Uptake Of Progesterone Research Articles

Mammary uptake and metabolism of progesterone in goats and its effect on milk progesterone concentrations during the oestrous cycle and early pregnancy.

Following the observation that the concentration of progesterone in goats' milk differs appreciably according to the specificity of the antiserum used in a non-extraction (direct) radioimmunoassay, experiments were carried out to find an explanation for these results. Milk and plasma samples were collected during the oestrous cycle and during an equivalent period of pregnancy after a fertile mating. Samples were analyzed by a direct radioimmunoassay using two antisera, 18/3 which is highly specific for progesterone and 465/6 which is less specific, and by radioimmunoassay of fractions isolated by thin-layer chromatography (TLC). Values obtained for milk and plasma samples collected during the oestrous cycle and early pregnancy were similar, except that values for milk samples measured with antiserum 465/6 were higher in pregnancy compared to those obtained during the oestrous cycle. Values obtained for milk and plasma with antiserum 465/6 were significantly higher than those obtained with 18/3 (P less than 0.001). After TLC this difference was found to be due principally to the presence of compound(s) with chromatographic properties identical to 5-pregnanedione(s). A comparison of the concentration measured in arterial and mammary venous plasma and in milk showed that about 25% of progesterone (5.7 nmol/min) was extracted by the mammary gland, and that substantial amounts of immunoreactive metabolites of progesterone are secreted into milk with only small quantities being transferred into mammary vein plasma.

Progesterone Uptake and Metabolism by the Goat Mammary Gland During Lactogenesis

SUMMARY Progesterone concentration was determined in carotid arterial and mammary venous plasma, and in mammary secretions from late pregnant goats. Two different anti-progesterone antisera were used; a specific antiserum showed that there was a large disparity between measurements of mammary progesterone uptake from blood (32·6 ± 3·1 μg/h) and output into milk (57·5 ± 9 ng/h). The progesterone concentration in mammary secretion determined with a less specific antiserum (2·22 ± 0·15 ng/ml) was significantly higher than that observed using the specific antiserum (0·25 ± 0·02 ng/ml) (P

In vitro uptake of estradiol and progesterone in the hamster uterus relative to the time of embryo transfer and stage of development.

Abstract The normal time for cleavage to the 2- and 8-cell stages of development of naturally ovulated hamster embryos is 25–27.5 and 59–61 h respectively, after ovulation and mating. The corresponding values for PMS-hCG treated hamsters were 33–35.5 and 62–64 h respectively. When 2-cell embryos, obtained by this timing method, were transferred to the oviductal bursa on Day 2 of the cycle, and when 8-cell embryos were transferred to the uterus on Day 3 of the cycle, implantation rates of 61.5 and 64.0% respectively, were obtained. The current study was conducted to determine the effects of transfer on estradiol and progesterone uptake by the uterine tissue on Day 14 after mating. A 2-fold increase in estradiol uptake was observed in superovulated, nonpregnant uteri when compared with nonsuperovulated animals. This level was also significantly higher than with nonsuperovulated pregnant animals and of animals receiving 2-cell embryo transfers. Estradiol uptake increases of 3.2 and 1.2-fold were noted for animals receiving 8-cell embryo transfers in naturally and superovulated groups respectively. Superovulation resulted in increased progesterone uptake. Transfer of 2- and 8-cell embryos resulted in a 15.8 and 109.9% increase in progesterone uptake respectively in naturally ovulated hamsters. Similar values for superovulated hamsters were 16.2 and 87.6% respectively. The 8-cell embryos, however, were transferred about four hrs prior to the time for normal 8-cell cleavage and this, coupled with increased estradiol uptake by the embryos themselves, resulted in an elevated estradiol and progesterone uptake in the uterine tissue even when measured on Day 14 of pregnancy. The degree of increase was less with superovulated animals receiving 8-cell embryos, reflecting higher levels of estradiol and progesterone uptake in control tissues. This could account for the slight delay in development of superovulated embryos.

