TY - JOUR
T1 - Expression of key substrate cycle enzymes in rat spermatogenic cells
T2 - Fructose 1,6 bisphosphatase and 6 phosphofructose 1-kinase
AU - Yáñez, Alejandro J.
AU - Bustamante, Ximena
AU - Bertinat, Romina
AU - Werner, Enrique
AU - Rauch, Maria Cecilia
AU - Concha, Ilona I.
AU - Reyes, Juan G.
AU - Slebe, Juan C.
PY - 2007/9
Y1 - 2007/9
N2 - A substrate cycle composed of phosphofructo 1-kinase I (PFK) and fructose 1,6 bisphosphatase I (FBPase) has been proposed in rat spermatids. This substrate cycle can explain the ability of glucose to induce a decrease in intracellular ATP, a phenomenon that was related to regulation of [Ca 2+]i in these cells. In spite of the importance of this metabolic cycle, the expression and activities of the enzymes that compose such cycle have not been systematically studied in spermatogenic cells. Here, we show that PFK and FBPase activities were present in pachytene spermatocytes and round spermatids extracts. Expression of PFK at the mRNA and protein levels showed a relatively similar expression in spermatogenic cells, but a stronger expression in Sertoli cells. Instead, expression of FBPase at the mRNA and protein levels was stronger in round and elongating spermatids as compared to other spermatogenic cells. A similar pattern was observed when evidencing FBPase activity by a NADPH-nitroblue tetrazolium-linked cytochemical assay in isolated pachytene spermatocytes and round spermatids. Rat spermatids also showed the ability to convert lactate to fructose- and glucose-6-P, indicating that both glycolytic and gluconeogenic fluxes are present in these cells. Our results indicate that a coordinated expression of key substrate cycle enzymes, at the level of PFK/FBPase, appear in the last stages of spermatogenic cell differentiation, suggesting that the co-regulation of these enzymes are required for the ability of these cells to respond to glucose and induce metabolic and Ca2+ signals that can be important for sperm development and function.
AB - A substrate cycle composed of phosphofructo 1-kinase I (PFK) and fructose 1,6 bisphosphatase I (FBPase) has been proposed in rat spermatids. This substrate cycle can explain the ability of glucose to induce a decrease in intracellular ATP, a phenomenon that was related to regulation of [Ca 2+]i in these cells. In spite of the importance of this metabolic cycle, the expression and activities of the enzymes that compose such cycle have not been systematically studied in spermatogenic cells. Here, we show that PFK and FBPase activities were present in pachytene spermatocytes and round spermatids extracts. Expression of PFK at the mRNA and protein levels showed a relatively similar expression in spermatogenic cells, but a stronger expression in Sertoli cells. Instead, expression of FBPase at the mRNA and protein levels was stronger in round and elongating spermatids as compared to other spermatogenic cells. A similar pattern was observed when evidencing FBPase activity by a NADPH-nitroblue tetrazolium-linked cytochemical assay in isolated pachytene spermatocytes and round spermatids. Rat spermatids also showed the ability to convert lactate to fructose- and glucose-6-P, indicating that both glycolytic and gluconeogenic fluxes are present in these cells. Our results indicate that a coordinated expression of key substrate cycle enzymes, at the level of PFK/FBPase, appear in the last stages of spermatogenic cell differentiation, suggesting that the co-regulation of these enzymes are required for the ability of these cells to respond to glucose and induce metabolic and Ca2+ signals that can be important for sperm development and function.
UR - http://www.scopus.com/inward/record.url?scp=34547945656&partnerID=8YFLogxK
U2 - 10.1002/jcp.21077
DO - 10.1002/jcp.21077
M3 - Article
C2 - 17492776
AN - SCOPUS:34547945656
VL - 212
SP - 807
EP - 816
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
SN - 0021-9541
IS - 3
ER -