Biomedical subjects

N Sugino

Publications and source records attributed to N Sugino.

At least 37 records · Page 2Linked to original sources

PubMed1999

Suppression of intracellular superoxide dismutase activity by antisense oligonucleotides causes inhibition of progesterone production by rat luteal cells.

Superoxide radicals are known to inhibit progesterone production by luteal cells and have also been reported to cause apoptosis in various cells. The corpus luteum has an antioxidant enzyme to scavenge superoxide radicals: copper-zinc superoxide dismutase (Cu, Zn-SOD). However, it remains unknown how the decrease in intracellular Cu,Zn-SOD activity influences luteal function. This study was therefore undertaken to investigate whether suppression of intracellular Cu,Zn-SOD activity inhibits progesterone production by rat luteal cells and causes apoptosis. To suppress intracellular Cu, Zn-SOD activity, dispersed rat luteal cells were incubated with Cu, Zn-SOD antisense oligonucleotides. The 48-h treatment with antisense oligonucleotides (10 microM) inhibited Cu,Zn-SOD activity by 50% and Cu,Zn-SOD mRNA level by 30%, whereas sense oligonucleotides used as the control had no effect. Progesterone concentration in the medium was significantly decreased by the 48-h treatment with antisense oligonucleotides in the presence of hCG, and this inhibitory effect was completely blocked by the simultaneous addition of N-acetyl-L-cysteine, an antioxidant. Treatment with antisense oligonucleotides caused no significant change in the percentage of apoptotic cells as morphologically evaluated by the nuclear staining with Hoechst dye. In conclusion, the decrease in intracellular Cu, Zn-SOD activities inhibits progesterone production by rat luteal cells, which may be mediated by superoxide radicals, suggesting that intracellular Cu,Zn-SOD plays important roles in the regulation of luteal function.

Animals↗

PubMed1999

Changes in interleukin-1beta mRNA expression in the rat ovary during the estrous cycle in response to lipopolysaccharide.

The changes in interleukin-1 (IL-1) beta mRNA expression and the number of macrophages were studied in the ovary during the estrous cycle in rats and after intraperitoneal injection of lipopolysaccharide (LPS, 2 mg/body) 2 hours before autopsy. IL-1beta mRNA expression was very low in the ovary, and there was no statistically significant change during the estrous cycle. Hybridization signals of IL-1beta mRNA were localized intensely in the thecal layer, moderately in the corpora lutea, and slightly in granulosa cells of the ovary during the cycle. The number of macrophages seen mainly in the hilum and interstitium significantly increased on proestrus compared with other estrous days. LPS significantly increased IL-1beta mRNA expression on each day with the highest response to LPS at 1500 h on proestrus, and caused an increase in the number of macrophages in the ovary within 2 hours. These results indicate that IL-1beta mRNA expressions are low during the estrous cycle in rats, and proestrus is the day of maximal IL-1beta synthesis in response to LPS. The increase in IL-1beta synthesis caused by LPS might be due to at least the influx of macrophages into the ovary.

Animals↗

PubMed1999

Changes in nitric oxide synthase activity in the ovary of gonadotropin treated rats: the role of nitric oxide during ovulation.

Immature rats receiving equine chorionic gonadotropin (eCG) and human CG (hCG) were used to study the time course changes in nitric oxide synthase (NOS) activity in the ovary during ovulation. To study the role of NO in ovulation, the effects of intrabursal injection of L-N(G)-monomethylarginine (L-NMMA, 125 microg/20 microl/bursa), a NOS inhibitor, on the number of ova shed were also examined. Rats were sacrificed at -48, 0, 3, 6, 9, 12, and 24 h after hCG injection, and the ovaries were collected for the NOS activity assay, Western blotting, NADPH-diaphorase histochemistry and immunohistochemistry. Total NOS and constitutive NOS activities in the ovary increased significantly at 9 h after hCG injection and the values remained high thereafter. Inducible NOS (iNOS) activity was detectable as a small peak at 3 and 6 h after hCG injection. Endothelial NOS (eNOS) protein production increased after hCG injection with a peak at 12 h, whereas iNOS protein production decreased at 12 and 24 h after hCG injection. NADPH-diaphorase positive cells increased at the thecae of growing follicles after hCG injection, appeared at mural granulosa cells before ovulation, and were detected in newly formed corpora lutea, which coincided with the results in eNOS positive cells by immunohistochemistry. L-NMMA given to rats at 5 or 7 h after hCG was most effective in reducing the number of ova shed. These results indicate that the NOS activity and NOS positive cells increased after hCG injection, and that eNOS was likely the main NOS increasing in the ovary during ovulation. It is concluded that NO produced between 5 and 9 h after hCG might play a supportive role in ovulation.

