1-Iodo-2methylundecane, a putative estrus-specific urinary chemo-signal of female mouse (Mus musculus)

The present study was designed to identify the urinary volatiles across various reproductive stages of female mice in order to detect estrus-specific chemical signal. The urine of adult female mice were extracted with dichloromethane (1:1 ratio, v/v) and analyzed by gas chromatography linked mass-spectrometry (GC-MS). Numerous compounds were identified during estrus cycle of female mice urine. Among these, the compounds, namely, isocroctylhydrazine, 4-methyl-2-heptanone and auzulene were specific to proestrus stage and the compounds, 1-H-cyclopop-e.auzulene, caryophyllene, copanene were specific to estrus stage. However, the compound, 1-iodo-2methyl undecane (1I2MU) was observed both in proestrus and estrus phases and was absent in all other phases. The volatile signal produced at the end of proestrus and the beginning of estrus phase appears to be behaviourally important in the attraction of males. Moreover, the behaviour assay revealed that the compound, 1I2MU, is involved in attracting the male mice. This result concludes that the 1-iodo-2methyl undecane is considered as a putative estrus-specific chemo-signal.