Comparison of glucose, fructose, ascorbic acid and glucosephosphate isomerase enzymatic activity in uterine flushings from nonpregnant and pregnant gilts and pony mares.
Abstract: In Experiment 1, 40 gilts and 30 pony mares were used to characterize changes in glucose, fructose, ascorbic acid and glucosephosphate isomerase (GPI) enzymatic activity in uterine flushings collected either during the estrous cycle or early pregnancy. Total recoverable glucose was greater (P less than 0.01) in uterine flushings from pregnant gilts, but pregnancy status had no effect on total recoverable glucose in pony mare uterine flushings. Fructose was undetectable in uterine flushings from nonpregnant gilts and pony mares and pregnant gilts and pony mares prior to Day 14, but occurred in increasing amounts between Days 14 and 18 or 20 of pregnancy. In Experiment 2, it was demonstrated that the porcine conceptus is the primary source, if not the sole source of fructose. Total recoverable ascorbic acid in uterine flushings was not affected by pregnancy in gilts, but was greater (P less than 0.01) in pregnant versus nonpregnant pony mares. In both species, total recoverable ascorbic acid was affected (P less than 0.01) by day of the estrous cycle and pregnancy. The GPI enzyme allows for the interconversion of glucose-6-PO4 and fructose-6-PO4. GPI total and specific activities were greater (P less than 0.01) for pregnant than nonpregnant gilts and pony mares. The periods of greatest GPI activity were temporally associated with elevated estrogens of either ovarian or blastocyst origin. Results from Experiment 3 indicated a marked increase (P less than 0.01) in GPI activity in uterine flushings from gilts treated with estradiol valerate. Results of this study indicate that glucose (gilt only), fructose, ascorbic acid and GPI activity are increased in uterine flushings of gilts and pony mares during early pregnancy. The increase in these constituents may reflect increased carbohydrate metabolism in ways which are uniquely beneficial to conceptus development in ungulates.
Publication Date: 1982-12-01 PubMed ID: 7159659DOI: 10.1095/biolreprod27.5.1147Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research investigates how glucose, fructose, ascorbic acid (vitamin C) and glucosephosphate isomerase (an enzyme) concentrations vary in the uterine fluids of pregnant and nonpregnant pigs and ponies. The study found that the level of these substances generally increases during early pregnancy which may suggest unique roles in fetus development.
Details of the Experiment
- The experiment engaged two groups of subjects—40 gilts (female pigs) and 30 pony mares. The researchers aim was to find any changes in concentration levels of glucose, fructose, ascorbic acid and glucosephosphate isomerase (a type of enzyme) in uterine fluids during the menstrual cycle or early pregnancy.
- For the gilt group, it was discovery that there was more glucose present in pregnant subjects than non-pregnant ones, but no such difference was observed in pony mares. Fructose was not detectable until at least 14 days into pregnancy in both gilts and pony mares.
- In the second part of the experiment, it was found that the porcine conceptus (developing pig fetus) is possibly the only source of fructose in the uterine fluids.
Ascorbic Acid and Enzyme Activity
- Regarding ascorbic acid, its concentration level in uterine fluids was not affected by pregnancy in gilts, but was higher in pregnant pony mares versus nonpregnant ones.
- On both species, the concentration of ascorbic acid in uterine fluids was affected by the day of the menstrual cycle as well as by pregnancy.
- Glucosephosphate isomerase (GPI), an enzyme that facilitates an inter-conversion between glucose-6-PO4 and fructose-6-PO4, showed higher total and specific activities in pregnant farm animals.
Estrogen and GPI Activity
- The periods of high enzyme activity correlated with periods of high estrogen, a hormone which could be from either the ovaries or the blastocyst (the stage of embryo development before implantation).
- The third part of the experiment revealed higher GPI activity in gilts treated with a type of estrogen called estradiol valerate.
Conclusions of the Study
- The study concluded that the amounts of glucose (in gilts only), fructose, ascorbic acid, and GPI activity in uterine fluids increase during early stages of pregnancy.
- The researchers suggest that the increase in these substances may reflect greater carbohydrate metabolism, which might be uniquely beneficial to ungulate fetus development (ungulates are a group of large mammals which include horses and pigs).
Cite This Article
APA
Zavy MT, Clark WR, Sharp DC, Roberts RM, Bazer FW.
(1982).
Comparison of glucose, fructose, ascorbic acid and glucosephosphate isomerase enzymatic activity in uterine flushings from nonpregnant and pregnant gilts and pony mares.
Biol Reprod, 27(5), 1147-1158.
https://doi.org/10.1095/biolreprod27.5.1147 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Ascorbic Acid / metabolism
- Carbohydrate Metabolism
- Estrus
- Female
- Fructose / metabolism
- Glucose / metabolism
- Glucose-6-Phosphate Isomerase / metabolism
- Horses / metabolism
- Pregnancy
- Pregnancy, Animal
- Uterus / metabolism
Grant Funding
- HD 08560 / NICHD NIH HHS
Citations
This article has been cited 4 times.- Moses RM, Kramer AC, Seo H, Wu G, Johnson GA, Bazer FW. A Role for Fructose Metabolism in Development of Sheep and Pig Conceptuses. Adv Exp Med Biol 2022;1354:49-62.
- Vallet JL, Miles JR, Freking BA, Meyer S. Glucosamine supplementation during late gestation alters placental development and increases litter size. J Anim Sci Biotechnol 2017;8:68.
- Johnson GA, Minela T, Seo H, Bazer FW, Burghardt RC, Wu G, Pohler KG, Stenhouse C, Cain JW, Seekford ZK, Soffa DR. Conceptus Elongation, Implantation, and Early Placental Development in Species with Central Implantation: Pigs, Sheep, and Cows. Biomolecules 2025 Jul 17;15(7).
- Chen Z, Dean M. Endometrial Glucose Metabolism During Early Pregnancy. Reprod Fertil 2023 Nov 1;4(4).
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