title: Prolactin and the dietary protein/carbohydrate ratio regulate the expression of SNAT2 amino acid transporter in the mammary gland during lactation.
abstract: The sodium coupled neutral amino acid transporter 2 (SNAT2/SAT2/ATA2) is expressed in the mammary gland (MG) and plays an important role in the uptake of alanine and glutamine which are the most abundant amino acids transported into this tissue during lactation. Thus, the aim of this study was to assess the amount and localization of SNAT2 before delivery and during lactation in rat MG, and to evaluate whether prolactin and the dietary protein/carbohydrate ratio might influence SNAT2 expression in the MG, liver and adipose tissue during lactation. Our results showed that SNAT2 protein abundance in the MG increased during lactation and this increase was maintained along this period, while 24 h after weaning it tended to decrease. To study the effect of prolactin on SNAT2 expression, we incubated MG explants or T47D cells transfected with the SNAT2 promoter with prolactin, and we observed in both studies an increase in the SNAT2 expression or promoter activity. Consumption of a high-protein/low carbohydrate diet increased prolactin concentration, with a concomitant increase in SNAT2 expression not only in the MG during lactation, but also in the liver and adipose tissue. There was a correlation between SNAT2 expression and serum prolactin levels depending on the amount of dietary protein/carbohydrate ratio consumed. These findings suggest that prolactin actively supports lactation providing amino acids to the gland through SNAT2 for the synthesis of milk proteins.
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Velázquez-Villegas
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Adriana M
authors.initials: AM
authors.lastname: López-Barradas
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Nimbe
authors.initials: N
authors.lastname: Torres
authors.affiliation: Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Rogelio
authors.initials: R
authors.lastname: Hernández-Pando
authors.affiliation: Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: León-Contreras
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Omar
authors.initials: O
authors.lastname: Granados
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico.
authors.forename: Victor
authors.initials: V
authors.lastname: Ortíz
authors.affiliation: Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México D.F. 14000, Mexico. Electronic address: tovar.ar@gmail.com.
authors.forename: Armando R
authors.initials: AR
authors.lastname: Tovar
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D026924:Amino Acid Transport System A / Q000235:genetics / Q000378:metabolism*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D007774:Lactation / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000378:metabolism*; D039382:Maternal Nutritional Physiological Phenomena; D008894:Milk Proteins / Q000096:biosynthesis; D009752:Nutritional Status; D011247:Pregnancy; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D046509:Tissue Culture Techniques; D014162:Transfection; D014886:Weaning
chemical_list: D026924:Amino Acid Transport System A; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D008894:Milk Proteins; D012333:RNA, Messenger; C498798:Slc38a2 protein, mouse; D011388:Prolactin
keywords: Amino acid transport; Dietary protein/carbohydrate ratio; Lactation; Mammary gland; Prolactin; SNAT2