title: Sensitivity to 6-n-propylthiouracil is associated with gustin (carbonic anhydrase VI) gene polymorphism, salivary zinc, and body mass index in humans.
abstract: BACKGROUND
  The individual ability to taste 6-n-propylthiouracil (PROP) may be correlated with body mass index (BMI) and differences in the salivary proteins involved in taste function, such as the zinc-dependent enzyme gustin, which is a trophic factor of taste buds.
  
  
  OBJECTIVE
  We investigated the possible association of PROP taste responsiveness with gustin gene polymorphism rs2274333 (A/G), salivary ionic zinc concentrations, and BMI.
  
  
  METHODS
  We measured cognitive eating behaviors and BMI in 75 volunteers (28 men and 47 women; mean plusmn SEM age: 25 plusmn 3 y). The intensity of taste perception evoked by PROP and sodium chloride solutions was estimated to evaluate PROP taster status. Salivary ionic zinc concentrations were measured, and molecular analyses of the gustin gene polymorphism were performed in individuals classified by PROP status by using polymerase chain reaction techniques.
  
  
  RESULTS
  We classified subjects as PROP supertasters (n = 27), medium tasters (n = 28), or nontasters (n = 20). Salivary ionic zinc concentrations and BMI were greater in nontasters than in supertasters (P = 0.003 and P = 0.042, respectively). Molecular analyses of gustin DNA showed that allele A and genotype AA were significantly more frequent in supertasters, whereas allele G and genotype GG were significantly more frequent in nontasters (P lt 0.001).
  
  
  CONCLUSIONS
  These data showed that responsiveness to PROP is inversely related to BMI and salivary ionic zinc concentrations. The gustin gene dimorphism rs2274333 observed in supertaster and nontaster subjects may influence the protein conformation and, thereby, affect zinc ion binding. Our data showed a direct association between PROP sensitivity and a polymorphism in the gustin gene that is hypothesized to affect its function. This trial was registered at clinicaltrials.gov as UNICADBSITB-1.
authors.affiliation: Department of Science Applied to Biosystems, University of Cagliari, Monserrato, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Padiglia
authors.forename: Andrea
authors.initials: A
authors.lastname: Zonza
authors.forename: Elena
authors.initials: E
authors.lastname: Atzori
authors.forename: Caterina
authors.initials: C
authors.lastname: Chillotti
authors.forename: Carla
authors.initials: C
authors.lastname: Calò
authors.forename: Beverly J
authors.initials: BJ
authors.lastname: Tepper
authors.forename: Iole Tomassini
authors.initials: IT
authors.lastname: Barbarossa
mesh_terms: D000328:Adult; D000483:Alleles; D015992:Body Mass Index; D002256:Carbonic Anhydrases / Q000235:genetics*; D004247:DNA; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011441:Propylthiouracil; D012463:Saliva / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D013650:Taste Buds / Q000502:physiology; D013652:Taste Threshold / Q000145:classification / Q000235:genetics / Q000502:physiology*; D055815:Young Adult; D015032:Zinc / Q000032:analysis*
chemical_list: D011441:Propylthiouracil; D004247:DNA; D002256:Carbonic Anhydrases; C477051:carbonic anhydrase VI; D015032:Zinc