Steroidogenic capabilities of the early mouse embryo

Preimplantation embryos from ICR albino mice were used to determine progesterone and estradiol-17β production during incubation in BMOC-2. Following culture of 40 embryos/culture at either the morula, early blastocyst or late blastocyst stages, progesterone and estradiol-17β contents were 192±27 and 82±22 pg, 289±50 and 147±46 pg and 157±28 and 88±23 pg, respectively, for incubated samples and 306±68 and 89±40 pg, 404±63 and 125±44 pg, and 241±54 and 86±39 pg, respectively for control samples. Although, there were significant stage of development and treatments effects (P<0.05) for progesterone, production of this steroid was not evident. These data suggest that the early preimplantation mouse embryo does not produce progesterone or estradiol-17β in a defined culture system.     

Uptake and effects of ovarian steroids in the early pig embryo: In vitro and in vivo studies

The role of ovarian steroids in the preimplantation pig embryo was studied in vivo and in vitro. Twenty gilts were treated three times daily on days 1 to 4 after insemination with either 25, 100, 250, or 1000 mg progesterone in oil, and 17 gilts were injected with corresponding amounts of sesame oil (controls). All gilts were slaughtered 5 days after insemination and the embryos were recovered. Oviduct and plasma progesterone content were significantly (P<0.001) higher in gilts treated with 750 mg of exogenous progesterone per day. After 750 mg progesterone, oviduct progesterone content was twice as high as control levels, while after 3000 mg progesterone per day the levels in oviduct and uterus exceeded those of controls by five and seven times, respectively. In gilts treated with 750 mg progesterone per day, plasma progesterone levels were 177.4 ± 22.1 ng/ml ($\text{x}\text{±}\text{SD}$) on day 3 and 186.4 ± 69.2 ng/ml on day 5 and resembled values found in superovulated pigs with more than 40 ovulations. Excessive plasma progesterone values of 1014.6 ± 840.4 ng/ml on day 3 and 473.2 ± 197.2 ng/ml on day 5 were found after treatment with 3000 mg of progesterone per day. Treatment with up to 750 mg of exogenous progesterone per day, did not affect embryonic development, but 3000 mg per day resulted in a significantly (P<0.001) higher percentage of retarded and degenerate embryos compared to controls (71.8% versus 3.2%).In addition, the amount and specificity of uptake of ³H-labelled progesterone and estradiol-17 beta by pig blastocysts recovered from superovulated gilts were investigated after 6 hrs in vitro culture. The uptake of ³H-progesterone was 131.9 ± 56.9 counts per million (cpm) per 10 blastocysts, corresponding to 1.1 fmoles progesterone. The uptake was non-specific for it was only slightly reduced in the presence of a 100-fold excess of unlabelled progesterone (20.1%) or estradiol-17 beta (27.0%). The uptake of ³H-estradiol-17 beta was 133.9 ± 74.12 cpm per 10 blastocysts, corresponding to 1.3 fmoles estradiol-17 beta. The uptake was significantly (P<0.01) reduced by 67.7% in the presence of a 100-fold excess of unlabelled estradiol-17 beta. Apparent specific binding was 0.87 fmoles estradiol-17 beta per 10 blastocysts or 72.5 fmoles estradiol-17 beta per mg protein. The uptake was only slightly reduced in the presence of a 100-fold excess of unlabelled progesterone (23.3%). This significant inhibition could be determined after 2 hrs in vitro culture. There was no competitive inhibition after 20 min. of culture.Uptake by unfertilized ova and degenerate embryos recovered on day 5 was significantly smaller (51.8 ± 10.3 cpm per 10 eggs; P<0.001) than by blastocysts recovered on the same day. No competitive inhibition could then be determined. In vivo, preimplantation pig embryos seem to be rather insensitive to high progesterone levels. Excessive amounts of progesterone probably can be metabolized to a great extent. Progesterone seems to be taken up rather non-specifically by the pig embryo. The uptake and binding of estradiol-17 beta seems to be more specific. Studies are in progress to investigate the physiological role of estradiol-17 beta uptake in early embryonic development.     

