title: Zinc transporters 1, 2 and 4 are differentially expressed and localized in rats during pregnancy and lactation.
abstract: Zinc metabolism is controlled within relatively restricted limits throughout the life cycle. Expression and localization of zinc transporters 1, 2 and 4 during pregnancy and lactation in small intestine, mammary gland and liver of the rat were investigated using Northern analysis, Western blotting and immunohistochemistry. In maternal tissues, zinc transporter 4 was the most widely expressed among these zinc transporters in the tissues examined. In small intestine and liver, zinc transporter 4 increased from levels found during late gestation, but zinc transporter 1 did not. Zinc transporter 2 expression in small intestine was transient, being highest around parturition, and was not detected in liver. Immunohistochemistry revealed unique patterns of zinc transporter localization at different stages of development. In the placenta, zinc transporters 1 and 4 were found concentrated along the villous visceral splanchnopleure. In the mammary gland, zinc transporter 4 was most abundant in cells surrounding the alveolar ducts and oriented to the basement lamina. All three transporters were highly expressed in neonatal small intestine, principally near the apical surface, but zinc transporters 1 and 4 increased in abundance at the basolateral surface during development. Zinc transporter 2 was oriented apically, directly adjacent to the microvilli of enterocytes. Within the intestine, expression of each transporter was limited to enterocytes. These results support a role for these transporters in maintaining an adequate zinc supply derived from the maternal diet for zinc acquisition and use by the fetus and neonate.
authors.affiliation: Food Science and Human Nutrition Department, University of Florida, Gainesville, FL, USA.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Liuzzi
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Bobo
authors.forename: Li
authors.initials: L
authors.lastname: Cui
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McMahon
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cousins
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001940:Breast / Q000378:metabolism* / Q000648:ultrastructure; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D005314:Embryonic and Fetal Development; D005260:Female; D007421:Intestine, Small / Q000378:metabolism* / Q000648:ultrastructure; D007774:Lactation / Q000378:metabolism*; D008099:Liver / Q000378:metabolism* / Q000648:ultrastructure; D010920:Placenta / Q000378:metabolism* / Q000648:ultrastructure; D011247:Pregnancy; D051381:Rats; D015032:Zinc / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C017800:zinc-binding protein; D015032:Zinc