A simple procedure for the isolation of rat kidney lysosomes

BACKGROUND

A procedure for the isolation of highly purified lysosomes from normal rat kidney is described.

METHODS

The method depends on the swelling of mitochondria when the postnuclear supernatant fraction is incubated with 2 mM Ca2+. The lysosomes can then be separated from the swollen mitochondria by Percoll density gradient centrifugation.

RESULTS

The lysosomal fraction obtained by our method was enriched more than 30-fold in terms of marker enzymes with a yield of about 11%. Electron microscopic examination and the measurement of the activities of marker enzymes for various subcellular organelles indicated that our lysosomal preparation was essentially free from contamination by other organelles.

CONCLUSION

We believe that this procedure for isolating kidney lysosome will be useful in the study of the mechanisms of specific modification, processing and catabolism of proteins.

Differential regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase in the rat corpus luteum: induction of manganese superoxide dismutase messenger ribonucleic acid by inflammatory cytokines

This study was undertaken to investigate the regulation of mitochondrial manganese superoxide dismutase (Mn-SOD) and cytosolic copper-zinc SOD (Cu,Zn-SOD) in the corpus luteum by inflammatory cytokines. We first examined the developmental expression of both SOD mRNAs in the rat corpus luteum throughout pregnancy. SOD mRNA levels were determined by semiquantitative reverse transcription-polymerase chain reaction. Whereas Cu,Zn-SOD mRNA levels decreased during late pregnancy, Mn-SOD mRNA levels remained elevated. We secondly examined the effects of inflammatory reaction on luteal SODs. Rats received injections of lipopolysaccharide (LPS; 5 mg, i.p.) on Day 15 of pregnancy, and corpora lutea were removed 2 h later. LPS caused an increase in Mn-SOD mRNA levels in the corpus luteum and a decrease in serum progesterone levels, but neither in levels of Cu,Zn-SOD mRNA. To further study the effects of LPS or LPS-induced cytokines, we incubated either whole corpora lutea obtained on Day 15 of pregnancy or a temperature-sensitive simian virus-40 transformed luteal cell line (GG-CL; derived from large luteal cells of the corpus luteum of pregnant rats) in serum-free medium with LPS, interleukin-1alpha (IL-1alpha), IL-beta, IL-6, and tumor necrosis factor alpha. LPS and these cytokines induced a remarkable increase in Mn-SOD mRNA levels in both corpora lutea and GG-CL cells but had no effect on Cu,Zn-SOD mRNA expression. In conclusion, Cu,Zn-SOD and Mn-SOD mRNAs are differently expressed and regulated in the corpus luteum of pregnancy. Mn-SOD mRNA, but not Cu,Zn-SOD mRNA, is highly induced by inflammatory cytokines and may play an important role in protecting luteal cells from inflammation-mediated oxidative damage.

Pinealectomy of melatonin implantation does not affect prolactin surge or luteal function in pseudopregnant rats

The effects of melatonin on twice daily surges in PRL and luteal function were studied in pseudopregnant (PSP) rats. Cyclic rats received pinealectomy or sham operation under pentobarbital anesthesia on diestrus 1. Pinealectomized rats immediately received a melatonin capsule (the PINX+Mel group) or a blank capsule (the PINX group), and sham group of rats received a blank capsule (the control group). After operation, all rats were maintained under the same photoperiod conditions (14L: 10D), and estrous cyclicity was examined. At the 8th estrous cycle after operation, PSP was induced by mechanical stimulation of the uterine cervix. The last day on which the rat exhibited the estrous smear was designated as day 1 of PSP. Blood samples were obtained by jugular venipuncture under light ether anesthesia between 1200 and 1300 h on days 1, 3, 5, 7, 9 and 11, and between 0000 and 0100 h on day 13 of PSP. All rats were decapitated between 1200 and 1300 h on day 13 of PSP, and trunk blood was collected. A silicon catheter was inserted into the right jugular vein under ether anesthesia on day 4 of PSP. Blood samplings were performed every 2 h between 1000 h on day 5 and 1000 h on day 6 of PSP. Serum concentrations of melatonin, PRL and progesterone were measured by radioimmunoassay. Pinealectomy or melatonin installation did not disturb the estrous cyclicity or the induction of PSP. There were no differences among the three groups of rats during PSP in the pattern or serum PRL concentrations, and there were no significant differences among these three groups in the serum progesterone concentration or weight of the corpus luteum. The present results indicated that the continuously high or low melatonin in the physiological range did not affect the rhythm or strength of PRL surges or luteal function in PSP rats.