Specific binding of progesterone to the cell surface and its role in the meiotic divisions in Rana oocytes

Progesterone is believed to act at the cell surface to induce the resumption of the meiotic divisions in amphibian oocytes. Analysis of [ 3H]- and [ 14C]progesterone uptake and exchange by the plasma-vitelline membrane complex, nucleus and cytoplasm of the isolated Rana oocyte indicates that progesterone uptake by the plasma membrane is saturable, specific and temperature-dependent, and has a slow off-rate. Estradiol (a noninducer) did not compete with progesterone, whereas testosterone (an inducer) blocked progesterone uptake by the membrane complex. Scatchard-type plots indicate an apparent K d of 5.1·10 −7 M over the [progesterone] o range of 0.01–1.0 μM with maximum binding at about 70 fmol per oocyte. Membrane uptake at higher [progesterone] o (2–40 μM) indicates apparent cooperative binding, with saturation up to 10 pmol per oocyte. Cytoplasmic uptake was apparently nonspecific and less temperature-dependent than membrane uptake and steroid concentrations (progesterone and pregnanediones) exceeded water solubility by 30–60 min. Nuclear uptake was saturable and specific but uptake was independent of temperature. A comparison of membrane binding and a physiological response (nuclear breakdown) indicated only about 10% of the membrane sites need be filled to initiate a 50% response.

The effect of prostaglandins on progestin receptor translocation and on decidual cell reaction in vivo and in vitro.

The ability of indomethacin, an inhibitor of prostaglandin (PG) synthesis, to modify the decidual cell reaction and nuclear uptake of progesterone in the uterus of pseudopregnant rats was studied in vivo and in vitro. Intraperitoneal administration of the drug (5 mg/kg) on the third or fourth day of leukocytic vaginal smear (days L3 or L4, respectively) suppressed the trauma-induced formation of deciduomata in vivo, but treatment on day L5, 24 h after application of the deciduogenic stimulus, had no significant effect. Inclusion of indomethacin (2.4 × 10-5 M) in the culture medium during enzymatic dissociation of endometrial scrapings and during subsequent culture of the dispersed cells for 4 days did not prevent the expression of the decidual reaction as judged by the appearance of polyploid and of multinucleated cells. In vivo administration of indomethacin (2 mg/rat ip) on day L3 or on day L4, 3 h before collecting the endometrial scrapings, reduced the incidence of polyploidy in the 4-day cultures. Th...

Calcium dependence of steroid and guanine 3',5'-monophosphate induction of germinal vesicle breakdown in Rana pipiens oocytes.

The action of progesterone in the induction of meiotic maturation in amphibian oocytes is thought to be dependent on the presence of exogenous Ca2+ and/or Mg2+ ions. In the present study we report that exogenous Ca2+ is essential only during the first 5–10 min after exposure of Rana pipiens oocytes to steroid and that there is no significant Mg2+ requirement for germinal vesicle (oocyte nucleus) breakdown (GVBD). The order of effectiveness of divalent cations is Ca > Sr > Ba > Mg. GVBD is inhibited by only about 30% if denuded oocytes are transferred from Ca-containing to Ca-free medium containing inducing levels of steroid. If the diffusible Ca2+ pool (t½ < 15 min) is diminished by preincubation in Ca-free, EDTA-containing medium, GVBD is inhibited by 70-80%. Preincubation in Ca-free medium at 0–4 C results in the loss of 55–60% of the denuded oocyte Ca2+ and complete inhibition of steroid-induced GVBD. Progesterone uptake was independent of [Ca2+]o. Progesterone stimulates net 45Ca2+ uptake by denuded o...

Progesterone and estradiol-17-β concentration in human endometrial carcinoma and the effect of progesterone on [ 3H]-thymidine incorporation

The estradiol-17-β and progesterone concentrations were determined in human endometrial adenocarcinomas obtained from 18 untreated and seven progesterone treated patients. The [ 3H]-thymidine incorporation was measured in 11 of the tumours. The mean tissue concentrations of the two steroids approximated those in normal proliferative endometria. However, the progesterone concentration differed markedly between different tumours. In untreated patients the concentration of the steroid hormones were neither correlated to each other nor to the clinical stage or to the degree of differentiation of the tumours. In progesterone treated patients well differentiated tumours had the best capacity for progesterone uptake. No difference in [ 3H]-thymidine incorporation could be demonstrated between 6 progesterone treated tumours and five tumours from untreated patients.

