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Query: DrugBank:APRD00627 (MAP)
 15,705 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Progesterone reinitiates meiotic maturation in Xenopus oocytes. Evidence is reported which indicates that the steroid acts at the level of the cell surface and suggests that an induced change of Ca2+ distribution triggers in turn a cascade of cytoplasmic events including protein synthesis and germinal vesicle (nucleus) breakdown. These novel features of steroid hormone action in amphibian oocytes are discussed in relation to presently accepted views of the mechanism of action of steroid hormones in somatic cells.
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PMID:Steroid-induced meiotic division in Xenopus laevis oocytes: surface and calcium. 3 46

A bone culture system was used to compare the effects of several hormones on the response of 5-day-old mouse calvaria to parathyroid hormone (PTH). The results showed that salmon calcitonin was almost 10-5 times more active than any other hormone in preventing the PTH-induced release of calcium and caused a dose-related inhibition of calcium release over a range of 0-2-200 milli MRC units/culture. A high dose of calcitonin (200 milli MRC units) caused a net accretion of calcium in the absence of PTH. Progesterone and testosterone were more active than the naturally occurring oestrogens although a synthetic oestrogen (stillboestrol diphosphate) had approximately the same potency. High concentrations of these hormones caused a net accretion of calcium whether or not PTH was present. Cortisol was only effective at high doses, as was the steroid precursor cholesterol. In the present culture system the thyroid hormones (triiodothyronine and thyroxine) inhibited the action of PTH. It was concluded that these agents acted in a similar fashion to the oestrogens. That is, they prevented the accumulation of citric acid induced by PTH by reducing the rate of glycolysis. None of the hormones affected the inhibition of citrate oxidation caused by PTH. The results also showed that, whilst these hormones inhibited PTH-mediated bone resorption, they had an action on bone independent of PTH. Experiments with clomiphene citrate failed to demonstrate an oestrogen receptor in bone.
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PMID:A comparison of the effects of the calcitonins, steroid hormones and thyroid hormones on the response of bone to parathyroid hormone in tissue culture. 16 33

The sublethal dose of calcium hypochlorite (CH) of 0.2--0.3 mg/ml active chlorine did not cause, after 5 min, morphological changes in the spores of Bacillus anthracoides which could be detected by phase contrast microscopy, or a decrease in the content of dipicolinic acid (DPA) in the spores. Further cultivation of the spores treated with the sublethal dose of CH om MPA resulted in a delay of changes which were typical of normal germination process (swelling, loss of light refraction, decrease in DPA content). The action of the lethal dose of CH (0.2--0.3 mg/ml active chlorine during 1.5 hr or 5.6 mg/ml active chlorine during 1 hr) causes a decrease in light refraction, changes in the dimensions of spores, and a decrease in the content of DPA in the spores by a factor of 4--5. A sharp decrease in the content of DPA in the spores may characterize not only their germination but also their death caused by lethal doses of the chlorine containing disinfectant.
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PMID:[Effect of calcium hypochlorite on Bacillus anthracoides spores]. 18 5

The maturation of the amphibian oocyte has been analyzed. Progesterone as well as organomercurials, lanthanum chloride and propranolol rapidly induce maturation. These chemicals are active only is applied on the cell surface. The mechanism seems to be an induction of the migration of Ca2+ from the cell membrane to the cytoplasm. K + may also play a role. Progesterone induced maturation involves synthesis of histone and histone kinase as well as several biologically active but chemically unidentified factors. cAMP does not seem to be directly involved, whereas protein phosphorylation is so.
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PMID:The hormonal induction of maturation in amphibian oocytes. 21 52

An enzymatic procedure for the isolation of metabolically active tumour cells from human renal cell carcinoma is described. The cells were suspended by a multistep incubation procedure of the tissue in the presence of collagenase (10 mg enzyme/g tumour wet weight) dissolved in a calcium-free buffer solution. About 90% of the isolated tumour cells were viable, as judged by routine trypan blue staining. Electron microscopic examination revealed tumour cells in various stages of dedifferentiation. The cells had retained their capability of protein synthesis. In short term experiments the effects of 17 beta-oestradiol and progesterone on the incorporation of [U - C] L-leucine into cellular proteins was studied; Progesterone was found to exhibit a slight tumour antianabolic or catabolic action. A 17 beta-oestradiol-dependent modulation of the rates of protein synthesis was not observed.
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PMID:[Viable cells from human renal cell carcinoma: isolation procedure and analysis of hormone sensitivity (author's transl)]. 22 52

The effect of progesterone and prostaglandin administration on the timing of farrowing was studied in three groups of 25 sows each. Progesterone treatment (100 mg/day) on days 112, 113 and 114 of gestation (group I) significantly prolonged the gestation length to 116.4 +/- 0.4 (mean +/- s.e.) days compared to the control sows (group III; 115.5 +/- 0.2; P less than 0.05). Administration of prostaglandin (200 micrograms Cloprostanol intramuscularly) on day 115 of gestation following progesterone treatment (group II) resulted in a gestation length of 116.0 +/- 0.1 days, with the sows farrowing 25.4 +/- 1.0 h after the prostaglandin injection. 80% of the sows farrowed between 0800 and 1700 h of day 116 of gestation. Plasma progesterone levels were maintained by the exogenous progesterone during treatment. At farrowing, higher levels of progesterone were observed in groups I and II compared to controls. Prostaglandin treatment did not significantly alter withdrawal of progesterone in progesterone treated sows, suggesting that the actions of exogenous prostaglandin is primarily on the myometrium and the cervix. Hormonal treatment in late pregnancy did not have any adverse effects on piglet viability and growth rate, or subsequent reproductive performances of sows. Lactation was initiated normally, and the concentrations of lactose, protein, fat, IgG, Na+, Ca2+ and K+ in colostrum and milk were similar in all groups during the first 5 days of lactation.
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PMID:Control of parturition in the sow using progesterone and prostaglandin. 54 54

