Bozena Jemiolo

Chemistry of male dominance in the house mouse,Mus domesticus

Two terpenic constituents, E,E,-α-farnesene and E-β-farnesene, were found to be elevated in dominant male urine when compared to subordinate or control males. These two urinary compounds were absent in the bladder urine of males; however, they were the most prominent constituents of the preputial glands aliquots. The results of a two-choice preference test, conducted on ICR/Alb subordinate males, gave a strong indication that these two terpenic constituents introduced into the previously attractive stimulus significantly discouraged prolonged investigations by male mice. The compounds, whether present in the urine matrix or water, rendered the stimulus with a quality behaviorally similar to the urine of dominant males. It appears that they may be synonymous with the previously described aversion signal produced by dominant males. We suggest that these compounds may play a wide-ranging role in the territorial marking behavior of male mice.

Behavioural and endocrine responses of female mice to synthetic analogues of volatile compounds in male urine

Abstract The urine of intact, adult male mice elicits more investigatory sniffing from female mice than does the urine of castrated males. When either of two androgen-dependent urinary compounds, 2- sec -butyl dihydrothiazole or dehydro- exo -brevicomin are added to castrate urine, its relative attractiveness remains the same. When both compounds are added to castrate urine, however, its activity is enhanced and the castrate urine becomes as attractive to females as whole, intact male urine. Females exposed to the reconstituted ‘normal’ urine for 3 min per day, displayed more frequent oestrus cycles. The two synthetic compounds are synergistic in the context of castrate urine, producing an olfactory message that behaviourally and physiologically mimics the activity of the normal biological signal.

A unique urinary constituent, 6-hydroxy-6-methyl-3-heptanone, is a pheromone that accelerates puberty in female mice.

BACKGROUND Olfactorily mediated puberty acceleration in female mice (measured by an increase in uterine weight) has been observed since the 1960s without the active chemosignal being structurally identified. There are many controversies in the literature as to whether this male-originated pheromone is a volatile substance. We investigated the chemical nature of the urinary fractions that are responsible for the characteristic uterine weight increases. RESULTS The active pheromone was identified as 5,5-dimethyl-2-ethyltetrahydrofuran-2-ol and/or its open-chain tautomer (6-hydroxy-6-methyl-3-heptanone). A series of cyclic vinyl ethers were isolated from chromatographically active fractions of the urine. Because these compounds did not accelerate puberty, we postulated that these ethers were degradation products of a lactol (5,5-dimethyl-2-ethyltetrahydrofuran-2-ol). The lactol was then detected directly in the mouse urine extract using a silylation agent. Synthetic 6-hydroxy-6-methyl-3-heptanone had strong biological activity, whereas its close structural analogs did not. CONCLUSIONS The male house mouse excretes into its urine a large quantity of a volatile substance that has a unique lactol/hydroxyketone structure. This substance is capable of binding to the less volatile urinary constituents, such as proteins or peptides, and is active in puberty-acceleration bioassays. The controversies regarding the volatility of the puberty-accelerating pheromones can now be explained by considering a complex of volatile lactol/hydroxyketone and urinary proteins.

Pattern of volatile compounds in dominant and subordinate male mouse urine

The urinary volatiles from dominant and subordinate male mice were chromatographically compared, both immediately and seven days after dominant-subordinate relationships between pairs were formed. Statistical comparison of the peak areas of volatile constituents present in male urine revealed that 16 urinary compounds exhibited substantial concentration differences depending upon social status of the animals. Urinary dihydrofurans, ketones, and acetates exhibited a significant, long-term (seven-day) decrease in the urine of subordinates when compared to control and dominant males. Two sesquiterpenic compounds, α- and β-farnesene, were elevated only in the dominant urine one week after dominance was established. 2-(sec-Butyl)-4,5-dihydrothiazole was found in higher concentration in bladder or excreted urine of dominant males when compared to subordinates. Of the 16 compounds subjected to statistical analysis, four exhibited hormonal dependency: α- and β-farnesene, dehydro-exo-brevicomin, and 2-(sec-butyl)-4,5-dihydrothiazole. Neither dehydro-exo-brevicomin nor 2-(sec-butyl)-4,5-dihydrothiazole was present in the urine of immature and castrated males. Testosterone treatment restores their presence in male urine. Also, α- and β-farnesene were absent in the urine of immature males and significantly reduced in the urine of castrated males. The absence of α- and β-farnesene in bladder urine suggests that one of the sex-accessory glands may be the site of their origin.

