Oestrogens, LH, PMSG, and prolactin in serum of pregnant mares.

The research article focuses on measuring the levels of various hormones, such as oestrogens, LH, PMSG, and prolactin, present in the serum of pregnant mares using radioimmunoassay.

Methods and Findings

• The study used radioimmunoassay, a method that uses antibodies to measure substances in the body, to identify levels of oestrone, equilin and equilenin (E1), oestradiol (E2), luteinizing hormone (LH), pregnant mare serum gonadotropin (PMSG), and prolactin in the serum of pregnant mares.
• The researchers found that E1 levels were higher than E2 levels throughout the pregnancy. Both E1 and E2 were observed to be at low levels until Day 80 of the pregnancy, increasing significantly by Day 120 to reach peak levels at Day 210 or 240 and then declining until birth.
• The maximum levels recorded for these hormones were 828 +/- 151 pg/ml for E1 and 71 +/- 18 pg/ml for E2 on the 210th and 240th days of pregnancy, respectively.

LH, PMSG, and Prolactin Levels

• Spikes in the LH hormone, which assists in ovulation and egg release, were observed in the pregnant mares during the early stages of pregnancy.
• Levels of PMSG, often used in veterinary medicine to induce ovulation, were first detectable on Days 32 or 36 of the pregnancy and reached a peak of 67-1 i.u./ml 64 days after the last mating event.
• From Day 210 of gestation until parturition, LH levels were found to be very low, often non-detectable.
• The levels of prolactin, a hormone that plays vital roles in reproduction and lactation, showed extreme variability throughout the pregnancy, with no clear patterns of fluctuation being observed.