Comparison of Expression of Glucose, Fructose, and Cationic Amino Acid Transporters in Bovine Caruncular and Inter-Caruncular Tissue Between the Pregnant and Non-Pregnant Uterine Horn from Days 16 to 50 of Gestation

We hypothesized that day of gestation, maternal nutrition, and uterine horn, influence the mRNA expression of glucose, fructose, and cationic amino acid transporters in caruncular and inter-caruncular tissue from d 16 to 50 of gestation. Crossbred Angus heifers (n = 43) were estrus synchronized, bred via AI, assigned to nutritional treatment (CON = 100% of requirements for 0.45 kg/d gain and RES = 60% of CON), and ovariohysterectomized on d 16, 34, or 50 of gestation (n = 6 to 9/d). The resulting arrangement was a 2 × 3 factorial. Caruncles from the pregnant horn (P-CAR) and non-pregnant horn (NP-CAR), and inter-caruncular tissue from pregnant horn (P-ICAR) and non-pregnant horn (NP-ICAR) were obtained immediately following ovariohysterectomy. Relative gene expression of glucose transporters GLUT1, GLUT3, and GLUT14, fructose transporter GLUT5, and cationic amino acid transporters CAT-1, CAT-2, and CAT-3 were determined utilizing a non-bred heifer uterine sample as the baseline. No transporters were influenced by a day × horn × treatment interaction; therefore, data are reported for a day × horn interaction in caruncular and inter-caruncular tissue. Expression of GLUT1 was greater (P < 0.01) in P-CAR on d 16 compared with 34 and 50, and NP-CAR on all days. Relative expression of GLUT3 was greater (P < 0.01) in P-CAR on d 50 compared with 16 and 34, and NP-CAR on all days. Expression of GLUT14 was greater (P < 0.01) in P-CAR on d 50 compared with 16 and 34, and NP-CAR on all days. Relative expression of GLUT1 was greater (P = 0.04) in P-ICAR and NP-ICAR on d 16 compared with d 34 tissues. Expression of GLUT3 was greater (P = 0.04) in d 50 P-ICAR compared with NP-ICAR on d 16 and 50. Relative expression of CAT-1 was greater (P < 0.01) in NP-CAR on d 50 and P-CAR on d 34, compared with P-CAR and NP-CAR on d 16. In inter-caruncular tissue, CAT-1 was greater (P < 0.01) in P-ICAR on d 34 and 50, compared with P-ICAR and NP-ICAR on d 16. Expression of CAT-2 was greater (P = 0.05) in NP-ICAR on d 16 compared with NP-ICAR on d 34. Relative expression CAT-3 was greater (P = 0.02) in NP-ICAR on d 50 compared with NP-ICAR on d 34. We interpret these data to imply that day of gestation and presence of the embryo more greatly influenced gene expression than nutritional treatment.