Estrogen concentrations and effect of estradiol on progesterone receptors in the fetal and new-born guinea-pigs

Estradiol concentration in plasma of fetal guinea-pigs, determined by radioimmunoassay, varies from 9 to 40 pg/ml and the concentration of estrone between 80 to 105 pg/ml. The concentrations of both estrogens do not change significantly during fetal evolution. The total number of specific estradiol binding sites in fetal guinea-pig uterus reaches 18 to 20pmol/mg DNA at the end of gestation, and the concentrations of estradiol plus estrone is ∼1500 pg per g of this tissue which correlates well with the number of specific binding sites occupied by the endogenous estrogens (2–4 pmol/mg DNA). In the fetal uterus, estradiol receptors appear at about mid-gestation (from 34 days) but progesterone receptors are detectable only after 50–52 days of gestation. After estradiol treatment of the pregnant guinea pig (1 mg/kg/day for 3 days), the following changes take place in the fetal uterus: (1) Induction of progesterone receptor protein at an earlier period (37–42 days) when this receptor is not detectable in control animals. (2) Five to ten-fold increase in progesterone receptors at the end of gestation. (3) An increase of [ 3H]-progesterone uptake by fetal uterus (localized by autoradiography). (4) The stimulation of progesterone receptors is of long duration. Five days after treatment the values are similar to those obtained 24 h after the administration of the last dose of estradiol. (5) Similar effects were noted also in fetal ovary, but not in lungs, kidney, brain and heart or placenta. (6) The induction of progesterone receptors by estradiol is significantly lower in the uterus of new-born guinea pigs (2–7 days old). It is concluded that estradiol expresses its biological effect in the fetal compartment, increasing the levels of progesterone receptors.

Half-Life of Plasma Progesterone in Turkey Layers and Non-Layers

Large White turkey layers and non-layers were used in this study of progesterone half-life. The half-life was determined from regression of linear decrease in plasma progesterone after a single injection of unlabelled progesterone. Blood samples were collected every 10 min for a period of 2 hr after hormone injection. Radioimmunoassay was used to measure progesterone in all plasma samples.The half-life of plasma progesterone in layers (63.7 ± 3.3 min.) was significantly lower than in non-layers (91.8 ± 6.0 min.). Our results indicated that progesterone synthesis or release in turkey layers could have been much greater than non-layers. This would also suggest that the uptake of progesterone by receptors in target tissues could be much more in layers than non-layers.

Characteristics of (3H) Estrogen and (3H) Progestin Uptake and Effects of Progesterone on (3H) Estrogen Uptake in Brain, Anterior Pituitary and Peripheral Tissues of Male and Female Guinea Pigs1

In Exp. 1, whole homogenate and nuclear fraction uptake patterns of radioactivity were measured in several tissues 1, 2 and 6 h after injection of (3H) estradiol-17β to gonadectomized male and female guinea pigs. In general, in both fractions the pattern of accumulated radioactivity was the same for males and females (uterus and sminal vesicle>anterior pituitary>hypothalamus cortex). However, a sex difference was noted in the time of peak estrogen uptake. The peak for females was at 1 h, whereas in males peak radioactivity in target tissues was observed at 2 h. Males and females showed equivalent levels of estrogen uptake in target tissues at 2 h but by 6 h levels in males began to decline, though not significantly, to a level lower than females. The results are consistent with a role for estrogen in central and peripheral tissues of male as well as female guinea pigs, and suggest a basis for the lesser sensitivity of males than females to estrogen on a variety of measures. Experiments 2 and 3 assessed whole homogenate and nuclear uptake of radioactivity in several tissues 15 min and 2 h after injection of (3H) progesterone to ovariectomized, estrogen-primed guinea pigs. Only uterus accumulated radioactivity in the nuclear fraction much above background. Negligible levels of radioactivity were accumulated in cell nuclei of anterior pituitary, hypothalamus, midbrain and cortex. Likewise, only uterine radioactivity was found to be saturable when animals were pretreated with an excess of unlabelled progesterone. The effect of progesterone pretreatment on whole homogenate and nuclear uptake of radioactivity 2 or 6 h after injection of (3H) estradiol-17β was examined in several tissues of ovariectomized guinea pigs either primed or not primed with unlabelled estradiol-17β. In no case was neural uptake of radioactivity affected by the progesterone pretreatment.

