Endocrine Abstracts

Objective: To investigate performance of sex hormone binding globulin (SHBG) assays of different manufacturers and the effects of assay choice on calculated free testosterone (cFT).Methods: Anonymized serum samples of 113 men and 106 women were randomly selected from excess material from the routine clinical lab at the University Hospital of South Manchester. SHBG levels were measured using three different immunoassays (...

Introduction: Although it is well-known that serum testosterone (T) levels decrease in ageing men, to this date no longitudinal data are available on changes in T levels in healthy young adult men.Objective: To investigate age-related longitudinal changes in serum levels of total T, free T and sex hormone binding globulin (SHBG) in healthy young men.Methods: Data from 999 healthy men aged 24–46years who participated in a long...

Background: Investigating longitudinal changes in serum androgen levels in healthy men in relation to (changes in) body composition, lifestyle factors and intercurrent illnesses.Methods: Longitudinal observational study. 999 healthy men aged 24–46 years of whom 691 were re-evaluated after a mean period of 12 years. Serum SHBG, luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were measured using immuno-assays. Testosterone (T), ...

Introduction: Determination of serum (calculated) free testosterone (FT) in clinical practice has been suggested by several clinical guidelines for the diagnosis of male hypogonadism in men with borderline total T concentrations and in situations with altered sex hormone-binding globulin, as it correlates better with androgen exposure than total T. The gold-standard for the determination of FT levels is considered to be directly measured free testosterone (mFT) using equilibri...

Introduction: According to the free hormone transport hypothesis, only free testosterone (FT) is considered biologically active. Due to low circulating levels and technical challenges of direct FT measurements, calculators have been developed to estimate FT from serum total T, sex hormone-binding globulin (SHBG) and albumin levels. However, genetic polymorphisms altering SHBG’s binding affinity or capacity might result in calculation imprecisions with consequent incorrect...

Introduction: Transgender women on gender-affirming hormone therapy (GAHT) with estrogens and anti-androgens have low serum androgen levels. These low levels may be associated with clinical symptoms such as depressed mood, reduced sexual desire and tiredness. Whether androgen levels change over the course of anti-androgen use and after gonadectomy, in a context of unchanged estrogen treatment, remains to be elucidated.Methods: This study is part of the E...