3-Ethyl-2,7-dimethyl octane, a testosterone dependent unique urinary sex pheromone in male mouse (Mus musculus)

A previous investigation revealed that urine from normal male mice contained five unique volatile constituents; namely: 3-cyclohexene-1-methanol (I); 3-amino triazole (II); 4-ethyl phenol (III); 3-ethyl-2,7-dimethyl octane (IV); 1-iodoundecane (V). The present study was designed to find out whether the production of these male specific urinary compounds was androgen-dependent. Urine of castrated and castrated plus testosterone-treated male mice was analyzed using gas chromatography linked mass spectrometry (GC–MS). Even though castrated male urine contained 10 detectable compounds, the five male specific compounds present in intact males were absent in castrated male mice urine. Only 3-ethyl-2,7-dimethyl octane (IV) reappeared following testosterone treatment into castrated males. Our earlier bioassay revealed that this compound was involved in attracting females. The present study concluded that this compound was a male specific volatile cue that acted as a releaser pheromone and its production was under the control of androgen.