Molecular mechanisms involved in Sertoli cell adaptation to glucose deprivation.
Sertoli cells provide the physical support and the necessary environment for germ cell development. Among the products secreted by Sertoli cells, lactate, the preferred energy substrate for spermatocytes and spermatids, is present. Considering the essential role of lactate on germ cell metabolism, it is supposed that Sertoli cells must ensure its production even in adverse conditions, such as those that would result from a decrease in glucose levels in the extracellular milieu. The aim of the present study was to investigate 1) a possible effect of glucose deprivation on glucose uptake and on the expression of glucose transporters in rat Sertoli cells and 2) the participation of different signal transduction pathways in the above-mentioned regulation. Results obtained show that decreasing glucose levels in Sertoli cell culture medium provokes 1) an increase in glucose uptake accompanied by only a slight decrease in lactate production, 2) an increase in GLUT1 and a decrease in GLUT3 expression, and 3) an activation of AMP-activated protein kinase (AMPK)-, phosphatidylinositol 3-kinase (PI3K)/PKB-, and p38 MAPK-dependent pathways. Additionally, by using specific inhibitors of these pathways, a possible participation of AMPK- and p38MAPK-dependent pathways in the regulation of glucose uptake and GLUT1 expression is shown. These results suggest that Sertoli cells adapt to conditions of glucose deprivation to ensure an adequate lactate concentration in the microenvironment where germ cell development occurs.
Riera
María F
MF
Centro de Investigaciones Endocrinológicas, Hospital de Niños Ricardo Gutiérrez, Buenos Aires, Argentina.
Galardo
María N
MN
Pellizzari
Eliana H
EH
Meroni
Silvina B
SB
Cigorraga
Selva B
SB
D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D005947:Glucose / Q000172:deficiency* / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative / Q000096:biosynthesis; D051272:Glucose Transporter Type 1 / Q000096:biosynthesis / Q000378:metabolism; D051274:Glucose Transporter Type 3 / Q000096:biosynthesis / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D051246:Glucose Transport Proteins, Facilitative; D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3; C495679:Slc2a1 protein, rat; C495690:Slc2a3 protein, rat; D019344:Lactic Acid; D003847:Deoxyglucose; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose