Biomedical subjects

S Tagami

Publications and source records attributed to S Tagami.

At least 19 recordsLinked to original sources

PubMed2000

A novel protein, RTN-XS, interacts with both Bcl-XL and Bcl-2 on endoplasmic reticulum and reduces their anti-apoptotic activity.

Bcl-2 and Bcl-XL serve as critical inhibitors of apoptosis triggered by a broad range of stimuli, mainly acting on the mitochondria. We identified two members of the reticulon (RTN) family as Bcl-XL binding proteins, i.e., NSP-C (RTN1-C) and a new family member, RTN-XS, both of which did not belong to the Bcl-2 family and were predominantly localized on the endoplasmic reticulum (ER). RTN-XS interacted with both Bcl-XL and Bcl-2, increased the localization of Bcl-XL and Bcl-2 on the ER, and reduced the anti-apoptotic activity of Bcl-XL and Bcl-2. On the other hand, NSP-C interacted only with Bcl-XL, affected the localization of Bcl-XL, and reduced Bcl-XL activity, but had no effect on Bcl-2. These results suggest that RTN family proteins can modulate the anti-apoptotic activity of Bcl-XL and Bcl-2 by binding with them and can change their localization to the ER.

Amino Acid Sequence↗

PubMed2000

Tau protein is a potential biological marker for normal pressure hydrocephalus.

A biological marker for normal pressure hydrocephalus (NPH) is beneficial for evaluation of its severity and of indications for shunt operation. Tau protein was initially considered as a biological marker in cerebrospinal fluid (CSF) from Alzheimer's patients. Recently, it has been demonstrated that degeneration in the brain causes elevation of tau in CSF. Therefore, the tau level in CSF from NPH patients was evaluated. Tau levels in CSF from NPH patients were significantly higher than that in controls. The tau levels were correlated with the severity of dementia, urinary incontinence, and gait disturbance in NPH. These results suggest that CSF tau may be useful as a biological marker for NPH to determine the level of neuronal degeneration.

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PubMed1999

Bcl-2/E1B 19 kDa-interacting protein 3-like protein (Bnip3L) interacts with bcl-2/Bcl-xL and induces apoptosis by altering mitochondrial membrane permeability.

We have previously reported on cloning of the human gene encoding Bcl-2/adenovirus E1B 19 kDa-interacting protein 3-like protein (Bnip3L) and its growth inhibitory effect on cancer cells. Here we show that Bnip3L contains a motif similar to the BH3 domain which is conserved in Bcl-2 family proteins as well as containing a membrane-anchoring domain, and that Bnip3L interacts with Bcl-2 and Bcl-xL. Immunofluorescence microscopy revealed that Bnip3L was localized in the mitochondria, when in the presence of the membrane-anchoring domain. Transient expression of Bnip3L induced apoptosis of Rat-1 and HeLa cells and mutational analysis revealed that the BH3 domain and the membrane-anchoring domain were required for Bnip3L to induce cell death. Addition of recombinant Bnip3L to isolated mitochondria induced membrane potential loss and cytochrome c release both of which have been suggested to be prerequisite for apoptotic cell death. These results suggest that Bnip3L is one of the BH3-containing pro-apoptotic proteins and that it targets the mitochondria when inducing apoptosis.

Adenovirus E1B Proteins↗

PubMed1999

Inflammatory cell-mediated tumour progression and minisatellite mutation correlate with the decrease of antioxidative enzymes in murine fibrosarcoma cells.