Puberty-affecting synthetic analogs of urinary chemosignals in the house mouse, Mus domesticus

Endocrinologically- and socially-dependent volatile constituents of female mouse urine, identified in a previous study, were tested for their capability to accelerate puberty and extend the estrous period in young females. Several volatile ketones advanced puberty by approximately three days and extended the period of vaginal cornification in 55-75% of exposed females. High High concentrations of these substances were capable of overriding the known puberty-delaying chemosignals. Volatile cyclic enol ethers were also effective in extending estrus, but not puberty acceleration.

Dynamics of excretion of urinary chemosignals in the house mouse (Mus musclus) during the natural estrous cycle

The volatile fraction of urinary metabolites was investigated chromatographically at five different stages of the natural estrous cycle. A very substantial endocrine dependency has been noted for 11 compounds: 4 ketones, 2 acetate esters, 3 dihydrofuran isomers, dehydro-exo-brevicomin, and 2,5-dimethylpyrazine. The compounds were structurally verified through combined gas chromatography/mass spectrometry.

Putative Chemical Signals from White-Tailed Deer (Odocoileus virginianus): Social and Seasonal Effects on Urinary Volatile Excretion in Males

Urine samples collected from dominant and subordinate male white-tailed deer during the breeding and nonbreeding season were analyzed by combined gas chromatography–mass spectrometry (GC-MS). Fifty-five volatiles were found in measurable quantities. Ketones were most numerous, followed by alcohols and alkanes. Nine compounds were common to both dominants and subordinates during the breeding season. Of these nine, three were present in higher concentrations in dominants, and six were higher in subordinates. During the breeding season, nine compounds were found exclusively in the urine of dominants, whereas 19 compounds were found exclusively in the urine of subordinates. Concentrations of several compounds were dependent on the time of year (breeding vs. nonbreeding season). Differences in compound presence and concentration may produce a rank-specific odor, although we suggest that differing concentrations of these suites of compounds may be more important for the identification of social status than the presence of individual compounds. Since mature male white-tailed deer urinate on their tarsal glands frequently during the breeding season, this behavior may allow a deer to simultaneously scent-mark its environment and carry intraspecific cues indicative of social status.

Variations in mouse (Mus musculus) urinary volatiles during different periods of pregnancy and lactation

Mouse urine samples from different pregnancy and lactation periods were examined by capillary gas chromatography to assess variations in the volatile signals that may affect the endocrine function of other females. Statistically significant changes in the excretion of certain urinary volatiles were observed; from 26 readily quantifiable constituents, 14 appear to be under the endocrine control. These selected components, positively identified through mass spectrometry and retention data, and the synthetic standards are ketones, unsaturated alcohols, esters, and cyclic vinyl ethers.

Urinary volatile profiles of pine vole,Microtus pinetorum, and their endocrine dependency

The volatile compounds identified by combined gas chromatography-mass spectrometry inMicrotus pinetorum urine include alcohols, aldehydes, hydrocarbons, ketones, nitriles, and pyrazines. Several lactone derivatives were found to be characteristic urinary substances of this species. Ovariectomy depressed concentrations of only five out of a great number of profile constituents. Elevating estrogen levels (by exposing females to male-soiled bedding or treating them with estradiol) tends to depress the urinary concentration of a number of selected volatiles. Estrogen implantation provoked a periodic increase in the level of three compounds (nonanal, benzal-dehyde, and an unidentified substance). The volatile profile of castrate male urine was similar to that of intact male urine. Female urine contained γ-octanoic lactone and two pyrazine derivatives in higher concentrations andp-methyI-propenylbenzene in a lower concentration, when compared to male urine. No qualitative differences between the urinary profiles of males and females were observed.

Stereoselectivity in mammalian chemical communication: Male mouse pheromones

Two male mouse pheromones, 3,4-dehydro-exo-brevicomin (DHB) and 2-sec-butyldihydrothiazole (SBT), are chiral molecules which were previously tested in their respective bioasays as racemic mixtures. The focus of this study has been to determine the absolute configuration of their natural forms and its relation to stereospecific biological action. DHB was established as the R,R-enantiomer possessing biological activity. Due to an extremely easy racemization of SBT under very mild conditions, enantioselectivity of its transmission and its action at the receptor site appear to be of secondary importance.