Pheromones of hamster vaginal discharge Attraction to femtogram amounts of dimethyl disulfide and to mixtures of volatile components

Abstract

The responses of normal male hamsters to the odors of several components of estrous female hamster vaginal discharge (FHVD) were quantified with a two-bottle preference test in order to clarify the role of dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) in the attraction of males to females. These two compounds were originally isolated and identified in two separate, behaviorally active fractions of FHVD, one containing DMDS and the second containing DMTS. However, only authentic DMDS proved to be attractive to males; DMTS was inactive in the amounts tested (50 ng to 10 μg). When smaller amounts of highly purified samples of DMTS (0.03–3.32 ng) are assayed, measurable amounts of activity are obtained. This activity of authentic DMTS is not due to any intrinsic activity of its own but rather can be ascribed to the activity of the residual DMDS (0.07%) that it contains. Highly purified samples of authentic DMDS (containing 0.03% DMTS) were again found to be attractive to males. Doses as small as 500 fg were significantly active when compared to controls. Arguments are presented suggesting that the behaviorally effective dose of DMDS is several orders of magnitude less than 500 fg. Deliberate mixtures of DMDS and DMTS failed to show any synergistic effects. In fact, at the two lowest doses examined (0.1 and 0.46 ng total sulfides), the response obtained with the mixture was smaller than that expected if DMDS were the only odorant in the solution. Therefore, DMTS seems to suppress the activity of DMDS.