Suppression of spermatogenesis by testosterone undecanoate-loaded injectable in situ-forming implants in adult male rats

Abstract

We have investigated the feasibility of administration of testosterone undecanoate (TU)-loaded injectable in situ-forming implant (ISFI) for contraception in adult male Sprague–Dawley rats. Male rats were treated with vehicle, TU-loaded ISFIs (540, 270 and 135 mg TU kg−1) or TU injections (45 mg TU kg−1 every 30 days) for 120 days. Fertility tests served for determining infertility or restoration of fertility in treated rats. Serum testosterone concentration, epididymal sperm count, motility, morphology, and histology of the testis were monitored. The TU-loaded ISFIs increased serum testosterone levels in rats steadily without fluctuation over 3 months. One month after TU administration, the epididymal sperm count decreased significantly in all experimental groups. After 3 months, the animals treated with 270 and 135 mg kg−1 TU-loaded ISFIs were 100% infertile, and no implantation sites were produced in the mated females. However, some of males treated with 540 mg kg−1 ISFI or TU injections were still fertile but numbers of implantation sites were also significantly lower than control values. TU-loaded ISFI at an appropriate dose has potential as a long-acting male contraceptive drug that suppresses spermatogenesis consistently over a period of 3 months.

The opposite effects of nandrolone decanoate and exercise on anxiety levels in rats may involve alterations in hippocampal parvalbumin–positive interneurons

“…It has been reported that prolonged ND treatment resulted in decrease of serum T in rats [ 44 – 46 ], and mice [ 47 ]. However, the elevation of serum T level observed in this study is in line with numerous reports that confirmed T levels increase following both acute [ 48 ] and chronic [ 49 – 52 ] AASs (ND and other testosterone derivatives) administration in rats. The elevation of T in rat serum, as observed in this study, could be explained by increase in T production due to stimulation of endogenous production in Leydig cells [ 53 ].…”

The Impact of Hippocampal Sex Hormones Receptors in Modulation of Depressive-Like Behavior Following Chronic Anabolic Androgenic Steroids and Exercise Protocols in Rats

“…As shown in Figure 3, all applied protocols significantly increased serum levels of T. The AASs-induced increase in T concentrations observed in this study is in line with the reported elevation of serum T following both acute (Minerly et al, 2010) and chronic (Takahashi et al, 2004; Zhang et al, 2016) administration of various AASs, which may be a consequence of up-regulated endogenous production in Leydig cells (Pomara et al, 2016). Interestingly, the exercise protocol, as well as chronic treatment with ND, did not significantly increase serum DHT levels, while TE administration in both sedentary and exercise groups resulted in elevated DHT levels in serum.…”