Progesterone in the uterus. VIII. Uptake of corticosterone and incorporation of progesterone under concurrent injection of corticosterone into rat uterus

A study of the subcellular distribution of radioactivity in rat uterus after injection of labelled corticosterone showed that the radioactivity was observed in all fractions from 5 min. to 120 min. A maximum uptake was observed 10 min. after application of the labelled steroid. Competitive uptake of radioactive progesterone and unlabelled corticosterone was assayed 10 min. after injection of the hormone mixture. The ratio between radioactive progesterone and unlabelled corticosterone was 1 : 1 and 1 : 2 (moles:moles), respectively. Compared with control experiments with rats which had received radioactive progesterone alone, the results gave evidence that progesterone found in all subcellular fractions and in the total homogenate was not depressed by unlabelled corticosterone. However, unlabelled progesterone reduced the tritiated progesterone in uterine tissue. This observation demonstrates that the uptake of progesterone by rat uterus is specific.

Exogenous hormone uptake and retention in the rat uterus at the time of ovo-implantation.

The uterine uptake of tritiated hormones, oestradiol and progesterone, was studied at the time of ovum implantation in the rat. Macromolecular dyes such as trypan blue were used to distinguish implanted sites from the unimplanted ones. A differential uptake was found between the implanted and unimplanted sites in normal 6th day pregnant females. Oestradiol was retained more at the unimplanted sites, whereas its half-life was approximately the same at the two levels. On the other hand progesterone was found in greater amounts in the implanted sites due to a difference in half-life for each site (30 min for unimplanted sites, 40 min for implanted ones during the first 30 min following injection). When endogenous oestradiol retention was suppressed by ovariectomy, higher uptake of [3H] oestradiol in unimplanted sites was not found. These results suggest a heterogeneity in the binding sites of oestradiol in the pregnant uterus.

An autoradiographic study of sex steroids in the chicken telencephalon

The uptake and incorporation of oestrogen, progesterone, and testosterone in the chicken telencephalon were studied by autoradiography. All three hormones labelled cells in the hyperstriatum ventrale, and the general distribution was similar with each hormone. However, the distribution was more extensive with oestrogen and testosterone than with progesterone which was confined to a small area of the lateral hyperstriatum. Testosterone and oestrogen also labelled cells in the hyperstriatum dorsale and in the nucleus intercalatus hyperstriaticus.

Progesterone in the uterus. VII. Uptake of cortisol and incorporation of progesterone under simultaneous application of cortisol into rat uterus

After injection of radioactively labelled Cortisol, the distribution of the radioactivity in the subcellular fractions of the rat uterus (nuclei, mitochondria, microsomes and 105 000 × g supernatant) was studied. In all fractions, radioactivity was observed and maxima were found 10, 20 and 50 min. after injection of the labelled hormone. Radioactivity was measured in all subcellular fractions even 180 min. after application of labelled cortisol. Additionally, radiolabelled progesterone and unlabelled cortisol in the ratio 1:1 or 1:2 (moles:moles) were injected into the animals. Studying the uptake of labelled progesterone in the subcellular fractions of the uterine tissue, revealed that no competition of unlabelled cortisol could be observed 10, 20 and 50 min. after application of the hormone mixture, compared with the control experiments. The results of this study give evidence that the progesterone uptake into rat uterus is specific and cannot be influenced by unlabelled cortisol.

Binding of progesterone receptor by nuclear preparations of rabbit and guinea pig uterus.

