Low molecular mass proteins are implicated in chemical communication throughout mammalian species, being involved in both perception and delivery of pheromonal compounds. In boars, pheromones are secreted in saliva to cause oestrous sows to take up the mating stance. These pheromones are the 16-androstene steroids, 5a-androsten-3a-ol and 5a-androsten-3-one. The submaxillary glands of boars contain a low molecular mass protein, pheromaxein, which is capable of binding these 16-androstene phero-mones. .
