Effects of velvet antler polypeptide on sexual behavior and testosterone synthesis in aging male mice

Abstract

Twenty-four-month-old male C57BL/6 mice with low serum testosterone levels were used as a late-onset hypogonadism (LOH) animal model for examining the effects of velvet antler polypeptide (VAP) on sexual function and testosterone synthesis. These mice received VAP for 5 consecutive weeks by daily gavage at doses of 100, 200, or 300 mg kg−1 body weight per day (n = 10 mice per dose). Control animals (n = 10) received the same weight-based volume of vehicle. Sexual behavior and testosterone levels in serum and interstitial tissue of testis were measured after the last administration of VAP. Furthermore, to investigate the mechanisms of how VAP affects sexual behavior and testosterone synthesis in vivo, the expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD) in Leydig cells was also measured by immunofluorescence staining and quantitative real-time PCR. As a result, VAP produced a significant improvement in the sexual function of these aging male mice. Serum testosterone level and intratesticular testosterone (ITT) concentration also increased in the VAP-treated groups. The expression of StAR, P450scc, and 3β-HSD was also found to be enhanced in the VAP-treated groups compared with the control group. Our results suggested that VAP was effective in improving sexual function in aging male mice. The effect of velvet antler on sexual function was due to the increased expression of several rate-limiting enzymes of testosterone synthesis (StAR, P450scc, and 3β-HSD) and the following promotion of testosterone synthesis in vivo.

Effects of Bisphenol A on Testosterone Levels and Sexual Behaviors of Male Mice

“…As shown in Figure 1, the mount latency was lengthened at the dose of 100 mg/kg compared with the control (11.64 ± 2.67 min vs. 8.98 ± 1.40 min, P < 0.05). The intromission latency was lengthened at the dose of 50 mg/kg (20.28 ± 3.40 min, P < 0.05) and 100 mg/kg (20.13 ± 2.06 min, P < 0.05).…”

“…As depicted previously, the female mice were used as stimulus females in the test and were resected with double ovaries in advance [8]. One month later, each female mouse was pretreated with estradiol benzoate (50 μg, 48 h before testing, dissolved in 50 μl of peanut oil and injected intraperitoneally) and progesterone (500 μg, 5 h before testing, dissolved in 50 μl of peanut oil and also injected intraperitoneally) reach a state of estrous.…”

“…Immediately after blood sampled, bilateral testes, epididymides, and seminal vesicles were obtained and weighed. Intratesticular testosterone (ITT) concentrations were examined as previously described [8]. In brief, 50 mg testicular tissues from each mouse were homogenized by sonication (2 s × 20 s) in phosphate buffer solution (PBS) and then centrifuged at 10,000 g for ten minutes.…”

“…Sexual behaviors tests have been described previously [8]. The following items were recorded during the tests: mount latency, intromission latency, ejaculation latency, mount frequency, intromission frequency, andcopulatory efficacy (calculated as intromission frequency divided by mount frequency + intromission frequency).…”

Impact of Cellphone Radiation on Sexual Behavior and Serum Concentration of Testosterone and LH in Male Mice

“…As depicted previously, in order to reach a state of estrous, the female mice were resected with double ovaries in advance [8]. One month later, each female mouse was injected intraperitoneally with estradiol benzoate (50 μg, 48 h ahead of testing, dissolved in 50 μl of peanut oil) and progesterone (500 μg, 5 h ahead of testing, dissolved in 50 μl of peanut oil).…”