Guinea pig and rabbit uterine nuclei bound [3H] progesterone in vitro only in the presence of cytosol from estrogen-stimulated uteri. Nuclei from unstimulated and estrogen-stimulated uteri bound progesterone equally well. Nuclei of nontarget tissues also bound progesterone, but to a lesser extent. The rate of nuclear bindins increased with temperature from 0-30 degrees. At 25 degrees nuclear binding remained stable for at least 3 h, but at temperatures of 30 degrees and greater, nuclear binding decreased rapidly after 15 min. Activation of the progesterone-cytoplasmic receptor complex (the change in the complex that enables it to bind quickly to nuclei at 0 degrees) took place slowly at temperatures from 0-5 degrees and rapidly at 10-25 degrees. Activation was facilitated by dilution of the cytosol. Some activation occurred in diluted cytosol in the absence of added progesterone. The cytoplasmic progesterone receptor had a sedimentation coefficient of 7 S when concentrated cytosol (20 mg of protein/ml) was incubated with progesterone at 0 degrees in 5 mM phosphate buffer. Diluting the cytosol and increasing the temperature to 20 degrees caused the sedimentation coefficient to decrease to 5.5 S. Gel filtration of guinea pig uterine cytosol on Sephadex G-100, in the absence of progesterone, yielded a progesterone-binding fraction in the void volume, with a sedimentation coefficient of 5.5 S. The complex of progesterone with the material in the void volume was taken up by nuclei at 0 degrees more rapidly than the complex of progesterone and crude cytosol. The nuclear uptake of progesterone was decreased in phosphate buffer of concentrations greater than 80 mM. Under conditions that favor the nuclear binding of progesterone, the sedimentation coefficient of the cytoplasmic progesterone receptor was 5.5 S. This may be the form of the preceptor which is taken up by nuclei. In decreasing order of effectiveness, unlabeled progesterone, 5 alpha-pregnane-3,20-dione, corticosterone 20 alpha-hydroxy-4-pregnen-3-one, testosterone, estradiol-17 beta, and cortisol competed with [3H] progesterone for binding to nuclei.

The head extractions, brain and pituitary uptake and metabolism of progesterone and 5α-dihydroprogesterone in anesthetized, female rabbits

Three days after ovariectomy adult female rabbits were injected intramuscularly with either 2 μg estradiol/kg b.w., 0.5 mg progesterone/kg b.w., 2 μg estradiol plus 0.5 mg progesterone/kg b.w., or oil vehicle daily for 5 days. On the sixth day the animals were anesthetized and given a continuous infusion of [ 14C]progesterone and [ 3H]5α-pregnane-3,20-dione (5α-DHP) for 4 h via the femoral vein. Head extractions, calculated from the difference in blood concentrations of radioactive steroids between the femoral artery and jugular vein, were in the range of 60–75% for both progesterone and 5α-DHP and were unaffected by the hormone treatments. Nine brain areas and the pituitary were analyzed for [ 14C]progesterone, [ 3H]5α-DHP and [ 14C]5α-DHP. Generally, the brain and pituitary retention and distribution of [ 14C]progesterone and [ 3H]5α-DHP and the brain and pituitary metabolism of [ 14C]progesterone were unaffected by hormone treatments. In the cerebellum, progesterone treatment increased [ 14C]progesterone retention as compared to oil treatment. All tissues contained 2–7 times more [ 14C]progesterone than arterial blood concentrations. [ 3H]5α-DHP tissue: arterial blood concentrations ratios were much lower ranging from 0.9 to 1.78. [ 14C]progesterone and [ 3H]5α-DHP showed similar brain distribution with highest concentrations in the pons, pons reticulum and midbrain reticulum. All tissues converted progesterone to 5α-DHP, but only the cerebellum contained more [ 14C]5α-DHP than [ 14C]progesterone.

