Androstadienone odor thresholds in adolescents Thomas Hummel a, * , Franziska Krone a,b , Johan N. Lundstro ¨m c , Oliver Bartsch b a Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstr. 74, 01307 Dresden, Germany b Department of Clinical Genetics, University of Dresden Medical School, Fetscherstr. 74, 01307 Dresden, Germany c Department of Psychology, Uppsala University, Box 1225, SE-751 42 Uppsala, Sweden Received 24 March 2004; revised 12 August 2004; accepted 29 October 2004 Available online 16 January 2005 Abstract A sex-related difference in olfactory sensitivity to androstenone has been reported to occur during adolescence. More males than females exhibited anosmia to androstenone, or an increase in androstenone threshold with age. The current study addressed the question whether similar, sexually dimorphic effects of aging over puberty can also be found for androstadienone. A total of 102 subjects participated (36 females, 66 males). Similar to previous investigations, subjects were divided into a group of 47 individuals with a mean age of 13.3 years, defined as pre/peri-pubertal, and a group of 55 subjects with a mean age of 17.1 years, defined as post-pubertal. All subjects underwent tests for verbal abilities, general olfactory function, and measurements of androstadienone thresholds. The study provided the following major results: (1) Male subjects exhibited higher androstadienone sensitivity in the pre/peri-pubertal group as compared to the post-pubertal group. This difference was not observed in female subjects. Correspondingly, a negative correlation between age and androstadienone sensitivity was found for male subjects, but not for female subjects. (2) In contrast to this sex-specific change of the androstadienone odor threshold, verbal skills and odor identification abilities increased with age in all subjects regardless of their sex. In conclusion, the present observations confirm previous research on sex-differentiated effects of aging during puberty on sensitivity towards odorous steroids. While the underlying causes are unknown, it may be hypothesized that the decreased sensitivity could result from the increased endogenous levels of androstadienone in male subjects. Future studies should include both steroid and non-steroid odorants to futher explore these age-related changes. D 2004 Elsevier Inc. All rights reserved. Keywords: Hormone; Olfaction; Smell; Nose; Puberty Introduction Chemical signals, often called bpheromonesQ (Beau- champ et al., 1976; Karlson and Lu ¨scher, 1959), are determinants of the communication between individuals within species. Pheromonal communication has been demonstrated in most phyla (McClintock et al., 2001) and several examples of mammalian pheromonal responses exist. Examples range from pheromonal alteration of the endocrine system such as suppression or induction of estrus, acceleration of puberty, or blocking of pregnancy (Preti and Wysocki, 1999), to more complex behavior such as mating (Reed et al., 1974). Androstadienone (4, 16-androstadien-3-one) is a member of the family of odorous steroids. In human males, this substance has been found at blood concentrations of 98 ng/ 100 ml (Brooksbank et al., 1969) and in the axillary secretion with a mean value of 228 pmol/total axillary hair weight (Nixon et al., 1988). Androstadienone can also be found in women, but in a much smaller concentration (Brooksbank et al., 1969). Androstadienone is known to have unique psychophysical characteristics. The sensitivity distribution in the population is bimodal, including a subset of highly sensitive individuals (Lundstrom et al., 2003b). This bimodality can also be seen for the closely structurally related steroid androstenone (5 alpha-androst-16en-3one) (Amoore, 1991). A large portion of the research on odorous components with gonadal origin has been done on androstenone. 0018-506X/$ - see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.yhbeh.2004.10.007 * Correspondence author. Fax +49 351 458 4326. E-mail address: thummel@rcs.urz.tu-dresden.de (T. Hummel). Hormones and Behavior 47 (2005) 306 – 310 www.elsevier.com/locate/yhbeh