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Sex- and gonad-affecting scent compounds and 3 male pheromones in the rat.

Zhang JX, Sun L, Zhang JH, Feng ZY - Chem. Senses (2008)

Bottom Line: Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females.However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness.Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, China. zhangjx@ioz.ac.cn

ABSTRACT
This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography-mass spectrometry (GC-MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.

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Duration of investigation (mean ± standard error, s) of female rats on castrate urine (CU) versus CU added with squalene (S) during a 3-min choice test (*, P < 0.05, paired t-test or Wilcoxon matched-pairs signed-rank test).
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fig7: Duration of investigation (mean ± standard error, s) of female rats on castrate urine (CU) versus CU added with squalene (S) during a 3-min choice test (*, P < 0.05, paired t-test or Wilcoxon matched-pairs signed-rank test).

Mentions: Binary choice test revealed that female rats, which exhibited an estrous cycle of about 4 days without synchrony, showed a significant preference for male urine over female urine during 4 consecutive days (Day 1: t9 = 2.791, P = 0.021; Day 2: t9 = 3.151, P = 0.012; Day 3: t9 = 2.283, P = 0.048; Day 4: t9 = 2.657, P = 0.026) (Figure 3). These responsive females, regardless of their stages of estrous cycles, were used to test for their preferences for castrated male urine (CMU) added with putative pheromone analogs over blank CMU (see below). As a result, females showed a significant preference for intact male urine over CMU (t9 = 3.157, P = 0.012) (Figure 4). Replenishing CMU with 2-heptanone at 800 ppm (Z = 2.395, n = 10, P = 0.017) or 1% 2-heptanone (t9 = 2.359, P = 0.040) significantly increased the attractiveness of CMU to females, but the preference was not shown when 10–400 ppm of either of the compounds was added (Figure 5). Likewise, females showed a higher level of preference for CMU added with 4-ethyl phenol at 200 ppm (t9 = 2.537, P = 0.032) but did not show a significant preference between blank CMU and CMU added with 40, 100, 400, 800 ppm, or 1% of the compound (Figure 6). Female also showed a heightened level of preference to CMU added with squalene at 50 ppm (Z = 2.293, n = 10, P = 0.022), 200 ppm (t8 = 2.073, P = 0.038), 400 ppm (t9 = 3.228, degrees of freedom = 9, P = 0.010), or 1% (Z = 2.803, n = 10, P = 0.005), compared with the control (blank CMU). However, females showed no preference between blank CMU and CMU added with squalene at 1–20 ppm (Figure 7). Furthermore, adding a mixture of squalene (1 ppm), 2-heptanone (10 ppm), and 4-ethyl phenol (40 ppm) at the levels approximate to those present in male urine enhanced the preferential response of females (t9 = 3.303, P = 0.009) (Figure 8). However, such a scented CMU was still less attractive to females than was intact male urine (t9 = 5.918, P = 0.000) (Figure 8).


Sex- and gonad-affecting scent compounds and 3 male pheromones in the rat.

Zhang JX, Sun L, Zhang JH, Feng ZY - Chem. Senses (2008)

Duration of investigation (mean ± standard error, s) of female rats on castrate urine (CU) versus CU added with squalene (S) during a 3-min choice test (*, P < 0.05, paired t-test or Wilcoxon matched-pairs signed-rank test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2533420&req=5

fig7: Duration of investigation (mean ± standard error, s) of female rats on castrate urine (CU) versus CU added with squalene (S) during a 3-min choice test (*, P < 0.05, paired t-test or Wilcoxon matched-pairs signed-rank test).
Mentions: Binary choice test revealed that female rats, which exhibited an estrous cycle of about 4 days without synchrony, showed a significant preference for male urine over female urine during 4 consecutive days (Day 1: t9 = 2.791, P = 0.021; Day 2: t9 = 3.151, P = 0.012; Day 3: t9 = 2.283, P = 0.048; Day 4: t9 = 2.657, P = 0.026) (Figure 3). These responsive females, regardless of their stages of estrous cycles, were used to test for their preferences for castrated male urine (CMU) added with putative pheromone analogs over blank CMU (see below). As a result, females showed a significant preference for intact male urine over CMU (t9 = 3.157, P = 0.012) (Figure 4). Replenishing CMU with 2-heptanone at 800 ppm (Z = 2.395, n = 10, P = 0.017) or 1% 2-heptanone (t9 = 2.359, P = 0.040) significantly increased the attractiveness of CMU to females, but the preference was not shown when 10–400 ppm of either of the compounds was added (Figure 5). Likewise, females showed a higher level of preference for CMU added with 4-ethyl phenol at 200 ppm (t9 = 2.537, P = 0.032) but did not show a significant preference between blank CMU and CMU added with 40, 100, 400, 800 ppm, or 1% of the compound (Figure 6). Female also showed a heightened level of preference to CMU added with squalene at 50 ppm (Z = 2.293, n = 10, P = 0.022), 200 ppm (t8 = 2.073, P = 0.038), 400 ppm (t9 = 3.228, degrees of freedom = 9, P = 0.010), or 1% (Z = 2.803, n = 10, P = 0.005), compared with the control (blank CMU). However, females showed no preference between blank CMU and CMU added with squalene at 1–20 ppm (Figure 7). Furthermore, adding a mixture of squalene (1 ppm), 2-heptanone (10 ppm), and 4-ethyl phenol (40 ppm) at the levels approximate to those present in male urine enhanced the preferential response of females (t9 = 3.303, P = 0.009) (Figure 8). However, such a scented CMU was still less attractive to females than was intact male urine (t9 = 5.918, P = 0.000) (Figure 8).

Bottom Line: Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females.However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness.Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, China. zhangjx@ioz.ac.cn

ABSTRACT
This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography-mass spectrometry (GC-MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-beta-farnesene and E-alpha-farnesene, both richer in females than males, might be putative female pheromones.

Show MeSH