Steroidal control of rat uterine 17β-hydroxysteroid dehydrogenase activity

The interconversion of estradiol-17β and estrone in the rat uterus is due to the action of 17β-hydroxysteroid dehydrogenase. Whole uteri or 800 × g supernatant fractions of the uteri were incubated in the presence of [³H] estradiol-17β and NAD at 37°C for 3 h or 1 h, respectively. In the mature rat uterus the oxidation of estradiol-17β and estrone was dependent on the stage of the estrous cycle, suggesting hormonal control. The 17β-hydroxysteroid dehydrogenase activity was highest at estrus (200 fmol estrone) and lowest at diestrus (80 fmol estrone). An enhancement of activity occurred when adult rats at each stage of the estrous cycle were administered estradiol-17β, while progesterone administration at each stage resulted in decreased enzyme activity. The uterine 17β-hydroxysteroid dehydrogenase activity of estradiol-17β treated ovariectomized rats was time and dose dependent but decreased when progesterone was administered with or without estradiol-17β administration. These results suggest that estradiol-17β caused an increase in enzyme activity that was inhibitable by progesterone in the rat uterus. The increased 17β -hydroxysteroid dehydrogenase activity may reflect a specific response of the rat uterus to estradiol-17β.     

Steroid hormones and the fertilizing capacity of spermatozoa

The effects of eleven different steroid hormones on $\text{in vitro}$ development of fertilizing capacity by hamster sperm were examined. Capacitation of epididymal sperm occurred only in the presence of female genital tract secretions. Fertilizing ability of sperm was poor if estradiol-17β, cortisol, chlormadinone acetate, medroxyprogesterone acetate, or megestrol acetate were present in the incubation medium at 10^?5M, whereas similar concentrations of estradiol-17α, progesterone, norethisterone acetate, ethynodiol diacetate, or norgestrel had little effect. Testosterone was a weak inhibitor of capacitation. Capacitation activity of female uterus and oviduct washings was higher at estrus than diestrus. This activity was reduced by treating intact animals with progesterone, cortisol, or testosterone, but increased by estradiol-17β or HCG. Estradiol-17α has no effect. Activity was low in pregnant or ovariectomized hamsters. Treatment of ovariectomized animals with estradiol-17β increased capacitation activity, but estradiol-17α, HCG or progesterone treatment was ineffective.     

The influence of estradiol-17beta and progesterone on peripheral serum concentrations of luteinizing hormone and follicle stimulating hormone in the ovariectomized ewe

Serum gonadotropin concentrations were high and variable and fluctuated episodically in short and long term ovariectomized ewes. Treatment with solid silastic implants releasing progesterone (serum levels 1.81 +/- 0.16 ng/ml) had no consistent effect. Treatment with implants releasing estradiol-17beta significantly depressed mean serum gonadotropin concentrations and peak height to values usually seen in intact ewes. This occurred regardless of implant size and serum estradiol-17beta concentrations (range 11 +/- 0.3 pg/ml to 98 +/- 12.8 pg/ml). Progesterone and estradiol-17beta together significantly depressed the frequency of peaks in LH concentration. Following progesterone removal, 95% of the ewes treated with progesterone and estradiol-17beta implants experienced a transient increase in serum LH concentrations similar to the preovulatory surge in intact ewes. Eighty-four percent of the LH surges were accompanied by a surge in serum FSH concentrations. However, following progesterone removal, 5.1 +/- 2.1 FSH surges were observed over six days. Gonadotropin surges occurred regardless of estradiol-17beta implant size and with or without the influence of supplemental estradiol-17beta.     

