lack of recruitment

The purpose of this research is to find out if hormone therapy in transgender subjects' changes hormone receptors in blood, muscle and fat; fat production; muscle production; and inflammation processes.

Throughout recorded history, some men and women have experienced emotional distress at being physically "trapped" in wrong gender. Gender incongruence refers to the state where one's internal sense of gender differs from the gender assigned at birth. Advances in psychology and in our understanding of human sexuality have permitted the recognition of gender incongruence (also called transgender) as a biological phenomenon. The acceptance by the society has led to an expansion of health care services available to these individuals for supportive treatment. Gender affirming hormone therapy, usually provided by endocrinologists, is pivotal for the transition of these individuals into their desired gender. This therapy typically consists of testosterone or estrogen (male and female sex hormones) to transition into transmen or transwomen, respectively. The hormone treatment results in a "second puberty", wherein biological men receiving estrogen gain fat around hips and thighs, lose muscle and develop breasts. Biological women receiving testosterone lose fat, gain muscle, stop having menses and develop a deeper voice. However, our knowledge of the mechanisms of these hormones at the tissue level in transgender population is lacking. In this study, we plan to evaluate

1. hormone receptors that carry out the action of sex hormones in fat tissue and mononuclear cells (a type of immune cell in blood) following gender affirming therapy.
2. the mechanism that lead to growth or suppression of fat mass or lean mass
3. effect on inflammation (a cardiovascular risk marker) The hormone treatment of gender incongruence is a relatively untested therapy. The treatment is based on extrapolations and assumptions from hormone treatment in hypogonadal (hormone deficient) in cis-gender (same gender, no incongruence) individuals. We expect that our mechanistic studies will initiate an understanding into the actions of transgender therapy at the cellular level.

Inclusion Criteria:

• Diagnosed with gender incongruence by a mental health professional and willing to start gender affirming therapy

Exclusion Criteria:

• Used hormone therapy in last 6 months,
• Pregnancy,
• Planning to have biological children in the next one year,
• HIV Additional exclusion criteria for transmen: 1) hematocrit >50% for transmen, 2) transmen with allergy to cottonseed oil (component of intramuscular testosterone injection), 3) uncompensated heart failure, 4) renal failure Additional exclusion criteria for transwomen: 1) allergy to castor oil (component of intramuscular estradiol injection), 2) Known or suspected estrogen-dependent neoplasia, 3) Active deep vein thrombosis, pulmonary embolism or a history of these conditions, 4) Active or recent (e.g., within the past year) arterial thromboembolic disease (e.g., stroke, myocardial infarction), 5) Liver enzymes (AST or ALT) >3 times the upper limit of normal, 6) Known or suspected pregnancy

2 groups based on gender identity: transowmen and transmen

We plan to conduct a prospective, open label study in individuals initiating gender affirming therapy for gender incongruence. We will recruit 20 transmen and 20 transwomen in this study.