Animals↗

PubMed1999

Regulation and role of the insulin-like growth factor I system in rat luteal cells.

The relationship between insulin-like growth factor I (IGF-I), a hormone which has potent metabolic effects and stimulates protein synthesis, and prolactin and oestradiol was examined to investigate a possible mechanism for the luteal cell hypertrophy that is responsible for the increase in size of the corpus luteum. A luteal cell line (GG-CL) derived from large luteal cells of the pregnant rat corpus luteum was used. IGF-I, IGF-I receptor and oestrogen receptor beta mRNA contents were determined by semiquantitative RT-PCR. The results revealed that prolactin upregulates the expression of IGF-I mRNA in luteal cells, but not that of its receptor. IGF-I had no effect on the expression of its receptor but caused a dose-related increase in the expression of oestrogen receptor beta. Furthermore, whereas IGF-I upregulated oestrogen receptor beta expression, oestradiol downregulated expression of mRNA for both IGF-I and its receptor. This effect of oestradiol is not mediated through progesterone which is stimulated by oestradiol in the corpus luteum. The developmental studies indicate that mRNA for IGF-I and its receptor are not expressed in tandem throughout pregnancy. Whereas the receptor mRNA is expressed at higher concentrations in early pregnancy, that of its ligand is highly expressed close to parturition. Collectively, the results indicate that prolactin stimulates luteal IGF-I production, which in turn acts on the luteal cell to stimulate expression of oestrogen receptor beta. Luteal cells with increased oestrogen receptor beta can respond fully to oestradiol, leading to cell hypertrophy.

Analysis of Variance↗

PubMed1998

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.

Albumins↗

PubMed1998

A newly developed on-line monitoring system for the determination of serum electrolytes and urea during hemodialysis.

Continuous monitoring of serum solute concentrations throughout a dialysis session could be beneficial for the prevention of intradialytic morbidity such as hypotension and for the confirmation of dialysis adequacy. In this paper, we introduce a new on-line monitoring system for use during hemodialysis sessions, a system developed for the continuous observation of serum biochemical data. Using this system, we also show the possibility of clinical applications. Intradialytic hypotension could be prevented by the observation of filtrate sodium concentration and the control of dialysate sodium concentration. The termination of a dialysis session could be decided by the observation of the filtrate urea nitrogen, on the basis of the Kt/V urea ratio. Because monitoring for other solutes such as calcium and creatinine is theoretically available, clinical applications will continue to increase in the future.

Adult↗

PubMed1998

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.

Animals↗

PubMed1998

Hormonal regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase messenger ribonucleic acid in the rat corpus luteum: induction by prolactin and placental lactogens.

The corpus luteum expresses two enzymes that scavenge superoxide radicals and protect the cells from their toxic activities: cytosolic copper, zinc-superoxide dismutase (Cu,Zn-SOD) and mitochondrial manganese-SOD (Mn-SOD). The present study was undertaken to investigate whether the mRNA expression of each of these enzymes is regulated by luteotropic hormones. Cu,Zn-SOD and Mn-SOD mRNA levels were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). We first examined the effects of prolactin (PRL) on Cu,Zn-SOD and Mn-SOD mRNA expression in the corpus luteum. Hypophysectomy of Day 3 pregnant rats caused a sharp decline in both Cu,Zn-SOD and Mn-SOD mRNA levels, which was completely reversed by PRL administration. To further examine the effects of PRL and rat placental lactogen (rPL) on the expression of these enzymes, either primary luteinized granulosa cells or temperature-sensitive simian virus-40 transformed luteal cells (GG-CL) were cultured with different doses of PRL or rPL. These hormones induced a remarkable increase in Cu,Zn-SOD and Mn-SOD mRNA levels in both primary luteinized granulosa cells and GG-CL cells. Interestingly, whereas PRL up-regulated the expression of the SOD in luteal cells, other luteotropic hormones such as estradiol and dexamethasone inhibited both SOD mRNA expression while progesterone had no effect. In conclusion, PRL and PRL-like hormones induce a protective ability against toxic oxygen radicals by stimulating the expression of SODs, a phenomenon that may play an important role in maintaining luteal cell integrity and steroidogenic capacity.

Animals↗

PubMed1998

Melatonin directly suppresses steroid production by preovulatory follicles in the cyclic hamster.