Hydrogen peroxide formation and lipid peroxidation in rat uterus—effect of hormones and vitamin E

The effect of estradiol-17β and progesterone given separately as well as in combination on the rate of hydrogen peroxide formation and lipid peroxidation in the uteri of ovariectomized rats was studied. Estradiol in 3μg dose per day per animal elicited maximum stimulatory response and progesterone (100μg), on the other hand, was without any such effect. However, progesterone given along with estradiol completely prevented the effect due to the latter. In the same way, vitamin E, a well known antioxidant was found to be extremelv effective in protecting the uterus from the highly peroxidative action of estradiol-17β.     

Sex hormones correlated with sex skin swelling and rectal temperature during the menstrual cycle of the pigtail macaque (Macaca nemestrina).

Daily measurement of serum luteinizing hormone, estradiol-17beta, and progesterone were made during the menstrual cycle in nine pigtail macaques (Macaca nemestrina). All data were normalized to the day of the luteinizing hormone peak. Serum estradiol-17beta increased from approximately 100 pg/ml during the early follicular phase to 442 +/- 156 pg/ml during the maximum midcycle concomitant with the luteinizing hormone peak, and a small increase in serum estradiol-17beta was observed during the luteal phase coincident with the progesterone peak. Serum progesterone values increased slightly at the time of the luteinizing hormone peak and increased from 0.2-0.3 ng/ml during the midfollicular phase to peak levels of 8.3 +/- 1.75 ng/ml 9 days after the luteinizing hormone surge. Serum luteinizing hormone remained low and relatively constant throughout the early and midcycle, then sharply increased approximately four-fold to peak values of 6.25 +/- 0.9 ng/ml. Sex skin swelling increased slowly during the follicular phase and declined slowly throughout the early luteal phase. Rectal temperature did not change significantly throughout the menstrual cycle. The similarity of plasma sex hormone changes during the menstrual cycle between women and the pigtail macaque suggested that this nonhuman primate should be a useful animal model for studying human reproduction.     

The solubilisation of some steroids by phosphatidylcholine and phosphatidylcholine-cholesterol vesicles.

The solubility of the three steroid hormones, progesterone, testosterone, and estradiol-17 beta in water and phosphatidylcholine vesicles was measured after shaking and ultrasonication. All three steroids have low water solubility, which increases considerably at sonication for testosterone and estradiol-17 beta. The phosphatidylcholine vesicles have a very small solubilising capacity for the steroids; about 20 mumol/mol. This increases at sonication for estradiol-17 beta and decreases for testosterone. The capacity for progesterone is almost unaltered. The incorporation of cholesterol in the vesicles decreased the solubilisation capacity for testosterone and estradiol-17 beta but increased that for progesterone of shaked preparations. For the sonicated systems the cholesterol decreased the solubilising capacity for estradiol-17 beta but increased that for testosterone. The solubilisation experiments indicate that the steroid hormones are solubilised in the hydrocarbon part of the phosphatidylcholine bilayer and also 13CNMR results support this conclusion.     

Concentrations of progesterone,testosterone and estradiol-17β in the serum during the estrous cycle of Asian elephants (Elephas maximus)

The levels of progesterone, testosterone and estradiol-17β in serum samples from two female Asian elephants were measured for the period of 32 months from February 1987 to September 1989. Serum samples were collected weekly from unanesthetized elephants. Each elephant showed eight ovarian cycles in 32 months. Ovarian cycles, characterized by changes in concentrations of serum progesterone, averaged 16.8 ± 0.6 (mean ± SEM. n = 14) weeks in length. The changes in concentrations of testosterone in the serum showed a similar pattern to those of progesterone with a striking increase noted during the luteal phase. The highest levels of serum estradiol-17β were noted when progesterone levels showed low basal values. These results suggest that estradiol-17β may be an index of follicular maturation during the estrous cycle in Asian elephants, and that the ovaries of Asian elephants may produce testosterone in the luteal phase.     

