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Progesterone Production (progesterone + production)
Selected AbstractsLuteal Characteristics and Progesterone Production on Day 5 of the Bovine Oestrous CycleREPRODUCTION IN DOMESTIC ANIMALS, Issue 6 2007MP Green Contents In this study we have examined luteal function in non-lactating and late lactation dairy cows on day 5 of the cycle, during the period of the post-ovulatory progesterone rise. Comparison of luteal progesterone content and in vitro synthetic capacity with circulating plasma progesterone demonstrated that circulating progesterone concentration is a function of total luteal activity rather than the activity of individual units of tissue. Incubation of luteal tissue in vitro demonstrated stimulatory activity of LH and IGF-I, and to a greater degree IGF-II, on luteal progesterone synthesis. Finally the study showed no effect of double ovulation on luteal function. Occurrence of double ovulation in 35% of animals was not associated with any difference in luteal function or plasma progesterone concentrations. [source] Simulated conditions of microgravity increases progesterone production in I-10 cells of Leydig tumor cell lineINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2008Tomoyoshi Kaneko Background: The prospect of long-term residence in outer space is becoming a reality. Previously we found that testosterone secretion and spermatogenesis is reduced in model mice on which the shift of body fluids in space is simulated. The present study examines the effects of the microgravity (,G) environment on steroidogenesis of Leydig cells. Methods: I-10 cells were cultured for 24 h under a simulated ,G environment. Progesterone production was evaluated as steroidogenesis. Western blots of the enzyme, 3,hydroxy dehydrogenase (HSD) as well as of the transcription factors, Ad4bp/SF-1 and DAX-1, the amount of adenosine3,,5,-cyclic monophosphate (cAMP) and cell morphology were investigated. The ,G environment was simulated using clinostat rotation (CR). Rotational (Cont-1) and stationary (Cont-2) controls always received a regular gravity effect with and without rotatory motion, respectively. Results: Progesterone levels in cells under CR were significantly increased compared with those of both controls. Increased progesterone production was not related to the expression of either of the transcription factors or the enzyme. Although the cytoplasm expanded, the amount of cAMP produced under CR did not significantly differ from that produced under both control environments. Conclusions: Our findings showed that I-10 cells produced more progesterone under a ,G, than under control environments. Since the amounts of 3,HSD, Ad4bp/SF-1, DAX-1 and cAMP were not altered, the increase in steroid production under CR might be due to the expansion of cytoplasm, where steroidogenesis occurs. Steroidogenesis should be investigated in more detail to predict the effects of outer space on humans. [source] Metals in human placenta: focus on the effects of cadmium on steroid hormones and leptin,JOURNAL OF APPLIED TOXICOLOGY, Issue 3 2010Sandra Stasenko Abstract Cadmium and other metallic ions can act as metalloestrogens and endocrine disruptors of reproductive tissues and fetal development in mammals, including humans. The detrimental effects occur with respect to the synthesis of both steroid and polypeptide hormones in the placenta. Leptin is produced by the trophoblast and may regulate fetal organogenesis and development. In human term placentas, concentrations of toxic metals and their effects on steroidogenesis were assessed in healthy parturients (109 non-smokers and 99 smokers) in relation to tobacco smoking. Trace elements (cadmium, lead, iron, zinc and copper) were analyzed in placentas using atomic absorption spectroscopy, and steroid hormones (progesterone and estradiol) were assayed in placental samples by an enzyme-immunometric method. Cadmium concentrations were doubled in placentas of smokers as compared with non-smokers, and placental lead and zinc concentrations increased significantly. Placental concentrations of iron, copper, progesterone and estradiol did not differ. In addition, human trophoblast cells were co-cultured with 0, 5, 10 or 20,,µm CdCl2 for 96,,h and leptin mRNA assessed by quantitative polymerase chain reaction. Leptin mRNA declined dose-responsively as a result of CdCl2 exposure. Collectively, the results confirm that human placental tissue offers a unique opportunity to biomonitor cadmium exposure in both the maternal and the internal fetal environments. In addition, the results strongly suggest that cadmium may cause a decline in placental leptin synthesis, as we have previously shown for placental progesterone production. This may constitute further evidence of the endocrine-disrupting effects of cadmium, as a constituent of tobacco smoke, on reproduction in women. