title: Participation of mammary gland in long-chain polyunsaturated fatty acid synthesis during pregnancy and lactation in rats.
abstract: Metabolic adaptations are triggered in the maternal organism to synthesize milk with an adequate concentration of long-chain polyunsaturated fatty acids (LC-PUFAs) required to the newborn. They may be a high uptake of dietary linoleic acid and its conversion to LC-PUFAs by desaturases of fatty acids (FADS) 1 and 2 in the mammary gland (MG). It is unknown if they also occur from onset of pregnancy. The aim of this study was to explore the participation of the MG as a mechanism involved in LC-PUFAs synthesis to support their demand during pregnancy and lactation in rats. The expression of desaturases in MG was significantly (P<0.05) higher (12.3-fold for FADS1 and 41.2-fold for FADS2) during the late pregnancy and throughout lactation (31.7-fold for FADS1 and 67.1-fold higher for FADS2) than in nonpregnant rats. SREBF-1c showed a similar pattern of increase during pregnancy but remained higher only during the early lactation (11.7-fold, P<0.005). Transcript of ELOVL6 and FASN increased throughout pregnancy and lactation, respectively. ELOVL5 mRNA increased in MG only during lactation (2.8 to 5.3-fold, P<0.005). Accordingly, a higher content of LC-PUFAs was found in lactating MG than in nonpregnant rats. Results suggest that MG participates from late pregnancy and throughout lactation by expressing desaturases and elongases as a mechanism involved in LC-PUFAs synthesis, probably by SREBF-1c. Because desaturases and ELOVL5 were expressed in cultured lactocytes and such expression was downregulated by linoleic and arachidonic acid, these cells may be a useful model for understanding the regulatory mechanisms for LC-PUFAs synthesis in MG.
authors.affiliation: Laboratorio de Biología Molecular, Unidad de Investigación Médica en Nutrición, Hospital de Pediatría, Centro Medico Nacional Siglo XXI, IMSS, Mexico City, Mexico. maricela.rodriguez.cruz@gmail.com
authors.forename: Maricela
authors.initials: M
authors.lastname: Rodriguez-Cruz
authors.forename: Raúl
authors.initials: R
authors.lastname: Sánchez
authors.forename: Apolos M
authors.initials: AM
authors.lastname: Sánchez
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Kelleher
authors.forename: Fausto
authors.initials: F
authors.lastname: Sánchez-Muñoz
authors.forename: Jorge
authors.initials: J
authors.lastname: Maldonado
authors.forename: Mardia
authors.initials: M
authors.lastname: López-Alarcón
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D000081031:Fatty Acid Elongases; D064429:Fatty Acid Synthases / Q000235:genetics / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D005260:Female; D007774:Lactation / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism*
chemical_list: D005231:Fatty Acids, Unsaturated; D012333:RNA, Messenger; C497389:Srebf1 protein, rat; D051780:Sterol Regulatory Element Binding Protein 1; D044943:Fatty Acid Desaturases; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases; D064429:Fatty Acid Synthases