Differential expression of the estrogen receptors alpha and beta in the rat corpus luteum of pregnancy: regulation by prolactin and placental lactogens

Estradiol, together with PRL and placental lactogens, regulates steroidogenesis and cell hypertrophy in the rat corpus luteum of pregnancy. Although binding experiments have demonstrated the presence of estrogen-binding sites, no evidence exists as to whether the rat corpus luteum of pregnancy expresses the estrogen receptor (ER) genes. In this investigation, we have analyzed the expression of the two ER genes (ER alpha and ER beta) (by RT-PCR and in situ hybridization) in the rat corpus luteum, studied their developmental changes throughout pregnancy, and investigated the regulation of ER alpha and ER beta messenger RNA (mRNA) expression by PRL and placental lactogens. The RT-PCR studies showed that both ER mRNA species (ER alpha and ER beta) are coexpressed in the rat corpus luteum during pregnancy. Whereas ER alpha mRNA increased from early pregnancy, reached a maximum at midpregnancy, and had a remarkable decline before parturition; ER beta mRNA remained constant throughout pregnancy, with a significant decline at parturition. Examination of ER alpha and ER beta mRNA expression at the cellular level, by in situ hybridization, showed ER alpha expressed in both follicles and corpus luteum, with maximal expression at midpregnancy. In parallel with the RT-PCR studies, ER beta mRNA was similarly expressed throughout pregnancy in the corpus luteum, but it was less abundant when compared with small and growing follicles. Western blot analysis revealed two ER immunoreactive proteins in the nuclear fraction obtained from pregnant rat corpus luteum: a 67-kDa moiety, highly expressed at midpregnancy but barely detectable in early and late gestation; and a 61-kDa form that remained developmentally unchanged. Hypophysectomy, performed early in pregnancy, induced a sharp decline in ER alpha mRNA expression but a less-marked reduction in ER beta mRNA levels. PRL treatment reverted the inhibition induced by hypophysectomy in both receptor subtypes. When primary luteinized cells were used to test the effect of PRL, rat placental lactogen I, and rat placental lactogen II on the expression of ER alpha and ER beta mRNA, all these lactogenic hormones stimulated both ER mRNA species in a dose-dependent manner. The regulation of ER mRNA expression was further evaluated in a luteal cell line, termed GG-CL, which apparently expresses only the ER beta mRNA species. Culture of the GG-CL cells, in the presence of PRL, resulted in a dose-related up-regulation of ER beta mRNA expression. In addition, PRL treatment enhanced the binding activity of GG-CL cell nuclear proteins to a classical estrogen response element. Furthermore, in these cells, estradiol treatment induced a dose-dependent up-regulation of the mRNA encoding protein kinase C delta isoform, a well-known estrogen target gene in the corpus luteum of the pregnant rat.

Establishment and characterization of a simian virus 40-transformed temperature-sensitive rat luteal cell line

The primary culture of rat luteal cells and their long-term maintenance have been difficult. Low cellular yields have limited the possibility for the study of gene regulation in luteal cells. The goal of this study was to develop a cell line to serve as a model by which to study the expression and regulation of various genes specific to luteal cells. We attempted to develop a luteal cell line by transformation of large luteal cells through infection with a temperature-sensitive simian virus (SV-40 tsA209) mutant that has a temperature-sensitive mutation required for the maintenance of cell transformation. We report here the successful establishment of such a cell line, designated GG-CL cells. Large luteal cells were purified to homogeneity by flow cytometry from corpora lutea of day 14 pregnant rats, cultured for 24 h, and then infected with the SV-40 tsA209 mutant virus. Transformed cells were maintained at the permissive temperature (33 C) until colonies were identified. Several colonies of transformed cells were isolated and passaged. They multiplied at 33 C and formed multilayers. At the nonpermissive temperature (40 C), cells reverted to the normal differentiated phenotype similar to the primary luteal cells in culture. To determine whether GG-CL cells express the genes found in normal luteal cells, messenger RNA (mRNA) expression was examined by either Northern analysis or RT-PCR with primers specific to each mRNA. GG-CL cells were found to express receptors for interleukin-6 and glucocorticoid, as well as the newly discovered estrogen receptor-beta (ER-beta) and the orphan nuclear receptor nur 77. No receptors for ER-alpha, progesterone, LH, or PRL could be detected. This cell line also expressed 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), but not cholesterol side-chain cleavage cytochrome P450 (P450scc), 3beta-hydroxysteroid dehydrogenase, or aromatase cytochrome P450 (P450arom). Although the cells did not express the PRL receptor, they did express Janus kinase (JAK2) and signal transducers and activators of transcription (Stat5b), and, when transfected with the PRL receptor, they responded to PRL with a marked inhibition in 20alpha-HSD mRNA expression. In addition, estradiol enhanced ER-beta expression in a dose-dependent manner whereas cAMP stimulation caused a marked and rapid increase in the expression of the orphan receptor nur 77. In summary, a temperature-sensitive cell line was successfully established from the large luteal cells of rat corpora lutea. These cells express key genes encoding enzymes and receptors inherent to this defined luteal cell population and respond to stimulation by PRL, estradiol, and cAMP.

