Gene expression of glucose transporter (GLUT) 1, 3 and 4 in bovine follicle and corpus luteum.
Glucose is the main energy substrate in the bovine ovary, and a sufficient supply of it is necessary to sustain the ovarian activity. Glucose cannot permeate the plasma membrane, and its uptake is mediated by a number of glucose transporters (GLUT). In the present study, we investigated the gene expression of GLUT1, 3 and 4 in the bovine follicle and corpus luteum (CL). Ovaries were obtained from Holstein x Japanese Black F1 heifers. Granulosa cells and theca interna layers were harvested from follicles classified into five categories by their physiologic status: follicular size (>or= 8.5 mm: dominant; < 8.5 mm: subordinate), ratio of estradiol (E(2)) to progesterone in follicular fluid (>or= 1: E(2) active;<1: E(2) inactive), and stage of estrous cycle (luteal phase, follicular phase). CL were also classified by the stage of estrous cycle. Expression levels of GLUT1, 3 and 4 mRNA were quantified by a real-time PCR. The mRNA for GLUT1 and 3 were detected in the bovine follicle and CL at comparable levels to those in classic GLUT-expressing organs such as brain and heart. Much lower but appreciable levels of GLUT4 were also detected in these tissues. The gene expression of these GLUT showed tissue- and stage-specific patterns. Despite considerable differences in physiologic conditions, similar levels of GLUT1, 3 and 4 mRNA were expressed in subordinate follicles as well as dominant E(2)-active follicles in both luteal and follicular phases, whereas a notable increase in the gene expression of these GLUT was observed in dominant E(2)-inactive follicles undergoing the atretic process. In these follicles, highly significant negative correlations were observed between the concentrations of glucose in follicular fluid and the levels of GLUT1 and 3 mRNA in granulosa cells, implying that the local glucose environment affects glucose uptake of follicles. These results indicate that GLUT1 and 3 act as major transporters of glucose while GLUT4 may play a supporting role in the bovine follicle and CL.
Nishimoto
H
H
Department of Agricultural and Life Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Matsutani
R
R
Yamamoto
S
S
Takahashi
T
T
Hayashi
K-G
KG
Miyamoto
A
A
Hamano
S
S
Tetsuka
M
M
D000818:Animals; D002417:Cattle / Q000378:metabolism*; D003338:Corpus Luteum / Q000737:chemistry / Q000378:metabolism*; D004958:Estradiol / Q000032:analysis; D030762:Estrous Cycle; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D015870:Gene Expression; D051246:Glucose Transport Proteins, Facilitative / Q000235:genetics*; D051272:Glucose Transporter Type 1 / Q000235:genetics; D051274:Glucose Transporter Type 3 / Q000235:genetics; D051275:Glucose Transporter Type 4 / Q000235:genetics; D006080:Ovarian Follicle / Q000737:chemistry / Q000378:metabolism*; D011374:Progesterone / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D051246:Glucose Transport Proteins, Facilitative; D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3; D051275:Glucose Transporter Type 4; D012333:RNA, Messenger; D011374:Progesterone; D004958:Estradiol