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of FSH and LH on Steroid Production by Buffalo (Bubalus bubalis) Granulosa Cells Cultured In Vitro Under Serum-Free ConditionsREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2010M Shanmugam Contents The objective of this study was to examine the effects of FSH and LH on oestradiol-17, and progesterone production by buffalo granulosa cells cultured under serum-free conditions. Granulosa cells (3 × 105) from small (,5 mm diameter) follicles were cultured for up to 4 days in 48-well plates coated with 3.3 ,g/cm2 fibronectin in Dulbecco's modified Eagle's medium (DMEM) : nutrient mixture F-12 Ham (1 : 1 ratio) supplemented with 10,7 m androstenedione, 5 ,g/ml human apo-transferrin and 0.1% bovine serum albumin, in the presence or absence of FSH or LH (0, 1, 2, 4, 8, 16, 32 or 64 ng/ml each). Basal oestradiol-17, production by granulosa cells from small follicles reduced (p < 0.01) from days 1 to 2 of culture and became undetectable by day 3 and basal progesterone production increased (p < 0.05) from day 1 through day 4 of the culture. Although there was no effect of FSH on day 1 of the culture, FSH at 2, 4, 8 and 16 ng/ml increased (p < 0.05) oestradiol-17, production by granulosa cells from small follicles on day 2. Progesterone secretion was increased (p < 0.05) by all doses of FSH on all days of culture. All doses of LH had no effect on oestradiol-17, or progesterone production by granulosa cells from small follicles on any day of the culture. The results of this study demonstrate a serum-free culture system for buffalo granulosa cells and stimulatory effect of FSH but not LH on steroid hormone production by buffalo granulosa cells under these conditions. [source] Luteal Deficiency and Embryo Mortality in the MareREPRODUCTION IN DOMESTIC ANIMALS, Issue 3-4 2001WR Allen Four separate components combine to produce the progesterone and biologically active 5,-reduced pregnanes needed to maintain pregnancy in the mare. The primary corpus luteum (CL) is prolonged beyond its cyclical lifespan by the down-regulation of endometrial oxytocin receptors to prevent activation of the luteolytic pathway and its waning progesterone production is supplemented from day 40 of gestation by the formation of a series of accessory CL which develop in the maternal ovaries as a result of the gonadotrophic actions of pituitary FSH and the equine chorionic gonadotrophin (eCG). From around day 100 the allantochorion secretes progesterone and progestagens directly to the endometrium and underlying myometrium and, in the last month of gestation, the enlarging foetal adrenal gland secretes appreciable quantities of pregnenelone which is also utilized by the placenta to synthesize progestagens. Between 10 and 15% of mares undergo foetal death and abortion at some time in gestation and the majority of these losses occur during the first 40 days of gestation when the primary CL is the sole source of progesterone. Yet, all the available evidence suggests that untoward luteolysis is not common in this period and the losses that do occur have other underlying causes. Beyond day 40 the secondary CL receive powerful luteotrophic support from eCG and from day 80,100 until term the supply organ (placenta) and target tissues (endometrium and myometrium) are in direct contact with each other over their entire surface. In the face of this interlocking and failsafe system for progestagen production throughout pregnancy, and despite a paucity of evidence that a deficiency of progesterone production is a cause of pregnancy loss in the mare, it is surprising, and worrying, that annually many thousands of pregnant mares throughout the world are given exogenous progestagen therapy during part or all of their gestation as a form of preventative insurance against the possibility of pregnancy failure. Basic investigative research is required urgently to validate or debunk the practice. [source] Nitric oxide in bovine corpus luteum: Possible mechanisms of action in luteolysisANIMAL SCIENCE JOURNAL, Issue 3 2007Anna KORZEKWA ABSTRACT Although prostaglandin (PG) F2, is considered as the principal luteolytic factor, its action on the bovine corpus luteum (CL) is mediated by other intraovarian factors. Among them, nitric oxide (NO) seems to play a mandatory role in luteolysis. In this article we review the background and current status of work on possible roles of NO in the CL function, based on available information and our own experimental data. NO is produced in all three main types of bovine CL cells: steroidogenic, endothelial and immune cells. PGF2, and some luteolytic cytokines (tumor necrosis factor, interferon) increase NO production and stimulate NO synthase expression in the bovine CL. NO inhibits progesterone production, stimulates the secretion of PGF2, and leukotriene C4, reduces the number of viable luteal cells and, finally, participates in functional luteolysis. NO induces the apoptotic death of CL cells by the modulation of bcl-2 family gene expression and the stimulation of caspase-3 gene expression and activity. However, this simple molecule shows both luteolytic and luteotropic actions during the estrous cycle in ruminants. The aim of this overview is to present and discuss the recent findings crucial for understanding NO role in the process of CL regression in cattle. [source] Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolismAUSTRALIAN VETERINARY JOURNAL, Issue 10 2001AR RABIEE Objective To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. Methods Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2a) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20a-OH and 20b-OH) were monitored for a period of 5 weeks. Results Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). Conclusions These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4. [source] | ||||||||||