Role of interleukin-1beta in superovulation in rats

In this study, the changes in interleukin-1beta (IL-1beta) mRNA expression and its localization in the ovary were studied in pregnant mares' serum gonadotropin (PMSG)-human CG (hCG) injected immature rats. Moreover, to study the in vivo role of IL-1 during ovulation, the IL-1 receptor antagonist (IL-1ra) was injected into the bilateral bursae (100 microg/15 microl/bursa) immediately or at the 3rd, 5th, 10th h after hCG injection. IL-1beta mRNA expression in the ovary had significantly (P<0.05) increased at the 6th h after hCG injection, and its level depended on the time interval between PMSG and hCG injections; the maximal IL-1beta mRNA expression was observed when hCG was injected 48 h after the PMSG injection. The signals of IL-1beta mRNA localized in the thecal layer, particularly in the large preovulatory follicles. Intrabursal IL-1ra injection at the 3rd h after hCG injection showed a trend toward lowering the number of ova shed, and the injection at the 5th h significantly (P<0.01) decreased the number of ova shed compared with the saline injected control group. At the 24th h after hCG injection, there were a few large preovulatory follicles with distinguishable theca and granulosa layers in the IL-1ra treated ovary, although these two layers were indistinguishable in the control ovary. These results indicated that IL-1beta mRNA expression was definitely induced by hCG stimulation, and, moreover, this expression was dependent on the stage of follicular maturation. IL-1 may be important for the ovulation in the superovulatory cycle by PMSG in rats.

IGF-I/IGFBP-1 as an index for discrimination between responder and nonresponder to recombinant human growth hormone in malnourished uremic patients on hemodialysis

From a clinical aspect, there are still a number of unsolved problems in patients with end-stage renal disease, for instance intractable malnutrition. The present study was undertaken to establish the therapeutic effect of recombinant human growth hormone (r-hGH) on the nutritional state and clarify the usefulness of the insulin-like growth factor-I (IGF-I) insulin-like growth factor binding protein-1 (IGFBP-1) ratio as nutritional indices for prediction of the clinical response in uremic patients on hemodialysis. Thirty hemodialysis patients (13 females and 17 males, mean age 56.7 +/- 15.2 years) were studied who were suffering from malnutrition and could not be treated by any of the usual nutritional therapies; they were subjected to 0.5 IU/kg/week of r-hGH subcutaneously after hemodialysis for 2 weeks. Blood samples were collected for measurement of the following plasma biochemical and hematological indices: serum IGF-I, IGFBP-1, growth hormone, total protein (TP), prealbumin, transferrin, albumin, serum urea nitrogen (SUN), creatinine, hematocrit, and amino acids. Immediately after r-hGH administration, SUN, essential amino acid and nonessential amino acid changed from 67.7 +/- 12.3 to 56.5 +/- 10.5 mg/dl (p < 0.05), from 798 +/- 84 to 1,115 +/- 208 microM/l (p < 0.05 vs. baseline), and from 2,185 +/- 221 to 2,814 +/- 621 microM/l (p < 0.05), respectively. Serum IGF-I increased markedly from 193 +/- 49 to 321 +/- 81 ng/ml, whereas serum IGFBP-1 decreased from 139 +/- 13 to 81 +/- 19 micrograms/l (p < 0.05). Four weeks after r-hGH administration, serum TP and albumin increased from 5.5 +/- 0.2 to 6.0 +/- 0.3 g/dl (p < 0.05) and from 3.2 +/- 0.2 to 3.6 +/- 0.3 g/dl (p < 0.05), respectively. Serum IGF-I/IGFBP-1 ratio was significantly higher in patients with an increase of 0.5 g/dl or more in serum albumin than in other patients with poor response and the control group before r-hGH administration. Patients with marked improvement in serum albumin showed an IGF-I/IGFBP-1 ratio of 2 or less. On the other hand, patients without favorable improvement in serum albumin had a higher ratio of 4 or more. We conclude that r-hGH and IGF-I improve the malnutritional state by alleviating hypoproteinemia and abnormality of serum amino acid profile in uremic patients on hemodialysis. In addition, the serum IGF-I/IGFBP-1 ratio is useful not only as a nutritional parameter but also as a predicting index of responsiveness to r-hGH.

Progesterone inhibits 20alpha-hydroxysteroid dehydrogenase expression in the rat corpus luteum through the glucocorticoid receptor

In this study, we investigated whether progesterone exerts an intraluteal action despite the lack of progesterone receptors (PR) in the rat corpus luteum and whether progesterone acts through the glucocorticoid receptor (GR) to enhance its own levels by down-regulating the expression of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). We first established that the corpus luteum constitutively expresses the GR throughout pregnancy and after parturition. We also generated a temperature sensitive SV-40 transformed luteal cell line (GG-CL) that expresses the GR and 20alpha-HSD but lacks the PR. Treatment with different doses of either progesterone or dexamethasone caused a dose-related decrease in 20alpha-HSD mRNA in both cultured corpora lutea and in the luteal cell line. RU486, a PR/GR antagonist, completely blocked both the progesterone and the dexamethasone mediated inhibition of 20alpha-HSD expression in GG-CL cells. In summary, this report provides the first evidence that despite the absence of the PR in the rat corpus luteum, progesterone can act through the GR to down-regulate the expression of 20alpha-HSD, an enzyme that catabolizes progesterone and reduces progesterone secretion by the corpus luteum.

