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Topic:Pregnant Mares' Serum Gonadotropin
Pregnant Mares' Serum Gonadotropin (PMSG), also known as equine chorionic gonadotropin (eCG), is a hormone produced by the endometrial cups of pregnant mares. This hormone is primarily responsible for stimulating ovarian follicular development and supporting the formation of secondary corpora lutea during early gestation in horses. PMSG has both luteinizing and follicle-stimulating hormone activity, contributing to the maintenance of pregnancy. In veterinary and reproductive studies, PMSG is utilized to induce estrus and ovulation in various animal species due to its gonadotropic properties. This page compiles peer-reviewed research studies and scholarly articles that explore the biological function, application, and effects of Pregnant Mares' Serum Gonadotropin in equine reproduction and management.
The ultrastructure of endometrial cups in pregnant mares. Electron microscopy and immunofluorescence techniques were used to study the various epithelial cells in the endometrial cups of ten pregnant mares, and in the uterine epithelium of one non-pregnant mare. Evidence was obtained which suggested that epithelial gland cells within the endometrial cups, as distinct from the hypertrophied decidual-like cells in the cup, may synthesize PMSG. The suggestion does not agree with the findings of other workers in the fetal origin (chorionic girdle cells) of this gonadotrophin.
Observations on reproductive performance in the yearling mare. Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between Days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregn...
Origin and histogenesis of equine endometrial cups. Biochemical and morphological studies were carried out to determine the origin and histogenesis of endometrial cups in mares. A wide range of fetal and maternal tissues were cultured in vitro and their ability to secrete gonadotrophin (PMSG) was monitored. High levels of PMSG were produced in culture only by cells from the restricted area of the equine trophoblast known as the chorionic girdle which is an annular band of highly specialized cells at the junction of the allantois and the regressing yolk sac. The morphological appearance of girdle cells after cultivation in vitro and after alloge...
Ovarian changes during early pregnancy in pony mares in relation to PMSG production. The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.
The influence of fetal genotype upon endometrial cup development and PMSG and progestagen production in equids. The influence of fetal genotype upon gonadotrophin (PMSG) and progestagen production in mares and donkeys during the first half of pregnancy was examined. The production of PMSG was greatly reduced in mares carrying mule conceptuses and greatly increased in donkeys carrying hinny conceptuses. Fetal genotype had no obvious influence upon progestagen production in mares, but donkeys carrying hinny conceptuses showed extremely high peripheral plasma progestagen concentrations when serum PMSG levels were elevated. Fetal genotype profoundly influences the intensity and rate of success of the matern...
[The effect of pregnant mare’s serum on the level of K+ ions in the immature rat ovary]. Pregnant Mare Serum Gonadotrophin enhanced potassium level in immature rat ovaries in comparison with controls, three hours after intravenous injection. In vivo 42K uptake was also 36% higher (p less than or equal to 0,01) in PMSG primed rat ovaries. This response was specific to the ovary. Experiments are carried out to determine correlation between K+ level and macromolecule biosynthesis.
Pregnant mare serum gonadotrophin: rate of clearance from the circulation of sheep. The process involved in the disappearance of PMSG from the blood of sheep, following a single intravenous injection, has been separated into two exponential components. Values (mean plus or minus S.E.) calculated from experiments on five animals were: metabolic clearance rate (37.8 plus or minus 1.6 ml hr-minus 1); rate constant of disposal (0.0315 plus or minus 0.0016 hr-minus 1); half-time of disposal (21.2 plus or minus 1.1 hr). The stage of the oestrous cycle, ovariectomy and the dose of PMSG used had no apparent effect on these values.
Purification and physicochemical properties of the pregnant mare serum gonadotropin (PMSG). A highly purified preparation of PMSG has been obtained from fresh serum and from a commercial preparation. Carbohydrate and amino acid compositions have been determined. The carbohydrate content of PMSG is 46.7% and the molecule is rich in Sialic Acid (13.5%). The apparent molecular weight of PMSG has been determined by SDS polyacrylamide gel electrophoresis. A molecular weight of 53,000 has been found for the unreduced and unalkylated molecule. After reduction and alkylation, the molecular weight fell to 23,000. From these values it has been concluded that PMSG is an oligomeric molecule comp...
Ovarian response of cows following pregnant mare serum gonadotrophin treatment during two successive estrous cycles. Thirteen cows (8 Holsteins, 3 Ayrshire,
2 Shorthorn; 3 to 7 years old) were
treated with pregnant mare serum gonadotrophin (PMSG) during two successive
estrous cycles. The gonadotrophin was
injected on Day 16 of the cycle (estrus ---
Day 0) and again on Day 16 of the next
cycle (10 cows) or 21 days after previous
PMSG injection (3 cows). Doses of
PMSG injected during the first cycle were
3,000 IU (6 cows: Group A) and 2,000
IU (7 cows: Group B). These doses were
reversed for the individual cow during
its next estrous cycle. Cows were
slaughtered 10 to 14 days after the second
PMS...
Chemical and immunochemical studies on pregnant mare serum gonadotropin. Highly purified pregnant mare serum gonadotropin (PMSG) can be prepared from crude commercial preparations of PMSG by chromatography on sulfoethyl-Sephadex C-50 and gel filtration on Sephadex G-100. The preparation was examined by disc electrophoresis and gel filtration and found to be of high purity. Amino acid analysis shows similarities to pituitary gonadotropins. The PMSG contains a high content of proline and cystine and low amounts of the aromatic amino acids. Phenylalanine is the major amino terminal amino acid. The carbohydrate content totals 45% of which 10% is the content of sialic a...
Field studies of an attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). A series of field studies using strain TC-83 attenuated Venezuelan equine encephalomyelitis vaccine in horses was made to determine the rate of seroconversions, the postvaccination viremia, and the possibility of adverse reactions to the vaccine. The rate of seroconversions varied from 50% in one study to 91 and 100% in two others. The highest level of viremia measured was 7 x 10(3) to 8 x 10(3) plaqueforming units per ml. No adverse reactions to the vaccine were observed in any horses, including 42 pregnant mares and their resulting foals.
