Testosterone Analysis in Hair

Abstract: The effects of testosterone in the body are dependent on the concentrations at the target organs, as well as the susceptibility of the androgen receptor. Steroid hormones circulate in the bloodstream bound to proteins, and only a small part is unbound and free to exert its effect at the receptors. Due to the diurnal variation in testosterone levels, the measured concentrations can change rapidly. Thus, a kind of "long-term measure" of the average free testosterone concentration would facilitate the understanding of the hormones' long-term effects on target organs.Hair seems at first sight to be a suitable matrix. The current theory is that only the free, unbound fraction of hormones passively diffuse from the bloodstream into the hair matrix as the hair grows. In this thesis, we have developed an analysis capable of analysing testosterone in the hair of men and women. We have systematically explored potential confounding factors and the pattern of testosterone concentrations in different hair segments. Furthermore, we have sought to confirm biological differences such as sex, age and BMI which affect hormone concentrations in the blood. Finally, we have investigated how hair testosterone concentrations change in relation to treatment with oral contraceptives and before an acute myocardial infarction.Our conclusions are that it is possible to measure testosterone in extracts from hair in very low concentrations. The choice of measurement method needs to balance between high specificity, which mass spectrometry can offer, and adequate detection limits, which can be achieved with immunoassays. Hair testosterone concentrations correlate significantly with testosterone concentrations in saliva, which suggests that hair testosterone reflects the average hormone concentrations in the body. The significant variation in hair growth rate within and between individuals impedes the theoretical relationship between certain hair segments and a specific time in the past. Hair testosterone concentrations are affected by the frequency of hair washing, cosmetic hair treatment, natural hair colour and the biological sex. In hair samples taken shortly after a patient was admitted to hospital due to a myocardial infarction, lower concentrations of testosterone can be seen in hair compared to individuals of the same age who have not had an acute heart attack. This suggests that a reduction in testosterone concentrations occurs shortly before the heart attack, independently of other cardiovascular risk factors. Reduced testosterone concentrations could thus be an independent risk factor for developing an acute myocardial infarction.