Effect of varying amino acid levels on protein metabolism in nephrotic rats during total parenteral nutrition

In an attempt to determine appropriate diet in nephrotic syndrome, nephrotic rats, induced by puromycin aminonucleoside, were nourished by total parenteral nutrition fluid containing the same energy, but three different levels (1.65, 3.3, and 6.6%) of amino acids for 7 d. The fractional rate of total protein synthesis in the liver was determined by injecting a flooding dose of [3H]phenylalanine. The proportion of newly synthesized proteins retained and exported by the liver was estimated by injecting a tracer dose of [14C]leucine and then measuring the protein radioactivity remaining in the liver and present in the plasma after secretion was completed. Nephrotic animals synthesized more protein than control animals. Although the absolute synthesis rates of total protein in liver were increased with increasing amino acid administration, the absolute rates of synthesis of albumin were higher in the 3.3% group than in the other groups in nephrotic rats. However, kidney protein synthesis in nephrotic rats was higher in the 1.65% group than in the 3.3% group. Interestingly, the 3.3% group revealed the smallest urinary excretion of total protein and albumin. In addition, in the 3.3% group, plasma concentrations of total protein and albumin were higher, and plasma concentrations of total cholesterol and triglyceride were lower than in other groups. It was concluded that the 3.3% group, corresponding to a normal protein diet, has the greatest salutary effect on urinary protein excretion, followed by protein and lipid metabolism, in nephrotic rats. Not only protein intake but also the energy:protein ratio are important for diet therapy in nephrotic animals. The technique of total parenteral nutrition may be useful in defining the factors involved in glomerular permeability or permselectivity and intracellular protein metabolism.

Roles of reactive oxygen species in the regulation of luteal function

Ephemerality and prolongation of luteal function have been matters of great concern in reproduction for many years. However, their control mechanisms are very complex and differ among mammals. Recently, evidence has indicated that reactive oxygen species may play important roles in the regulation of luteal function. Reactive oxygen species are present in most somatic cells and are involved in apoptosis, or 'physiological cell death'. In the corpus luteum, reactive oxygen species also exert luteolytic effects as well as some paradoxical luteotrophic effects. This paper discusses the possible roles of reactive oxygen species in the control of luteal function.

Effects of clomiphene citrate on the endometrial thickness and echogenic pattern of the endometrium

OBJECTIVE

To study the effects of clomiphene citrate (CC) on the endometrium by ultrasound and to reveal the echogenic difference between the control cycle and the CC cycle.

DESIGN

Retrospective study of patients before and during a CC treatment.

SETTING

Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.

PATIENT(S)

Seventy-nine infertile women who had a spontaneous ovulation and a normal luteal function.

INTERVENTION(S)

Patients received 50 mg/d CC between days 5 and 9 of the menstrual cycle.

MAIN OUTCOME MEASURE(S)

Endometrial thickness, echogenic pattern of the endometrium, serum E2 content, and E2 and P receptor contents in the endometrium.

RESULT(S)

Endometrial thickness was significantly thinner during the CC cycle (7.6 +/- 1.4 mm, mean +/- SD, n = 79) than during the control cycle (8.5 +/- 1.7 mm, n = 79) on late proliferative days, but there was no significant difference on midsecretory days (10.8 +/- 2.2 mm during the CC cycle, n = 79; 11.2 +/- 2.2 mm during the control cycle, n = 79). The echogenic patterns, however, were different between the two cycles on midsecretory days. Moreover, the incidence in which patients showed a grade 3 endometrium on midsecretory days was significantly higher during the conceived CC cycle compared with the not-conceived CC cycle. Serum E2 levels were significantly higher, but E2 receptor contents in the endometrium were significantly lower during the CC cycle (67 +/- 46 fmol/mg, n = 13) compared with the control cycle (123 +/- 89 fmol/mg, n = 15) on late proliferative days.

CONCLUSION(S)

Clomiphene citrate affected the echogenic pattern of the endometrium, and most of the endometrium showed a grade 3 pattern on midsecretory days during the conceived CC cycle. Under the CC treatment, the comfortable endometrium for embryos might be different from the control cycle.

Therapeutic effect of a newly developed antioxidative agent (OPC-15161) on experimental immune complex nephritis

The effect of a newly developed free radical scavenger (OPC-15161) on the progression of nephrotoxic serum (NTS) nephritis was evaluated. NTS nephritis rats were sacrificed immediately before and 1, 2, 3, 6, and 24 h and 13 and 19 days after intravenous injection of NTS. The tissue content of phosphatidylcholine hydroperoxide, the activity of superoxide, the activity of superoxide dismutase in the renal cortex, and the serum malondialdehyde levels were measured. The phosphatidylcholine hydroperoxide content in the renal cortex of OPC-15161-treated NTS nephritis rats was lower than that in the control rats 24 h after NTS injection. The activity of superoxide dismutase in OPC-15161-treated rats was sustained in contrast to the decrease in this activity in the control rats 6 h after injection of NTS. The effects of OPC-15161, dipyridamole, and prednisolone on NTS nephritis rats were investigated. OPC-15161 (20 mg/kg p.o.) showed a potent inhibitory effect on the urinary protein excretion, whereas dipyridamole (30 and 100 mg/kg p.o.) and prednisolone (2 mg/kg p.o.) had less suppressive effects. In view of these results, we conclude that OPC-15161 notably ameliorated the urinary protein excretion by way of the suppression of lipid peroxidation in the renal tissue of NTS nephritis rats.

