title: No up-regulation of the phosphatidylethanolamine N-methyltransferase pathway and choline production by sex hormones in cats.
abstract: BACKGROUND
  Feline hepatic lipidosis (FHL) is a common cholestatic disease affecting cats of any breed, age and sex. Both choline deficiency and low hepatic phosphatidylethanolamine N-methyltransferase (PEMT) activity are associated with hepatic lipidosis (HL) in humans, mice and rats. The PEMT expression is known to be upregulated by oestrogens, protecting the females in these species from the development of HL when exposed to choline deficient diets. The aim of the present study was to evaluate the influence of sex hormones on choline synthesis via the PEMT pathway in healthy male and female cats before and after spaying/neutering, when fed a diet with recommended dietary choline content.
  
  
  RESULTS
  From six female and six male cats PEMT activity was assayed directly in liver biopsies taken before and after spaying/neutering, and assessed indirectly by analyses of PEMT-specific hepatic phosphatidylcholine (PC) species and plasma choline levels. Hepatic PEMT activity did not differ between intact female and male cats and no changes upon spaying/neutering were observed. Likewise, no significant differences in liver PC content and PEMT-specific polyunsaturated PC species were found between the sexes and before or after spaying/neutering.
  
  
  CONCLUSIONS
  These results suggest that choline synthesis in cats differs from what is observed in humans, mice and rats. The lack of evident influence of sex hormones on the PEMT pathway makes it unlikely that spaying/neutering predisposes cats for HL by causing PC deficiency as suggested in other species.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, The Netherlands. c.valtolina@uu.nl.
authors.forename: Chiara
authors.initials: C
authors.lastname: Valtolina
authors.affiliation: Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, Yalelaan 2, 3584 CM, Utrecht, The Netherlands. a.b.vaandrager@uu.nl.
authors.forename: Arie B
authors.initials: AB
authors.lastname: Vaandrager
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, The Netherlands. r.p.favier@uu.nl.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Favier
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, The Netherlands. j.h.robben@uu.nl.
authors.forename: Joris H
authors.initials: JH
authors.lastname: Robben
authors.affiliation: Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine and Institute of Biomembranes, Utrecht University, Yalelaan 2, 3584 CM, Utrecht, The Netherlands. t.maidina@uu.nl.
authors.forename: Maidina
authors.initials: M
authors.lastname: Tuohetahuntila
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, The Netherlands. a.kummeling@uu.nl.
authors.forename: Anne
authors.initials: A
authors.lastname: Kummeling
authors.affiliation: Research and Development, Affinity Petcare, Pl. Xavier Cugat, 2 Edificio D, 3ª, Planta, 08174 St. Cugat del Vallès, Barcelona, Spain. ijeusette@affinity-petcare.com.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jeusette
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM, Utrecht, The Netherlands. j.rothuizen@uu.nl.
authors.forename: Jan
authors.initials: J
authors.lastname: Rothuizen
mesh_terms: D000818:Animals; D002415:Cats; D002794:Choline / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D007044:Hysterectomy / Q000662:veterinary*; D008099:Liver / Q000201:enzymology; D008297:Male; D009919:Orchiectomy / Q000662:veterinary*; D010052:Ovariectomy / Q000662:veterinary*; D050918:Phosphatidylethanolamine N-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D050918:Phosphatidylethanolamine N-Methyltransferase; D002794:Choline