Influx and efflux of 45Ca++ ions in Xenopus leavis isolated full-grown oocytes were measured. Calcium influx was from 0.5 to 1 pmole/oocyte/h. Progesterone, which induces maturation does not influence Ca++ fluxes while PCMB caused a significant increase of Ca++ influx during the course of PCMB (p-Cl-HgBzO-) induced maturation. Our results show that the presence of Ca++ is not necessary in extracellular medium for germinal vesicle breakdown (GVBD) induced by progesterone. In contrast, the kinetic and the percent of germinal vesicle breakdown observed when maturation was induced by PCMB depend on the extracellular Ca++ concentration in Ca-EGTA buffers.
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PMID:[Oocyte maturation in Xenopus laevis. Arguments in favor of the role of calcium ions]. 81 72

A uterine pouch was prepared surgically in ewes before mating to study the production and chemical composition of uterine secretions during pregnancy. Pregnancy was established in 6 sheep and in the first 55 days uterine fluid was present in small amounts (less than 5 ml), whereas between 109 days post coitum and 3 days post partum the volume ranged from 90 to 775 ml. The chemical composition of uterine fluid in pregnancy differed from that of plasma especially in respect of its high concentration of total calcium (up to 83.5 mM) and prostaglandin (PG) F-2a (up to 1500 ng/ml). Progesterone was implicated as an important endocrine factor since uterine fluid (188 ml) with a high concentration of total calcium (53-5 mM) and PGF-2a(235ng/ml) was recovered from a non-pregnant sheep treated with progesterone for 115 days.
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PMID:Production, chemical composition and prostaglandin F-2alpha content of uterine fluid in pregnant sheep. 96 37

When slices of ovine luteal tissue were perfused with medium containing luteinizing hormone (LH), the output of progesterone was increased significantly (P less than 0.01) in eleven of twelve experiments. However, addition of LH to the medium did not influence the luteal cell membrane potential. The addition of 47 mM potassium to the medium resulted in increased progesterone output (P less than 0.01) and depolarization of the luteal cell membrane within 2 min. Progesterone output decreased to approximate pretreatment levels within 2 min of the return to normal potassium levels in the perfusion medium. High levels of potassium further increased the output of progesterone from tissue stimulated with LH. Perfusion of the slices with sodium-free medium also resulted in increased (P less than 0.01) progesterone output within 2 min, which returned to pretreatment levels within 2 min after normal sodium levels were restored to the medium. Perfusion of the slices with sodium-free medium did not influence the membrane potential. Perfusion of the tissue with LH, 47 mM potassium, or sodium-free medium had no effect on progesterone output if the medium was calcium-free and/or contained 2 mM EGTA. These data suggested that the calcium ion plays an important role in mediating the steroidogenic response of ovine luteal tissue to LH. A second series of experiments was designed to ascertain if luteal cells were coupled electrically. Sixty-six pairs of luteal cells separated by 150-300 mum were penetrated with electrodes and the membrane potential of both cells was studied. One cell of each pair was hyperpolarized by passage of 0.4 nA current into the cell, but in no case was there an effect on the membrane potential of the other penetrated cell. Likewise, when five cells were injected iontophoretically with Procion Yellow there was no evidence of diffusion of the dye to adjacent cells. There was no evidence obtained in this study which suggested that ovine luteal cells were coupled electrically.
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PMID:Relationship between membrane potential and progesterone release in ovine corpora lutea. 97 87

1 The characteristics of renin-like activity in rat uterus were studied. The optimum temperature was 50 degrees C and optimum pH 4.0. Potassium (100 mM) enhanced this activity but sodium or calcium had no effect. 2 Uterine renin-like activity was unchanged 24 h after bilateral nephrectomy. 3 Renin-like activity in the uterus increased slowly from birth to 4 weeks of age and faster between the 4th and 8th week. 4 Ovariectomy caused a considerable fall in uterine renin-like activity. 5 The following factors, known to affect renin secretion in the kidney, i.e., hypovolaemia, sodium loading, adrenalectomy, administration of desoxycorticosterone acetate and injection of isoprenaline, had no effect on uterine renin-like activity. 6 Stilboestrol, an oestrogen, caused a significant increase of uterine renin-like activity. Progesterone and testosterone had no significant effect on this activity but blocked the increase caused by stilboestrol. 7 During pregnancy there was a small but significant fall of renin-like activity in the uterus in the first week and a continuous increase throughout the later period of pregnancy. 8 It is concluded that uterine renin-like activity is independent of kidney renin and does not respond to stimuli affecting kidney renin. Uterine renin activity is hormone-dependent and may be governed by the ratio, oestrogen : progesterone.
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PMID:Rat uterus renin-like activity: effect of stimuli and hormones. 126 Jan 72


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