Nitric oxide concentrations in the follicular fluid and apoptosis of granulosa cells in human follicles

To study the relationship between follicular atresia, apoptosis, and nitric oxide (NO) generation in follicular development, steroidogenesis, NO levels in follicular fluid and apoptosis were analysed in the various sized follicles of women receiving ovarian stimulation with human menopausal gonadotrophin (HMG)-human chorionic gonadotrophin (HCG) treatments for in-vitro fertilization (IVF)-embryo transfer. The follicles were divided into three groups by diameter: large follicle, > or = 18 mm; medium follicle, > or = 12 and < or = 15 mm; small follicle, < or = 10 mm. Follicular fluid was obtained from 20 women 34 h after HCG administration, and the concentrations of oestradiol, progesterone and testosterone, and nitrite, nitrate, arginine and citrulline were measured. Granulosa cells obtained from each group of follicular fluid were stained with Hoechst dye, and nuclear morphology was examined by a fluorescence microscopy. Oestradiol and progesterone concentrations in large follicles were significantly (P < 0.01) higher than those in medium or small follicles, and testosterone concentrations in small follicles were significantly (P < 0.01) higher than those in large follicles. There were no significant differences in the concentrations of nitrite, nitrate, arginine and citrulline among three groups. The percentage of apoptotic cells with nuclear fragmentation was significantly (P < 0.01) higher in small follicles than in large follicles. The present results suggested that small follicles with poor response to HMG may undergo atresia through apoptosis. No significant difference in the follicular NO level between large and small follicles led us to speculate on a different responsiveness to NO in these two types of follicles.

[Effects of prostaglandin E1 on transient forebrain ischemia, especially in hippocampal CA 1 regions of the gerbil]

The effects of prostaglandin E1 (PGE1) on transient forebrain ischemia were studied in the gerbil. The animals were randomly divided into six groups of 6 each according to the method of administration as follows: group 1, no administration; group 2, subcutaneous administration with 5 ml.kg-1 of physiological saline, 30 min prior to ischemia; group 3, the same method with 3 mg.kg-1 of PGE1; group 4, 3 mg.kg-1 of PGE1, during 24 hours (12 hours prior to ischemia, and 12 hours following ischemia); group 5, 3 mg.kg-1 of PGE1, during 96 hours (12 hours prior to ischemia and 84 hours following ischemia); and group 6, sham operation. They were anesthetized with isoflurane and transient forebrain ischemia was induced by occluding bilateral common carotid arteries for 5 min. The extracranial electroencephalogram (EEG) was recorded from the electrodes placed at the vertex. During the experimental procedures, temperatures at tympanic membrane and rectum were maintained at 37.0 +/- 0.2 degrees C by means of a heating mat and control of the air temperature in all groups. After 6 days of survival, they were sacrificed, and the brain tissues were fixed for the immunohistochemical and histopathological analyses. The hippocampal CA 1 regions were stained for monoclonal anti microtubule-associated protein 2 (MAP 2), and hematoxylin and eosin. In the 4th group, EEG recovery was recognized earlier than the other groups. Immunoreactivities for MAP 2 and the number of surviving pyramidal cells after ischemia in the CA 1 regions were also well maintained. These results suggest the PGE1, has protective effects against degradation of cytoskeletal proteins and delayed neuronal death in the gerbil, and it might be due to direct protective action of cell membrane in addition to its microcirculatory improvement.

Penetration of cefpodoxime into uterine and vaginal secretions from postpartum women after a single oral dose of cefpodoxime proxetil

We evaluated the usefulness of cefpodoxime proxetil (CPDX-PR) in the treatment of puerperal infection and obtained the following results. (i) The susceptibilities of 124 clinical isolates from 85 uterine lochia samples were determined. The MIC at which the growth of Streptococcus agalactiae, Escherichia coli, and Bacteroides fragilis isolates was inhibited by 90% (MIC90) was 0.39 micrograms/ml or less. The MIC90 for Staphylococcus aureus was 3.13 micrograms/ml. (ii) Seven puerperal women received 200 mg of CPDX-PR orally. The CPDX concentration in the lochias in the uterine cavity was not statistically different from that in the vagina, suggesting that the vaginal samples, which can be obtained more safely and aseptically, can be substituted for the uterine samples. The CPDX concentration in cubital venous blood reached a peak of 1.61 micrograms/ml at 3 hours after CPDX-PR administration. The CPDX concentration in the lochias gradually increased and reached a peak of 1.20 micrograms/ml in the uterine cavity and 1.27 micrograms/ml in the vagina at 5 h after drug administration and gradually declined thereafter. These results suggest that CPDX-PR, with its good transfer to the lochia and its potent antimicrobial activity, is a promising drug for the prophylactic and therapeutic treatment of puerperal infections caused by susceptible organisms.

