Variations of Serum Estradiol and Progesterone Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

Abstract

Serum estradiol (E2) and progesterone (P4) levels were measured by chemiluminescence immunoassay (CLIA) during consecutive reproductive states in Mongolian gerbils. The results show that E2 and P4 levels throughout the estrous cycle in Mongolian gerbils peaked at proestrus and estrus, respectively. During gestation in primiparous and multiparous gerbils, E2 levels reached a small peak on day 6 and a maximum peak on day 21, followed by a slight decline until parturition. Thereafter, they dropped sharply during the first 3 days of lactation and remained stable until lactation ended. P4 levels reached a peak on day 12 during gestation in primiparous gerbils, while they peaked on day 6 in multiparous gerbils. The levels of P4 then decreased until parturition. During lactation, P4 levels peaked on day 9 in primiparous gerbils, while they peaked on day 6 in multiparous gerbils, and then the levels declined gradually until lactation ended. The findings suggest that the variations of E2 levels during the estrous cycle, gestation and lactation in Mongolian gerbils are similar to those observed in rats and mice. Changes in E2 levels during different reproductive states were the same in the primiparous and multiparous gerbils, but the variations in P4 levels did not display this tendency. Changing patterns of E2 and P4 levels are suitable for the reproductive stages of Mongolian gerbils.

The Effects of Quinestrol as a Contraceptive in Mongolian Gerbils (Meriones unguiculatus)

“…However, the P4 levels during the first half of gestation in quinestrol-treated Mongolian gerbils were lower than those in the control group. A rise in E2 and a decline in P4 are required for parturition initiation in Mongolian gerbils [21]. However, in the present study, the E2 levels in the quinestrol-treated groups were lower than in the control group from day 18 to 24 during gestation.…”

“…Changing patterns of E2 and P4 levels are correlated with the reproductive stages of Mongolian gerbils [21]. A higher P4 level during the first half of gestation is important for successful pregnancy in Mongolian gerbils [15,21]. However, the P4 levels during the first half of gestation in quinestrol-treated Mongolian gerbils were lower than those in the control group.…”

“…Estradiol and progesterone are important reproductive hormones during gestation. Changing patterns of E2 and P4 levels are correlated with the reproductive stages of Mongolian gerbils [21]. A higher P4 level during the first half of gestation is important for successful pregnancy in Mongolian gerbils [15,21].…”

“…The intra-and interassay variations for FSH and LH were 4.8 and 7.4%, respectively. Serum E2 and P4 levels were determined by a chemiluminescence immunoassay (CLIA) [21] using CLIA kits (Furui Biotechnology Co., Ltd., Beijing, China). The minimum detectable dose was 1.50 pg/ml for estradiol and 0.05 ng/ml for progesterone.…”

Variations in Serum Gonadotropin and Prolactin Levels during Consecutive Reproductive States in Mongolian Gerbils (Meriones unguiculatus)

“…The estrous cycle of the Mongolian gerbil is 4-7 days; gestation, 24-26 days; lactation, 21-22 days; and the litter size at birth ranges from 1-9 [9, 10, -Original- 18,25]. We have previously reported the changes in the levels of estradiol and progesterone during the different reproductive states in Mongolian gerbils [15]. However, data on the secretion patterns of reproductive hormones in Mongolian gerbils during different reproductive states remain insufficient [4,9,10,25,27].…”