Differential hormonal regulation of leukemia inhibitory factor (LIF) in rabbit and mouse uterus

Leukemia inhibitory factor (LIF) has been shown to be essential for the implantation of mouse blastocysts. The present study was designed to determine how LIF protein was hormonally regulated in rabbit and mouse uterus using immunohistochemistry. In unmated rabbits, LIF protein was at a low level in the uterine epithelium and glands, and up-regulated by progesterone alone or estradiol-17β and progesterone combined. Estradiol-17β alone had no apparent effect. In ovariectomized mice, the level of LIF protein was very low in the uterine epithelium and glands, and was up-regulated by estradiol-17β alone or estradiol-17β and progesterone combined. Progesterone alone had no apparent effect. These results suggest that LIF protein is differentially regulated in rabbit and mouse uterus by progesterone and estrogen, respectively. This would explain the high level of LIF protein observed in uterine epithelium and glands prior to blastocyst implantation in the two species with different hormonal requirements for implantation. © 1996 Wiley-Liss, Inc.     

Serum LH,progesterone and estradiol-17β levels throughout the ovarian cycle,during the early stage of pregnancy and after the parturition and the abortion in the common marmoset,Callithrix jacchus

In the ovarian cycle of common marmosets, serum progesterone began to increase at two to three days after estradiol-17β or LH surge, attained a peak of 25–70 ng/ml and then declined to a level of under 2 ng/ml before the ensuing rise in estradiol-17β and LH. Serum estradiol-17β increased to 700–5,500 pg/ml during the luteal phase, synchronizing with progesterone. It is suggested that the corpus luteum secreted estradiol-17β as well as progesterone. The cycle length as determined from the interval between successive LH surges was approximately 28 days. During the luteal phase, the levels of progesterone and estradiol-17β were higher than in Old World monkeys and women, but marmosets were not accompanied by any clinical symptoms due to excessive progesterone and estradiol-17β. This suggests that such unresponsiveness to progesterone and estradiol-17β in marmosets reflects the small amount of estradiol-17β receptor and presumably also the lower function of the post receptor system. Recovery of the post-partum ovarian cycle in two marmosets differed from that observed in Old World monkeys and women. The first LH surge was found on the ninth and tenth day after parturition and the first ovulation led to the next pregnancy. This suggests that the suckling stimulus of newborns in the common marmoset does not cause any delay in recovery of the ovarian cycle. In three cases of abortion, the recovery of the ovarian cycle was almost the same as that in the case of normal parturition: the first LH surge appeared on the 10th, 14th, and 34th day after abortion.     

Ultrastructural changes in guinea pig endometrial cells during the estrous cycle.

In the guinea pig, the estrous cycle is characterized by a constant measurable level of plasma progesterone with two peaks: the first one associated with the peak of plasma estradiol-17 beta occurring at proestrus and the second, during diestrus, more pronounced at the time at which the level of estradiol-17 beta is undetectable. The progesterone receptor content is the highest on day 1 and the lowest on day 10 of the estrous cycle, which lasts 16.3 +/- 1.5 days (n = 37; mean +/- SD). There is a positive correlation between the plasma level of estradiol-17 beta and the progesterone receptors detected immunocytochemically in both endometrial epithelial and stromal cells. The general morphology of the endometrium during proestrus and estrus is consistent with an estrogenic stimulation, i.e., a smooth and regular surface of the endometrium and the presence of numerous microvilli on the cell surface. However, a moderate secretory activity also occurs in proestrus and estrus. During postestrus, the glandular cells display an increase in characteristic secretory features which parallels the rise of progesterone in the plasma.     