A study of the luteolytic mechanism of the antiprogesterone RU486 during the late-luteal phase in pseudopregnant rats

The purpose of this study was to examine the possible mechanism through which RU486 induces luteolysis during the late-luteal phase in pseudopregnant (PSP) rats. PSP rats received a subcutaneous injection of RU486 in sesame oil (5 mg/kg body weight) or sesame oil alone once a day between day 9 and day 11 of pseudopregnancy. Serial blood samples were collected on days 5, 9, 10, 11 and 12 and assayed for progesterone content. To examine the possible action of RU486 through a uterine and/or a pituitary (prolactin-dependent) mechanism, PSP rats and chronic hysterectomized PSP rats which had been hysterectomized before PSP induction received a subcutaneous injection of RU486 in sesame oil (5 mg/kg body weight), sesame oil alone, prolactin in 50% polyvinylpyrrolidone (15 IU/day), or RU486 and prolactin once a day between day 9 and day 11 of pseudopregnancy. Serial blood samples were collected on days 5, 9, 10 and 11 and assayed for progesterone content. Blood samples were also collected at 0400 h on day 12 and used for prolactin and progesterone determinations. To examine the direct effect of RU486 on corpus luteum and/or pituitary, hysterectomized rats underwent hypophysectomy and pituitary autotransplantation on dioestrus 1 and received a subcutaneous injection of RU486 in sesame oil or sesame oil alone for 3 days between day 21 and day 23 after surgery. Serial blood samples were collected on days 10, 21, 22, 23 and 24 and assayed for progesterone and prolactin contents. In ordinary PSP rats, serum progesterone levels were significantly (P < 0.01) lower in the RU486-treated group than in the control group (9 +/- 1 vs 53 +/- 7 ng/ml; mean +/- S.E.M.) on day 11. Serum prolactin levels at 0400 h on day 12 of pseudopregnancy were significantly (P < 0.05) lower in the RU486-treated group than in the control group (16 +/- 4 vs 154 +/- 44 ng/ml; mean +/- S.E.M.). The concomitant prolactin treatment reversed the luteolytic effects of RU486 on day 11 of pseudopregnancy. In hysterectomized PSP rats, RU486 also suppressed serum prolactin levels, and the concomitant prolactin treatment again reversed the luteolytic effects of RU486. In hysterectomized rats which were hypophysectomized and pituitary autotransplanted, RU486 treatment did not induce any significant changes in serum progesterone and prolactin levels. These results indicated that RU486 induced luteolysis during the late-luteal phase in PSP rats by suppressing prolactin secretion via a hypothalamic mechanism.

[Involvement of stimulatory effect of prostaglandin F2 alpha on superoxide radical production by macrophages in corpus luteum regression]

The effect of prostaglandin F2 alpha (PGF2 alpha) on superoxide radical production by macrophages was studied in pseudopregnant rats. Peritoneal macrophages prepared on day 7 or 13 of pseudopregnancy (psp) were incubated with various doses of PGF2 alpha for 90 min, and the production of superoxide radical was measured by the cytochrome C reduction method. PGF2 alpha significantly stimulated superoxide radical production by macrophages on day 13 of psp, but not on day 7 of psp. The pretreatment of macrophages with an inhibitor of protein kinase C (H7), Ca2+ channel blocker (Verapamil), Ca2+ chelators (EGTA, BAPTA), and an inhibitor of GTP-binding protein (pertussis toxin) prevented the stimulatory effects of PGF2 alpha on superoxide radical production. In conclusion, PGF2 alpha stimulated superoxide radical production by macrophages through the intracellular signal transduction pathway including activation of protein kinase C through the GTP-binding protein and Ca2+ influx, which would play important roles in the luteolytic process in psp rats.

Changes in activity of superoxide dismutase in the human endometrium throughout the menstrual cycle and in early pregnancy

To investigate the possible role of the superoxide radical and its scavenging system in the human endometrium, the immunohistochemical distribution of superoxide dismutase (SOD), activities of SOD and lipid peroxide concentrations were studied in the human endometrium throughout the menstrual cycle and in early pregnancy. The endometrial epithelium showed a positive immunostaining for Cu, Zn-SOD and Mn-SOD throughout the entire menstrual cycle and in early pregnancy. In the stroma, weak immunostaining for Cu,Zn-SOD and moderate immunostaining for Mn-SOD were observed in the predecidual cells in the late secretory phase. Decidual cells in early pregnancy showed strong immunostaining for Cu,Zn-SOD and Mn-SOD. Total SOD activity in the endometrium increased from early proliferative phase to mid-late proliferative phase and further increased in the mid-secretory phase, and decreased in the late secretory phase. The total SOD activity in the endometrium of of early pregnancy was the same level as that in the mid-secretory phase. Cu,Zn-SOD and Mn-SOD activities changed in a similar manner to total SOD activity throughout the menstrual cycle and in early pregnancy. Lipid peroxide concentration in the endometrium increased from early proliferative phase to mid-late proliferative phase and further increased in the late secretory phase. However, lipid peroxide concentration in the endometrium of early pregnancy was the same as that in the mid-secretory phase. These results suggested that the superoxide radical and its scavenging system may play an important role in the regulation of human endometrial function.