The purpose of these studies was to investigate the effects of melatonin on the production of steroids (progesterone, testosterone, and estradiol) and cAMP by preovulatory follicles and to examine changes in melatonin concentrations in the ovary during the estrous cycle. Adult cyclic hamsters were used in this study. Melatonin concentrations in the ovary, pineal gland, and serum were measured at mid-light and mid-dark during the estrous cycle. Effects of melatonin on steroidogenesis by preovulatory follicles, thecae, and granulosa cells were examined, and its effect on cAMP production by preovulatory follicles was also investigated. Melatonin (0.1-10 ng/ml) had no effect on steroid production in the absence of hCG, but melatonin decreased progesterone and estradiol production by preovulatory follicles in a dose-dependent and time-dependent manner in the presence of hCG (100 mIU/ml). The target of melatonin was thecae but not granulosa cells, and melatonin significantly reduced cAMP production by preovulatory follicles. Melatonin concentrations in the ovary showed a similar phasic variation with high levels during mid-dark and low during mid-light, as in the pineal gland and serum. These results show that the ovarian melatonin levels also exhibit a circadian rhythm and suggest that the high melatonin milieu in the ovary may induce gonadal regression in the cyclic hamster.

Animals↗

PubMed1998

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.

Animals↗

PubMed1998

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.

Animals↗

PubMed1998

The expression of interleukin-6 in the pregnant rat corpus luteum and its regulation by progesterone and glucocorticoid.

Interleukin (IL)-6, a multifunctional cytokine originally described as a T cell-derived factor, is also produced by different cell types, and it influences a wide variety of physiological and pathophysiological processes. Recent studies further suggest that IL-6 has a role in down-regulating hormone production by endocrine organs and can negatively affect the steroidogenic capacity of both ovaries and testes. Thus, the aims of this investigation were to examine whether IL-6 plays a role in luteolysis and, more specifically, to determine whether luteal cells express the IL-6 gene, whether this expression is developmentally and hormonally regulated in pregnancy, and whether the corpus luteum could be a target for IL-6 action. Using semiquantitative RT-PCR, messenger RNA (mRNA) encoding both components of the IL-6 receptor [the ligand-binding subunit (IL-6 R) and the IL-6 R-associated signal transducer (gp130)] were found to be highly expressed in corpora lutea throughout pregnancy. In contrast, IL-6 mRNA expression was barely detectable from day 4 through the end of pregnancy, whereas a sharp and abrupt expression of IL-6 mRNA occurred immediately after parturition. Although the corpus luteum does not express IL-6 mRNA during most of pregnancy, it could be induced to express this gene with an in vivo injection of the bacterial endotoxin, lipopolysaccharide. In addition, when corpora lutea from day-15 pregnant rats were isolated and maintained in culture, IL-6 mRNA that was undetectable at 0 h increased in a time-related manner and reached significant levels after 4 h of incubation, followed by a similar increase in IL-6 protein secreted in the culture media. Isolation of the small and large luteal cells by elutriation indicated that both cell populations can secrete IL-6 in culture. The apparent ability of luteal cells to spontaneously express IL-6 in vitro, together with the lack of IL-6 expression during most of pregnancy, led us to examine whether the IL-6 gene is silenced throughout pregnancy by luteotropic hormones. Corpora lutea from day-15 pregnant rats were cultured in the presence of different doses of progesterone; the synthetic glucocorticoid, dexamethasone; 17beta-estradiol; and PRL. Progesterone and dexamethasone markedly inhibited IL-6 mRNA expression, whereas 17beta-estradiol had a minimal inhibitory effect, and PRL did not affect IL-6 mRNA expression. In summary, results of this investigation have revealed that the rat corpus luteum expresses the IL-6 receptor system and that luteal cells are able to secrete IL-6. However, IL-6 gene expression is silenced during most of pregnancy, probably by the high levels of progesterone locally produced in the corpus luteum. The salient finding that progesterone and glucocorticoid strongly inhibit the expression of IL-6 in the corpus luteum suggests that one important luteotropic role of progesterone and glucocorticoids could be to prevent the expression of IL-6, which might have a deleterious effect on luteal function.

Animals↗

PubMed1998

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.

Animals↗

PubMed1997

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.

Adult↗

PubMed1997

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.

Animals↗

PubMed1997

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.

Amino Acids↗

PubMed1997

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.

20-Hydroxysteroid Dehydrogenases↗

PubMed1997

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.

Animals↗