Effects of estrogen and progesterone on uterine sialic acid in ovariectomized rats

The effects of estradiol-17β and progesterone on uterine sialic acid of ovariectomized rats have been examined. In contrast to a previous report, progesterone was found in two of three experiments of different design to increase uterine sialic acid concentration above that produced by estradiol-17β alone; in the third experiment, it had no significant effect. This effect of progesterone was independent of the duration of treatment with exogenous hormones or of whether or not uterine luminal fluid was removed by blotting before assaying sialic acid. In a factorially designed experiment with four levels of estradiol-17β and three of progesterone, a dose-response relationship was found between estradiol-17β, but not progesterone, and uterine sialic acid concentration. It is concluded that, in some circumstances, estrogen and progesterone can act synergistically to increase uterine sialic acid concentration.     

Effect of the aromatase inhibitor CGS-16949A on pregnancy and secretion of progesterone, estradiol-17beta, prostaglandins E and F2alpha (PGE; PGF2alpha) and pregnancy specific protein B (PSPB) in 90-day ovariectomized pregnant ewes

The aromatase inhibitor CGS-16949A was used to determine whether CGS-16949A altered secretion of progesterone, estradiol-17beta, PGE (PGE1 + PGE2), PGF2alpha and PSPB. Ninety day pregnant ewes were ovariectomized and received vehicle, PGF2alpha, CGS-16949A or PGF2alpha+CGS-16949A. None of the ewes treated with PGF2alpha, CGS-16949A or PGF2alpha+CGS-16949A aborted (P > or = 0.05) during the 108-h experimental period. Treatment with CGS-16949A lowered (P < or = 0.05) progesterone in jugular venous plasma but concentrations of progesterone were not affected (P > or = 0.05) by treatment with PGF2alpha. Concentrations of estradiol-17beta and PSPB in jugular venous plasma and PGE in inferior vena cava plasma were decreased (P < or = 0.05) by treatment with CGS-16949A. Concentrations of PGF2alpha in inferior vena cava plasma were not affected (P > or = 0.05) by treatment with CGS-16949A. Decreases in estradiol-17beta occurred before decreases in PSPB, which was then followed by decreases in PGE (P < or = 0.05). It is concluded that these data support the hypothesis that estradiol-17beta regulates placental secretion of PSPB; PSPB regulates placental secretion of PGE; and PGE regulates placental secretion of progesterone during mid-pregnancy in ewes.     

Effect of prostaglandins on in vitro synthesis of progesterone and oestradiol-17 beta in placenta from early human pregnancy

In vitro synthesis of progesterone and estradiol-17 beta from endogenous precursors was studied in the placenta from women in early stage of gestation (less than 7 weeks). Radioimmunoassay techniques were used to measure progesterone and estradiol-17 beta. It was shown that placental tissue from as early as six weeks of gestation can synthesize both progesterone and estradiol-17 beta in vitro. Prostaglandins F2 alpha and E2 in concentration of 100 micrograms/ml of the incubation media did not have any significant effect on the in vitro synthesis of progesterone and estradiol-17 beta in the placental tissue. It seems unlikely that the abortifacient effect of natural prostaglandins PGE2 and PGF2 alpha is due to their direct action on the synthesis of progesterone and estradiol-17 beta in the placenta.     

大熊猫生殖生物学研究:Ⅰ.大熊猫发情期血清和尿液中促黄体素、孕酮和17β-雌二醇含量的变化

作者用放射免疫法和生物测定法对4只大熊猫发情期血清和尿液中的促黄体素、孕酮和17β-雌二醇的含量进行分析。结果表明:3只大熊猫在发情高峰期均出现雌二醇和促黄体素高峰;LH峰值出现在E_2峰值之后。根据雌兽在发情期血清和尿液中这二种激素含量的变化可为选择人工授精的最佳时间提供可靠的理论依据。     

Is the yak (Poephagus grunniens L.) really a seasonal breeder?