Changes in interleukin-1 production of peritoneal macrophages during estrous cycle in golden hamsters

The present study demonstrated the change in interleukin-1 (IL-1) production of peritoneal macrophages during the estrous cycle in golden hamsters and discussed its possible roles in ovarian function. Macrophages were collected from the peritoneal cavity at 0900 h on various days of the estrous cycle and incubated for 6 h in the presence of ovine pituitary LH (500 ng/ml). The IL-1 concentration in the media was measured by bioassay with the A375S2 human melanoma cell line. The number of macrophages significantly (P < 0.01) increased on estrus and proestrus compared with diestrus 1 or diestrus 2. LH-induced production of IL-1 was also greater (P < 0.01) on proestrus (292 +/- 36 pg/10(6) cells/ ml) and estrus (222 +/- 30 pg/10(6) cells/ml) than on diestrus 1 (34 +/- 15 pg/10(6) cells/ml) or diestrus 2 (117 +/- 16 pg/10(6) cells/ml). To clarify the factor inducing the changes in peritoneal macrophages, hamsters were ovariectomized on diestrus 1, and 3 weeks later the animals were treated with s.c. injections of progesterone (200 micrograms/day), testosterone (100 micrograms/day), estradiol (10 micrograms/day) or sesame oil for three days. The hamsters were killed 24 h after the last injection, and the number and IL-1 producing capacity of macrophages were determined. The number of macrophages and their response to LH to produce IL-1 were increased significantly (P < 0.01) by estradiol treatment but not by progesterone or testosterone treatment. It was concluded that the peritoneal macrophages became more sensitive to LH to produce IL-1 on proestrus and estrus in cyclic hamsters, and that these changes in macrophages, probably induced by estradiol, would play important roles in ovarian function.

Progesterone inhibits superoxide radical production by mononuclear phagocytes in pseudopregnant rats

This study investigated the changes in superoxide radical production by mononuclear phagocytes in the corpus luteum (CL) during pseudopregnancy in rats. Activity of superoxide radical production was determined by the conversion of nitro blue tetrazolium (NBT) to blue formazan deposit. Rats received 10 mg NBT via the abdominal aorta on day 3, 7, or 13 of pseudopregnancy and were autopsied 1 min later to prepare the histological sections. The cells with blue formazan deposits (NBT-positive cells) in the CL were scarce on days 3 and 7 of pseudopregnancy and significantly increased on day 13 of pseudo-pregnancy. On the other hand, simultaneous administration of 100 micrograms phorbol 12-myristate 13-acetate, which activates mononuclear phagocytes to produce superoxide radical, significantly increased the numbers of NBT-positive cells in the CL on day 7 of pseudopregnancy, but not in the CL on day 3 or 13 of pseudopregnancy. To study the possibility that superoxide radical production by mononuclear phagocytes is inhibited by progesterone on day 7 of pseudopregnancy, peritoneal mononuclear phagocytes prepared on day 7 or 13 of pseudopregnancy were preincubated with 10, 50, or 100 ng/ml progesterone for 6 h and then stimulated with phorbol 12-myristate 13-acetate. Superoxide radical production was measured by the cytochrome c reduction method. One hundred nanograms per ml progesterone significantly inhibited superoxide radical production by mononuclear phagocytes, and this inhibitory effect of progesterone was significantly blocked by the simultaneous addition of RU486 (10(-7) M). These results suggested that progesterone inhibited superoxide radical production by the mononuclear phagocytes in the CL during midpseudopregnancy in rats.

[Effect of ulinastatin on delayed neuronal death in the gerbil hippocampus]

The effect of ulinastatin on delayed neuronal death was studied in the gerbil. The animals were divided into 2 groups according to the temperatures of the temporalis muscle, tympanic membrane, and the rectum. One group consisted of 36 animals in whom the temperature was maintained at 36.5 degrees C and the another was at 38 degrees C. They were anesthetized with isoflurane and injected intravenously with 5 ml.kg-1 of normal saline solution, 100 mg.kg-1 of alpha-tocopherol, 250,000 units.kg-1 of ulinastatin, or 500,000 units.kg-1 of ulinastatin, respectively. Transient ischemia was then induced by occluding bilateral common carotid arteries for 5 min. Six days later, they were sacrificed, and the brain tissues were fixed and stained for histopathological analysis of hippocampal CA1 regions. alpha-Tocopherol and ulinastatin prevented delayed neuronal death in the 36.5 degrees C group, but did not in the 38 degrees C group. alpha-tocopherol is recognized as an intrinsic radical scavenger, and known to prevent delayed neuronal death. Compared with 100 mg.kg-1 of alpha-tocopherol, 500,000 units.kg-1 of ulinastatin had the same protective effect on delayed neuronal death at 36.5 degrees C. We concluded that administration of ulinastatin prevented delayed neuronal death at 36.5 degrees C.

