
TY  - JOUR
A1  - Whitely, JL 
A1  - Willcox, DL 
A1  - Newton, JA 
A1  - Bryant-Greenwood, GD 
A1  - Hartmann, PE 
T1  - Total and Free Plasma Concentrations of Progesterone, Cortisol and Oestradiol-I7ß during Pregnancy, Parturition and Early Lactation in Sows
JF  - Australian Journal of Biological Sciences
JO  - Aust. Jnl. Of Bio. Sci.
Y1  - 1984
VL  - 37
IS  - 4
SP  - 267
EP  - 276
KW  - 
UR  - https://doi.org/10.1071/BI9840267 
N2  - The total (bound plus free) concentrations of progesterone, 20a-<iihydroprogesterone, oestradiol-17{:1 and cortisol were determined in the plasma of sows at three stages during pregnancy and more intensively from 5 days pre-partum to 5 days post-partum. The free fractions of progesterone, oestradiol-17{3 and cortisol were measured in the same samples by a rate dialysis method. Up to day 110 of gestation, the amounts of free hormone in plasma did not fluctuate independently of their total concentrations. During farrowing, the total and free concentrations of progesterone and cortisol varied independently of each other, whereas total and free oestradiol-17{3 declined simultaneously. The initiation of parturition was associated with a decrease in circulating total progesterone, and was accentuated by a decrease in the free fraction (P<O· 005) so that its active free concentration was only 20% of its day 1 pre-partum value. Total and free cortisol concentrations rose rapidly during labour so that at 12-18 h after birth of the first piglet 30% of that cortisol in maternal plasma was free hormone. 
ER  -

