Abstract
A direct radioimmunoassay for estrogen conjugates (EC) was applied to paired blood and urine samples collected from 20 mares and compared against estrone (E1) and estradiol-17β (E2) to monitor changes in estrogen production during ovulatory cycles and early pregnancy. Blood samples were taken daily from five mares through two consecutive ovulations and from six mares at 6-h intervals starting 48 hours prior to ovulation and continuing after ovulation had occurred. Blood samples were also collected daily or three times per week from conception until Day 60 of pregnancy in nine pregnant mares. The mean urinary EC, plasma EC and plasma E2 dynamics were parallel in nonpregnant mares, with a 3-fold increase in mean urinary EC concentrations from baseline to the ovulatory peak, a 1.8-fold increase in mean plasma EC concentrations and a 1.4-fold increase in mean plasma E2 concentrations. In early pregnancy, a two-fold increase in mean plasma E1 and EC concentrations occurred in concert with a five-fold rise in mean urinary EC concentrations, whereas plasma E2 did not change. Following hydrolysis and chromatographic separation, E1 and E2 were identified as the hydrolytic products in the urine of nonpregnant and pregnant mares; however, an unidentified estrogen was the major hydrolytic product in nonpregnant mares and pregnant mares prior to Day 38 of pregnancy. The increased resolution of the EC profiles compared with the profiles of other estrogen components indicates that the determination of EC in urine or plasma provides a useful alternative method for monitoring reproductive events in mares.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1001-1017 |
| Number of pages | 17 |
| Journal | Theriogenology |
| Volume | 35 |
| Issue number | 5 |
| DOIs | |
| State | Published - Jan 1 1991 |
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Keywords
- estrogen
- mare
- ovulation
- pregnancy
- urinary estrogen
ASJC Scopus subject areas
- Small Animals
- Food Animals
- Animal Science and Zoology
- Equine
Cite this
Urinary and plasma estrogen conjugates, estradiol and estrone concentrations in nonpregnant and early pregnant mares. / Daels, P. F.; Ammon, D. C.; Stabenfeldt, G. H.; Liu, Irwin; Hughes, J. P.; Lasley, B. L.
In: Theriogenology, Vol. 35, No. 5, 01.01.1991, p. 1001-1017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Urinary and plasma estrogen conjugates, estradiol and estrone concentrations in nonpregnant and early pregnant mares
AU - Daels, P. F.
AU - Ammon, D. C.
AU - Stabenfeldt, G. H.
AU - Liu, Irwin
AU - Hughes, J. P.
AU - Lasley, B. L.
PY - 1991/1/1
Y1 - 1991/1/1
N2 - A direct radioimmunoassay for estrogen conjugates (EC) was applied to paired blood and urine samples collected from 20 mares and compared against estrone (E1) and estradiol-17β (E2) to monitor changes in estrogen production during ovulatory cycles and early pregnancy. Blood samples were taken daily from five mares through two consecutive ovulations and from six mares at 6-h intervals starting 48 hours prior to ovulation and continuing after ovulation had occurred. Blood samples were also collected daily or three times per week from conception until Day 60 of pregnancy in nine pregnant mares. The mean urinary EC, plasma EC and plasma E2 dynamics were parallel in nonpregnant mares, with a 3-fold increase in mean urinary EC concentrations from baseline to the ovulatory peak, a 1.8-fold increase in mean plasma EC concentrations and a 1.4-fold increase in mean plasma E2 concentrations. In early pregnancy, a two-fold increase in mean plasma E1 and EC concentrations occurred in concert with a five-fold rise in mean urinary EC concentrations, whereas plasma E2 did not change. Following hydrolysis and chromatographic separation, E1 and E2 were identified as the hydrolytic products in the urine of nonpregnant and pregnant mares; however, an unidentified estrogen was the major hydrolytic product in nonpregnant mares and pregnant mares prior to Day 38 of pregnancy. The increased resolution of the EC profiles compared with the profiles of other estrogen components indicates that the determination of EC in urine or plasma provides a useful alternative method for monitoring reproductive events in mares.
AB - A direct radioimmunoassay for estrogen conjugates (EC) was applied to paired blood and urine samples collected from 20 mares and compared against estrone (E1) and estradiol-17β (E2) to monitor changes in estrogen production during ovulatory cycles and early pregnancy. Blood samples were taken daily from five mares through two consecutive ovulations and from six mares at 6-h intervals starting 48 hours prior to ovulation and continuing after ovulation had occurred. Blood samples were also collected daily or three times per week from conception until Day 60 of pregnancy in nine pregnant mares. The mean urinary EC, plasma EC and plasma E2 dynamics were parallel in nonpregnant mares, with a 3-fold increase in mean urinary EC concentrations from baseline to the ovulatory peak, a 1.8-fold increase in mean plasma EC concentrations and a 1.4-fold increase in mean plasma E2 concentrations. In early pregnancy, a two-fold increase in mean plasma E1 and EC concentrations occurred in concert with a five-fold rise in mean urinary EC concentrations, whereas plasma E2 did not change. Following hydrolysis and chromatographic separation, E1 and E2 were identified as the hydrolytic products in the urine of nonpregnant and pregnant mares; however, an unidentified estrogen was the major hydrolytic product in nonpregnant mares and pregnant mares prior to Day 38 of pregnancy. The increased resolution of the EC profiles compared with the profiles of other estrogen components indicates that the determination of EC in urine or plasma provides a useful alternative method for monitoring reproductive events in mares.
KW - estrogen
KW - mare
KW - ovulation
KW - pregnancy
KW - urinary estrogen
UR - http://www.scopus.com/inward/record.url?scp=0000913430&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000913430&partnerID=8YFLogxK
U2 - 10.1016/0093-691X(91)90310-A
DO - 10.1016/0093-691X(91)90310-A
M3 - Article
VL - 35
SP - 1001
EP - 1017
JO - Theriogenology
JF - Theriogenology
SN - 0093-691X
IS - 5
ER -