Effect of centchroman on the uptake of tritiated estradiol-17β and progesterone by different tissues of ovariectomized rats

The effects of centchroman on the uptake of 6,7- 3H-estradiol and 1,2,6,7- 3H-progesterone by different tissues in ovariectomized young adult rats were studied. Pre-treatment with centchroman inhibited the uptake of radioactive estradiol by the hypothalamus pituitary, uterus, fallopian tube, adrenal and liver, but not that by plasma. In the other set of experimental animals, centchroman also counteracted the estradiol benzoate-induced increase in the weight of the pituitary, uterus and vagina, although administration of centchroman alone increased the weight of the pituitary and uterus in ovariectomized rats. These results may be explained on the basis of competitive inhibition of estrogen at target tissue level. Compared to the control group, the uptake of radioactivity as pure progesterone was more in all the tissues except the vagina and liver of the animals pre-treated with centchroman, whereas the uptake of total radioactivity was increased in the liver and plasma but remained unchanged in other tissues. The results indicate that centchroman, which has been claimed to have an anti-progestational action, did not accelerate the metabolism or elimination of progesterone, nor did it interfere with the uptake of progesterone by the target tissue.

Pentobarbital inhibition of progesterone-induced behavioral estrus in ovariectomized guinea pigs

Administration of pentobarbital inhibits the facilitatory effects of progesterone on the release of gonadotropins. In this experiment facilitatory effects of progesterone on lordosis behavior in guinea pigs were examined with pentobarbital anesthesia. Two major animal groups were subjects: one was short-term ovariectomized (2 weeks) and the other was long-term ovariectomized (several months). All animals received estradiol benzoate (6.6 mug s.c.) followed by progesterone (0.4 mg s.c.) 40 h later. Lordosis behavior was induced by the manual stimulation method of Young et al.29 Sodium pentobarbital (30 mg/kg) was injected 8,4 or 2 h before, simultaneously or 1, 2, 6, or 7 h after progesterone. Animals which received pentobarbital slept for 4.5-5 h with subsequent drowsiness for an additional 0.5-1 h. Pentobarbital injections given 8 h before progesterone had no effect on latency to the first lordosis or on other parameters of estrous behavior. However, pentobarbital delayed the onset of heat in estrogen treated ovariectomized guinea pigs when given 4 h before, 2 h before, or simultaneously with progesterone. The delay was directly related to the length of time the animals remained asleep after the progesterone injection, since estrous behavior was invariably displayed with the latency of controls after the animal awoke. Moreover, in animals which were awake for 1-2 h immediately after the progesterone injection before receiving pentobarbital, the latency of recovery from anesthesia to the first display of lordosis was about 1-1.5 h shorter than in the other pentobarbital groups. In contrast to the latency effects of pentobarbital, the duration of heat was unaffected by the anesthetic for all groups mentioned. In animals which received pentobarbital after they were already in heat, pentobarbital injection terminated heat and abolished it completely, since lordosis behavior was not displayed in the hours after recovery from anesthesia. Gross hypothalamic uptake of progesterone was not influenced by pentobarbital administration. Thus, it is tentatively concluded that an incubation period is necessary for progesterone to mediate the display of estrous behavior in the guinea pig in addition to the time necessary for neural uptake. The way in which pentobarbital interferes with the period of progesterone incubation is not currently known.

Metabolic clearance rate, production rate, and mammary uptake and metabolism of progesterone in cows

Metabolic clearance rate, production rate, and mammary uptake and metabolism of progesterone in cows

Effect of intrauterine t-device and copper-t on in vitro uptake of estradiol-17β-6, 7- 3H and progesterone-1, 2- 3H in monkey uterus and cervix

The uptake of estradiol-17β-6, 7- 3H and progesterone-1, 2- 3H in the uterus and cervix was investigated by an in vitro method after intrauterine insertion of the copper-T and plain-T in monkeys. The estrogen uptake in the uterus of the plain-T device inserted monkeys showed an increase as compared to that of the copper-T inserted animals and the intact control group (where the T device was not used). Estrogen uptake in the copper-T and intact control animals did not show any significant difference. The progesterone uptake was increased in intact control monkeys as compared to that of the copper-T and plain-T inserted monkeys. The estrogen and progesterone uptake in the cervix was similar to that observed in the uterus. It appears that the mechanism of action of the copper-T may be different from that of the plain-T.