title: Expression of adenosine 5'-monophosphate-Activated protein kinase (AMPK) in ovine testis (Ovis aries): In vivo regulation by nutritional state.
abstract: In the present study, we identified AMPK and investigated its potential role in steroidogenesis in vivo in the ovine testis in response to variation in nutritional status (fed control vs. restricted). We performed immunoblotting to show that both active and non-active forms of AMPK exist in ovine testis and liver. In testis, we confirmed these results by immunohistochemistry. We found a correlation between ATP (Adenosine-Triphosphate) levels and the expression of AMPK in liver. Also, low and high caloric diets induce isoform-dependent AMPK expression, with an increase in α2, ß1ß2 and γ1 activity levels. Although the restricted group exhibited an increase in lipid balance, only the triglyceride and HC-VLDL (Cholesterol-Very low density lipoprotein) fractions showed significant differences between groups, suggesting an adaptive mechanism. Moreover, the relatively low rate of non-esterified fatty acid released into the circulation implies re-esterification to compensate for the physiological need. In the fed control group, AMPK activates the production of testosterone in Leydig cells; this is, in turn, associated with an increase in the expression of 3ß-HSD (3 beta hydroxy steroid deshydrogenase), p450scc (Cholesterol side-chain cleavage enzyme) and StAR (Steroidogenic acute regulatory protein) proteins induced by decreased MAPK ERK½ (Extracellular signal-regulated kinase -Mitogen-activated protein kinase) phosphorylation. In contrast, in the restricted group, testosterone secretion was reduced but intracellular cholesterol concentration was not. Furthermore, the combination of high levels of lipoproteins and emergence of the p38 MAP kinase pathway suggest the involvement of pro-inflammatory cytokines, as confirmed by transcriptional repression of the StAR protein. Taken together, these results suggest that AMPK expression is tissue dependent.
authors.affiliation: Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté des Sciences Biologiques (FSB), Laboratoire de Recherche sur les Zones Arides, (LRZA), BP 32 El Alia 16111, Bab Ezzouar 16111, Algérie; Centre de Recherche Scientifique et Technique en Analyses Physico-chimiques (C.R.A.P.C), BP 384, Zone industrielle de Bou-Ismail, RP 42004 w., Tipaza, Algérie. Electronic address: nadbio71.doc@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Taibi
authors.affiliation: Unité de Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, 37380 Nouzilly, France. Electronic address: Jdupont@tours.inra.fr.
authors.forename: J
authors.initials: J
authors.lastname: Dupont
authors.affiliation: Nutristar International Group CCPA. Electronic address: Zahir.bouguermouh@nutristar.fr.
authors.forename: Z
authors.initials: Z
authors.lastname: Bouguermouh
authors.affiliation: Unité de Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, 37380 Nouzilly, France. Electronic address: Pascal.froment@tours.inra.fr.
authors.forename: P
authors.initials: P
authors.lastname: Froment
authors.affiliation: Unité de Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, 37380 Nouzilly, France. Electronic address: Christelle.rame@tours.inra.fr.
authors.forename: C
authors.initials: C
authors.lastname: Ramé
authors.affiliation: Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté des Sciences Biologiques (FSB), Laboratoire de Recherche sur les Zones Arides, (LRZA), BP 32 El Alia 16111, Bab Ezzouar 16111, Algérie. Electronic address: anane_assia@yahoo.fr.
authors.forename: A
authors.initials: A
authors.lastname: Anane
authors.affiliation: Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté des Sciences Biologiques (FSB), Laboratoire de Recherche sur les Zones Arides, (LRZA), BP 32 El Alia 16111, Bab Ezzouar 16111, Algérie. Electronic address: amiratzaina@yahoo.fr.
authors.forename: Z
authors.initials: Z
authors.lastname: Amirat
authors.affiliation: Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté des Sciences Biologiques (FSB), Laboratoire de Recherche sur les Zones Arides, (LRZA), BP 32 El Alia 16111, Bab Ezzouar 16111, Algérie. Electronic address: faridakhammar@gmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Khammar
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D003577:Cytochrome P-450 Enzyme System; D004032:Diet / Q000662:veterinary; D005508:Food Deprivation; D015971:Gene Expression Regulation, Enzymologic; D006913:Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D007527:Isoenzymes; D020935:MAP Kinase Signaling System; D008297:Male; D009752:Nutritional Status; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D021122:Protein Subunits; D012756:Sheep / Q000254:growth & development / Q000378:metabolism*; D013737:Testis / Q000201:enzymology* / Q000378:metabolism; D013739:Testosterone / Q000097:blood / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D007527:Isoenzymes; D010750:Phosphoproteins; D021122:Protein Subunits; D000098682:Steroidogenic Acute Regulatory Protein; D013739:Testosterone; D003577:Cytochrome P-450 Enzyme System; D006913:Hydroxysteroid Dehydrogenases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases
keywords: AMPK; Diet; Domestic ruminant; Signal transduction; Steroidogenesis