Effects of Testosterone Undecanoate as a Male Contraceptive Candidate on Rat Immunological Features

AbstractTestosterone undecanoate (TU) is under phase III clinical trial as a hormonal male contraceptive in China. Sex hormones can modulate the immune system. Female hormonal contraceptives may affect SIV/HIV‐1 transmission. To evaluate the safety of TU and to understand whether long‐term use of TU for a male contraceptive affects users' immunological features, adult male rats were treated for a 32‐week TU‐treated phase at the dose of 20 mg TU/kg body weight and a 24‐week recovery phase. The reproductive and immunological parameters of 4–6 rats in each subgroup were examined at the stated time point. The mean sperm count and viability in the treated rats were significantly suppressed (p < 0.01). In the TU‐treated group: the mean blood leukocyte and lymphocyte counts; the proliferation indexes of T cells from peripheral blood mononuclear cells (PBMC) and spleen; and, of B cells from spleen, as well as the mean counts of blood T, NK, and B cells decreased in comparison with those of control group. These de...