Certain physiochemical properties of uterine tubal fluid, follicular fluid, and blood plasma in the mare.

Uterine tubal fluids were collected twice a day from mares for 5 consecutive estrous cycles between March 15 and September 1. Follicular fluids were aspirated from the follicles of exteriorized ovaries of 3 mares between days 2 and 5 of estrus. Uterine tubal fluid and follicular fluid were analyzed for osmolarity, dry matter, total lipids, total free fatty acids, glucose, fructose, and lactic acid. Blood samples were collected (jugular venipuncture) throughout the estrous cycle, and the same physical and biochemical analyses were made on blood plasma. A difference (P less than 0.01) was found for osmolarity between uterine tubal fluids collected during estrus and those collected during anestrus. The osmolarity of uterine tubal fluid during anestrus was greater than that of blood plasma; follicular fluid was similar in osmolarity to blood plasma. The dry matter in blood plasma was greater (P less than 0.01) than that in either uterine tubal fluid or follicular fluid. Cyclic variations in dry matter content were not observed in uterine tubal fluid. Total lipids in blood plasma and follicular were greater (P less than 0.01) than those in uterine tubal bluid. The concentration of total lipid in uterine tubal fluid was similar during estrus and anestrus. Myristic acid (C14:0) in blood plasma and myristoleic acid (C14:1) in uterine tubal fluid were the only free fatty acids that had cyclic variation. The fatty acids in the greatest concentration in uterine tubal fluid and blood plasma were palmitic acid (C16:0) and linoleic acid (C18:2). Concentrations of linoleic acid and stearic acid (C18:0) were greater (P less 0.01) in follicular fluid than in uterine tubal fluid or blood plasma. Only trace amounts of glucose were detected in uterine tubal fluid, whereas a considerable amount of glucose was found in follicular fluid. Fructose was not detected in any of the fluids. Lactic acid concentrations did not differ between estrus and anestrus. Lactic acid concentration was significantly greater (P less than 0.01) in uterine tubal fluids and follicular fluids than in blood plasma.