Changes in lipid peroxide and antioxidant enzyme activities in corpora lutea during pseudopregnancy in rats

This study investigated the involvement of lipid peroxidation and antioxidant enzymes in the regulation of luteal function in pseudopregnant rats. The activities of superoxide dismutase (SOD), a specific scavenger of superoxide radicals, and glutathione peroxidase, a scavenger of hydrogen peroxide, and lipid peroxide concentrations were measured in the corpus luteum on days 1, 3, 5, 7, 9, 11 and 13 of pseudopregnancy. The activity of SOD in the corpus luteum gradually increased until day 9 of pseudopregnancy and decreased thereafter, in a similar manner to serum progesterone concentration. Glutathione peroxidase activity significantly increased from day 1 to day 3 and remained high until day 11 of pseudopregnancy. The concentrations of lipid peroxides in the corpus luteum increased from day 3 to day 13 of pseudopregnancy. The involvement of prostaglandin F2 alpha (PGF2 alpha) in the production of lipid peroxides in regression of the corpus luteum was investigated by administering PGF2 alpha (3 mg kg-1, s.c.) or saline on days 7, 9 and 12 of pseudopregnancy. Each group of rats was autopsied 2 h later, and SOD activity, glutathione peroxidase activity and the concentration of lipid peroxides in the corpus luteum were determined. PGF2 alpha significantly increased lipid peroxide concentrations in the corpus luteum on days 7, 9 and 12 of pseudopregnancy (approximately twofold increases on days 7 and 9, and a fivefold increase on day 12, compared with the control that received saline). The activity of SOD in the corpus luteum was significantly increased by PGF2 alpha on days 7 and 9, but not on day 12, of pseudopregnancy. PGF2 alpha did not cause any significant changes in glutathione peroxidase activity in the corpus luteum on days 7, 9 and 12 of pseudopregnancy. It is concluded that lipid peroxides play an important role in regulating luteal function in pseudopregnant rats.

Difference of myosin heavy chain expression between mesangial cells and vascular smooth muscles

Contraction of the pre- and postglomerular arteries play an important role in the regulation of glomerular blood flow. Mesangial cells may also be involved in the mechanism of this regulation, but it has not been clarified yet whether or not mesangial cells and vascular smooth muscles show an identical phenotype, especially in terms of their contractile proteins. In this study, in order to elucidate any difference in the cellular phenotypes between mesangial cells and renal vascular smooth muscles, we investigated the localization of myosin heavy chain isoforms using a monoclonal antibody against SM1 and SM2. Both SM1 and SM2 are specific to smooth muscles. SM1 is specifically expressed in smooth muscles from early development and SM2 appears after birth. In normal renal tissues, SM1 and SM2 were expressed only in the smooth muscle cells of the arterioles and small arteries. However, glomerular cells, including mesangial cells, were not stained with either anti-SM1 antibody or anti-SM2 antibody. Localization of SM1 and SM-2 was similar to that of alpha-smooth muscle actin (SM alpha-actin). Staining for SM-1 was not observed in the mesangial areas of renal tissues with glomerular disease. These results clearly indicate that mesangial cells have a different phenotype from that of vascular smooth muscle cells in terms of their contractile proteins.

Lipid peroxidation as an indicator of biocompatibility in haemodialysis

Peroxidation of cell membrane (phosphatidylcholine hydroperoxide, PCOOH) was quantitatively assessed using a chemiluminescence-HPLC system to clarify whether haemodialysis patients are damaged by oxidative stress. Patients were divided into two groups, one dialysed with conventional cellulose membranes, and the other with cellulose triacetate for 3 months, subsequently followed by a crossover study of each membrane for 3 more months. The mean value of PCOOH in haemodialysis patients was 508.5 +/- 208.7 pmol/ml (P < 0.01 vs normal controls), which showed a statistically insignificant tendency to increase during each haemodialysis session of 4 h. Two years after commencing haemodialysis, PCOOH was maintained within almost the same range, but significantly greater than normal. There was no significant tendency between an index of aortic sclerosis and plasma PCOOH. However, three patients using conventional cellulose membranes died of myocardial infarction. Plasma PCOOH increased after the commencement of haemodialysis. This tendency was more notable in patients using conventional cellulose membrane compared to the cellulose triacetate. Cellulose triacetate, which we thought to be more biocompatible, did not necessarily produce lipid peroxide. We conclude that it is very important to check production of oxygen radicals when developing new membranes.

Effects of restraint stress on luteal function in rats during mid-pregnancy

This study was undertaken to investigate the relationship between the inhibitory effect of restraint stress and the protective effect of the feto-placental luteotrophic factors on luteal function during mid-pregnancy in rats. The number of conceptuses was adjusted to one (1C group) or more than ten (FC group) on day 7 of pregnancy, and each rat received restraint stress from day 12 to day 17 of pregnancy. Restraint stress consisted of placing a rat individually in a small plastic holder three times a day for 1 h each time. Restraint stress significantly decreased serum progesterone concentration on day 17 of pregnancy in the 1C group, but not in the FC group. Restraint stress also decreased serum progesterone concentration on day 17 of pregnancy in the 1C group which received bilateral adrenalectomy on day 12 of pregnancy. The number of animals with fetal resorption in this group of rats (10 out of 14 animals) was significantly greater than in any other group of rats. The number of animals with fetal resorption in the adrenalectomized 1C group was significantly lower after daily injections of 4 mg progesterone from day 12 to day 17 of pregnancy. In the FC group of rats, even in adrenalectomized rats, restraint stress did not cause any changes in serum progesterone concentration or fetal loss. These data indicate that restraint stress is luteolytic and causes fetal loss during mid-pregnancy; this effect can be blocked by some factors from conceptuses, as occurred in the FC group.