.0;
- * Severe diabetic retinopathy;
- * Congestive heart failure, New York Heart Association (NYHA) class II, III or IV;
- * History of myocardial infarction, unstable angina or revascularization within the past 6 months;
- * Active genitourinary infection;
- * Testicular volume \<12 mL (assessed using Prader orchidometer);
- * Hypogonadism, defined as total testosterone \<250 ng/dl;
- * Hyperprolactinemia, defined as prolactin \>18 ng/ml;
- * Hyperestrogenism, defined as estradiol \>42 pg/ml;
- * Cryptorchidism;
- * Cigarette smoking;
- * Active alcohol abuse or substance abuse;
- * Cancer (except localized non-melanoma skin cancers) or use of chemotherapy agents within 5 years;
- * Use of nitrates or guanylate cyclase stimulators;
- * Use of steroid hormones (including testosterone), other than inhalers for reactive airway disease
Ages Eligible for Study
18 Years to 65 Years
Sexes Eligible for Study
MALE
Accepts Healthy Volunteers
Yes