We isolated six clones of weakly tumorigenic fibrosarcoma (QR) from the tumorigenic clone BMT-11 cl-9. The QR clones were unable to grow in normal C57BL/6 mice when injected s.c. (1x10(5) cells). However, they formed aggressive tumours upon co-implantation with a 'foreign body', i.e. a gelatin sponge, and the rate of tumour take ranged from 8% to 58% among QR clones. The enhanced tumorigenicity was due to host cell-mediated reaction to the gelatin sponge (inflammation). Immunoblot analysis and enzyme activity assay revealed a significant inverse correlation between the frequencies of tumour formation by QR clones and the levels of manganese superoxide dismutase (Mn-SOD, P<0.005) and glutathione peroxidase (GPchi, P<0.01) in the respective tumour clones. Electron spin resonance (ESR) revealed that superoxide-scavenging ability of cell lysates of the QR clone with high level of Mn-SOD was significantly higher than that with low level of the antioxidative enzyme in the presence of potassium cyanide, an inhibitor for copper-zinc superoxide dismutase (CuZn-SOD) (P<0.001). Minisatellite mutation (MSM) induced by the inflammatory cells in tumour cells were investigated by DNA fingerprint analysis after QR clones had been co-cultured with gelatin-sponge-reactive cells. The MSM rate was significantly higher in the subclones with low levels of Mn-SOD and GPchi (P<0.05) than in the subclones with high levels of both enzymes. The MSM of the subclones with low levels of both enzymes was inhibited in the presence of mannitol, a hydroxyl radical scavenger. The content of 8-hydroxydeoxyguanosine (8-OHdG) by which the cellular DNA damage caused by active oxygen species can be assessed was significantly low in the tumours arising from the QR clone with high levels of Mn-SOD and GPchi even if the clone had been co-implanted with gelatin sponge, compared with the arising tumour from the QR clone with low levels of those antioxidative enzymes (P<0.001). In contrast, CuZn-SOD and catalase levels in the six QR clones did not have any correlation with tumour progression parameters. These results suggest that tumour progression is accelerated by inflammation-induced active oxygen species particularly accompanied with declined levels of intracellular antioxidative enzymes in tumour cells.

Animals↗

PubMed1999

Increased glomerular cytosolic phospholipase A2 activity of OLETF rats with early diabetes.

In view of the potential role of prostaglandins (PGs) in development of glomerular hyperfiltration leading to diabetic nephropathy, we studied the temporal relationship of the activity of cytosolic phospholipase A2 (cPLA2), a rate-limiting enzyme for eicosanoid biosynthesis, with hyperfiltration and the histological changes in glomeruli using OLETF rats, a model for non-insulin-dependent diabetes mellitus (NIDDM). Diabetes mellitus and associated histopathological changes, which developed spontaneously by 30-46 weeks after birth of OLETF rats, were accompanied by approximately 65% increase in glomerular cPLA2 activity that showed significant correlations with elevated plasma glucose levels and creatinine clearance. Moreover, mesangial cells cultured for 5 days with high glucose exhibited approximately 2-fold higher cPLA2 activity than those cultured with physiologic level of glucose. These data suggest that increased glomerular cPLA2 activity leads to production of PGs, which may promote the progression of early diabetic glomerular hyperfiltration and subsequent diabetic nephropathy.

Aging↗

PubMed1999

Regulation of macrophage migration inhibitory factor (MIF) expression by glucose and insulin in adipocytes in vitro.

BACKGROUND: It has been reported that macrophage migration inhibitory factor (MIF) stimulated insulin secretion from pancreatic islet beta-cells in an autocrine manner, which suggests its pivotal role in the glucose metabolism. According to this finding, we evaluated MIF expression in cultured adipocytes and epididymal fat pads of obese and diabetic rats to investigate its role in adipose tissue. MATERIALS AND METHODS: The murine adipocyte cell line 3T3-L1 was used to examine MIF mRNA expression and production of MIF protein in response to various concentrations of glucose and insulin. Epididymal fat pads of Otsuka Long-Evans Tokushima fatty (OLETF) and Wistar fatty rats, animal models of obesity and diabetes, were subjected to Northern blot analysis to determine MIF mRNA levels. RESULTS: MIF mRNA of 3T3-L1 adipocytes was up-regulated by costimulation with glucose and insulin. Intracellular MIF content was significantly increased by stimulation, whereas its content in the culture medium was decreased. When the cells were treated with cytochalasin B, MIF secretion in the medium was increased. Pioglitazone significantly increased MIF content in the culture medium of 3T3-L1 cells. However, MIF mRNA expression of both epididymal fat pads of OLETF and Wistar fatty rats was down-regulated despite a high plasma glucose level. The plasma MIF level of Wistar fatty rats was significantly increased by treatment with pioglitazone. CONCLUSION: We show here that the intracellular glucose level is critical to determining the MIF mRNA level as well as its protein content in adipose tissue. MIF is known to play an important role in glucose metabolism as a positive regulator of insulin secretion. In this context, it is conceivable that MIF may affect the pathophysiology of obesity and diabetes.

3T3 Cells↗

PubMed1998

Tumor necrosis factor-alpha regulates the gene expression of macrophage migration inhibitory factor through tyrosine kinase-dependent pathway in 3T3-L1 adipocytes.

