Effect of Hormone Therapy on Renal Function

Inclusion Criteria: * Identify as transgender * Age 17-30 years (inclusive) * Plan to start gender affirming hormone therapy (testosterone or estradiol) clinically in ≤ 1 months and remain on for at least 3 months Exclusion Criteria: * Cognitive, psychiatric or physical impairment resulting in inability to tolerate the study procedures (e.g. intellectual disability, schizophrenia, hallucinations) * Type 1 or Type 2 diabetes * Chronic kidney disease, or eGFR \<60ml/min/1.73m2 by CKD-EPI formulation * Uncontrolled hypertension (resting BP ≥ 140/90 mm/Hg) * Allergy to shellfish, iodine or iohexol * Currently taking: sulfonamides, procaine, thiazolesulfone and probenecid (renal clearance measurements of PAH cannot be made accurately if individuals are on these medications) * Prior gender affirming hormone therapy use * Prior gonadectomy * Pregnancy