Serum levels of progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones in the prepartum and postpartum equine

Steroids. 1979 Jan;33(1):55-63. doi: 10.1016/s0039-128x(79)80006-9.

Abstract

Blood samples were collected from eight mares for ten days before and two days following parturition. Progesterone, 5 alpha-dihydroprogesterone and hydroxy-5 alpha-pregnanones were extracted from serum, separated by Sephadex LH-20 column chromatography and quantitated by radioimmunoassay. Progesterone levels ranged from 8.5 to 4.1 ng/ml among mares with normal parturition and decreased to 1.2 ng/ml after parturition. One mare with a retained placenta maintained the prepartal levels of progesterone into the postpartum period. 5 alpha-dihydroprogesterone increased to a level of 133 ng/ml at 80 hrs before parturition and began decreasing and reached a level of 9.2 ng/ml in the postpartum period. Levels of hydroxy-5 alpha-pregnanones were variable with a high of 1690 ng/ml and declined to a postpartum level of 60 ng/ml. The timing of the decline varied among the mares. The possible source and significance of these progestins remain speculative.

Publication types

  • Comparative Study

MeSH terms

  • 20-alpha-Dihydroprogesterone / blood*
  • Animals
  • Female
  • Horses
  • Isomerism
  • Labor Onset
  • Labor, Obstetric
  • Pregnancy
  • Pregnancy, Animal*
  • Pregnanes / blood*
  • Pregnanolone / blood*
  • Progesterone / analogs & derivatives*
  • Progesterone / blood*
  • Time Factors

Substances

  • Pregnanes
  • 20-alpha-Dihydroprogesterone
  • Progesterone
  • Pregnanolone