Yaks are considered to be seasonally polyestrous and breeding occurs from July to November. Here we show that some yaks in peak non-breeding season do exhibit cyclic luteal activity without exhibiting any behavioral signs around expected estrus. A total of eight non-lactating yaks were selected from the Yak Farm belonging to National Research Centre on Yak for various sets of experiments. The animals were maintained as per semi range system of management. They were allowed to graze during daytime and fed concentrate mixture @2 kg/animal/day as per standard farm practices of the center. Blood samples were collected on alternate days for 30 days by jugular venipuncture from the yaks during peak breeding season (July to November) and from the same yaks in non-breeding season (February to March). The plasma samples were analysed for progesterone and estradiol-17beta by RIA and EIA procedures, respectively. During breeding season, the mean plasma progesterone at estrus was basal (相似文献   

Serum LH,FSH, estradiol-17β and progesterone profiles of native and crossbred goats in a tropical semiarid zone of Venezuela during the estrous cycle

The patterns of serum luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone and estradiol-17β during the estrous cycle of six crossbred (Alpine × Nubian × Native) and six native goats showing a 21 day estrous cycle in a semiarid zone of Venezuela are presented. In the crossbred goats, FSH had two significant peaks on Days 19 and 0 (33 ± 8.6 ng ml⁻¹ and 25 ± 6 ng ml⁻¹, respectively); in contrast, native goats only had one significant peak on the day of estrus (22 ± 2 ng ml⁻¹), with the increase beginning on Day 17. During the follicular phase of crossbred goats, estradiol-17β and LH increased to 28 ± 6 pg ml⁻¹ and 23 ± 6.9 ng ml⁻¹, respectively, on Day 0. Prior to Day 0, LH increased to 10.0 ± 4.9 ng ml⁻¹ on Day 18, decreasing to 1.5 ng ml⁻¹ on Day 19, while estradiol-17β was increasing. This relationship between estradiol-17β and LH was not found to exist in native does, which presented a LH peak on Day 0 (30 ± 8 ng ml⁻¹ and 35 ± 10 ng ml⁻¹ in first and second estrus, respectively). LH basal levels were notably higher in native does. The highest concentrations of progesterone (10 and 12 ng ml⁻¹) were detected on Days 12 and 15 in crossbred and native females, respectively. In conclusion, the relationship between estradiol-17β and gonadotropins during the follicular phase in crossbred goats suggests negative and positive feedback effects on both LH and FSH. Serum concentrations of LH were higher in native than in crossbred goats, whereas concentrations of FSH were higher in crossbred does. Thus, genetic factors need to be taken into account when comparing blood levels of gonadotropins in goats raised in tropical semiarid zones.     

Progesterone and estradiol-17beta in the peripheral plasma of Brahman cows with single and twin pregnancies

Peripheral plasma samples from Brahman cows with single and twin pregnancies were assayed for progesterone and estradiol-17beta throughout pregnancy. The twin pregnancies were obtained by transfer of Friesian embryos to inseminated single-ovulating Brahman cows. The twin-bearing cows had significantly higher levels of progesterone at 8 and 36 weeks of pregnancy. There were no differences in estradiol-17beta levels until the pre-parturient rise which occurred earlier in twin pregnancies. Intra-muscular injection of progesterone had no measurable effect on peripheral plasma levels of estradiol-17beta in Charolais cows 31 - 32 weeks pregnant.     

Effect of prostaglandins on in vitro synthesis of progesterone and oestradiol-17β in placenta from early human pregnancy

In vitro synthesis of progesterone and estradiol-17β from endogenous precursors was studied in the placenta from women in early stage of gestation (< 7 weeks). Radioimmunoassay techniques were used to measure progesterone and estradiol-17β.It was shown that placental tissue from as early as six weeks of gestation can synthesize both progesterone and estradiol-17β in vitro. Prostaglandins F_2α and E₂ in concentration of 100 μg/ml of the incubation media did not have any significant effect on the in vitro synthesis of progesterone and estradiol-17β in the placental tissue.It seems unlikely that the abortifacient effect of natural prostaglandins PGE₂ and PGF_2α is due to their direct action on the synthesis of progesterone and estradiol-17β in the placenta.