Male Testosterone Does Not Adapt to the Partner's Menstrual Cycle.

Background: It has not yet been established whether men in heterosexual relationships adapt their hormone levels to their female partner's menstrual cycle to allocate reproductive resources to the period when the female is actually fertile.

Aim: This prospective observational study tested the hypothesis that some males have peaks in testosterone or acne (a possible biomarker for androgen activity) near their partners' ovulation, whereas other males display the opposite pattern.

Methods: 48 couples supplied menstrual cycle data, male salivary samples, and a protocol of daily activities for 120 days.

Testosterone-like immunoreactivity in hair measured in minute sample amounts - a competitive radioimmunoassay with an adequate limit of detection.

The concentrations of testosterone deposited in hair during hair growth may provide a retrospective reflection of the concentrations of bioactive testosterone in plasma. The objective of this study was to develop a radioimmunoassay with a sufficiently low limit of detection to measure the testosterone-like immunoreactivity in smaller hair samples (5 mg) than used in earlier studies, and to compare three different extraction procedures. The competitive radioimmunoassay consisted of a polyclonal antiserum (immunogen testosterone-7α-BSA) and a radioligand synthesised from testosterone-3-CMO-histamine.