Dehnhard M, Heistermann M, Göritz F, Hermes R, Hildebrandt T, Haber H
Institute for Zoo Biology and Wildlife Research, PF 601103, D-10252 Berlin, Germany.
Reproduction. 2001 Mar;121(3):475-84. doi: 10.1530/rep.0.1210475.
Air-borne volatile substances have been demonstrated to signal oestrus, induce ovulation and synchronize ovarian activity in different mammals. An oestrous-related pheromone of the female Asian elephant (Elephas maximus) is known to induce behavioural responses in elephant bulls. Additional data revealed that timing of oestrus in females with close social relationships tends to be synchronized. Therefore, urine from female Asian elephants might be expected to contain luteal phase-dependent volatile substances, which may function as additional chemical signals in this species. The aim of the present study was to identify such compounds and to investigate their pattern of excretion throughout the ovarian cycle. Urine samples were collected three times a week during the follicular phase and one to three times a week during the luteal phase from five adult female Asian elephants from a total of 13 non-conception cycles and one conception cycle, including the first 72 weeks of pregnancy. A simple headspace solid-phase microextraction method has been developed for quantification of urinary volatile substances and analysis was performed by gas chromatography. The comparison of urine collected during the follicular and the luteal phase indicated the presence of two luteal phase-dependent substances. Mass spectrometry was used to identify one substance as 5alpha-androst-2-en-17-one and a second substance as the corresponding alcoholic compound 5alpha-androst-2-en-17beta-ol. The 5alpha-androst-2-en-17beta-ol and -17-one profiles reflected cyclic ovarian activity with clear (10-20-fold) luteal phase increases. Furthermore, measurements of both compounds were correlated positively with the concentration of urinary pregnanetriol and indicated cycle duration (15.1 +/- 1.2 weeks) similar to that obtained from pregnanetriol measurements (15.2 +/- 1.6 weeks). The results demonstrate the presence of two luteal phase-specific steroidal volatile compounds in elephant urine. One of the substances, 5alpha-androst-2-en-17-one, has been demonstrated in human axillary bacterial isolates. The measurement of both volatile substances in elephant urine can be used for rapid detection of the stage of the ovarian cycle, as the analysis can be completed within 2 h.
空气传播的挥发性物质已被证明能在不同哺乳动物中传递发情信号、诱导排卵并使卵巢活动同步。已知亚洲象(Elephas maximus)雌性的一种与发情相关的信息素能在雄象中引发行为反应。更多数据显示,社会关系密切的雌性大象发情时间趋于同步。因此,可以预期亚洲象雌性尿液中含有与黄体期相关的挥发性物质,这些物质可能在该物种中作为额外的化学信号发挥作用。本研究的目的是鉴定这些化合物,并研究它们在整个卵巢周期中的排泄模式。在卵泡期,每周从5头成年亚洲象收集3次尿液样本,在黄体期每周收集1至3次尿液样本,共收集了13个非受孕周期和1个受孕周期(包括怀孕的前72周)的尿液样本。已开发出一种简单的顶空固相微萃取方法用于定量尿液中的挥发性物质,并通过气相色谱进行分析。卵泡期和黄体期收集的尿液比较表明存在两种与黄体期相关的物质。利用质谱法将一种物质鉴定为5α-雄甾-2-烯-17-酮,另一种物质鉴定为相应的醇类化合物5α-雄甾-2-烯-17β-醇。5α-雄甾-2-烯-17β-醇和-17-酮的含量变化反映了卵巢的周期性活动,黄体期含量明显升高(10至20倍)。此外,两种化合物的测量值与尿孕三醇浓度呈正相关,且表明的周期时长(15.1±1.2周)与从孕三醇测量值得到的结果(15.2±1.6周)相似。结果表明大象尿液中存在两种黄体期特异性甾体挥发性化合物。其中一种物质5α-雄甾-2-烯-17-酮已在人类腋窝细菌分离物中得到证实。测量大象尿液中的这两种挥发性物质可用于快速检测卵巢周期阶段,因为分析可在2小时内完成。