Macrophage migration inhibitory factor (MIF) has been rediscovered as a proinflammatory cytokine, pituitary hormone, and glucocorticoid-induced immunoregulator. We have recently identified the expression of MIF in adipocytes and found that tumor necrosis factor (TNF)-alpha stimulates its secretion from 3T3-L1 adipocytes. Since adipocytes are regarded as a potential source of various biologically active substances, we examined in more detail the effect of TNF-alpha on MIF expression in 3T3-L1 adipocytes in the present study. We found that TNF-alpha induced MIF mRNA in dose- and time-dependent manners. After stimulation with TNF-alpha, the amount of intracellular MIF protein was unchanged or slightly decreased, concomitant with increased release of this protein into the extracellular space. This observation indicates that TNF-alpha stimulates MIF secretion from the constitutively expressed intracellular pool of 3T3-L1 adipocytes and promotes de novo synthesis of MIF. From evaluation of the mechanism of MIF gene expression, we found that tyrosine kinase inhibitors, either genistein or herbimycin A, suppressed the MIF mRNA induction by TNF-alpha. The results suggest the possibility that upregulation of MIF mRNA expression by TNF-alpha is mediated by a tyrosine kinase-dependent pathway. Taken together, the present observations shed light on the role of MIF in the metabolism of obesity and diabetes.

3T3 Cells↗

PubMed1998

Circulating thrombomodulin and hematological alterations in type 2 diabetic patients with retinopathy.

To clarify the relationship between circulating thrombomodulin (TM) and endothelial cell damage in diabetes mellitus, plasma levels of TM were quantitated by an enzyme linked immunoabsorbant assay (ELISA) in 164 type 2 diabetes mellitus and 72 normal control subjects, and these levels were compared with those of von Willebrand factor antigen (vWf: Ag), thrombin antithrombin III complexes (TAT), plasmin-alpha2-plasmin inhibitor complexes (PIC), fibrinogen, D-dimer, urinary albumin excretion rate (AER), intima-media thickness (IMT) and plaque score of the common carotid artery assessed with high resolution B-mode ultrasonography. Plasma levels of TM, vWf: Ag, TAT, PIC, AER, IMT and plaque score were significantly increased in the diabetic patients compared to the normal control subjects. Plasma TM levels showed significant correlation with vWf: Ag (r=0.350, p<0.0001), TAT (r = 0.334, p < 0.0001), PIC (r = 0.450, p < 0.0001), AER (r = 0.334, p < 0.0001), IMT (r = 0.181, P<0.01), plaque score (r=0.385, p<0.0001). Among four groups of diabetic patients, divided based on their severity of diabetic retinopathy, there were no significant differences in age, sex, systolic and diastolic blood pressure levels, HbA,1c, or plasma lipid levels, although the plasma levels of TM, vWf: Ag, TAT, PIC, AER, IMT and the plaque score in the patients with proliferative retinopathy were significantly higher than those of the healthy controls and patients with simple retinopathy. Among the 43 normoalbuminuric patients without intima-media thickness or thickened plaque (AER<30 mg/g Creatinine, IMT<1.0 mm, plaque score = 0), plasma levels of TM, vWf: Ag, TAT, PIC were significantly higher in those patients with retinopathy than in those without retinopathy. Multivariate analysis showed TM, TAT and PIC levels to be independent predictors of diabetic retinopathy. In conclusion, circulating TM reflects endothelial cell damage in patients with diabetic retinopathy, and hypercoagulability might play an important role in endothelial cell damage.

Aged↗

PubMed1997

Identification of macrophage migration inhibitory factor in adipose tissue and its induction by tumor necrosis factor-alpha.

Macrophage migration inhibitory factor (MIF) has been rediscovered as a proinflammatory cytokine, pituitary hormone, and glucocorticoid-induced immunoregulator. A survey of tissue distribution revealed that MIF expression is not limited to T lymphocytes, but exists in several other tissues; however, its presence in adipose tissue has never been investigated. In this study, we examined the expression of MIF in adipose tissue using the rat epididymal fat pad and murine 3T3-L1 adipocytes. Northern and Western blot analyses revealed the expression of MIF mRNA and MIF protein, respectively, in both the fat pad and the adipocyte cell line. In immunohistochemistry, a positive staining reaction with an anti-rat MIF antibody was detected largely in the cytosol of adipocytes of the epididymal fat pad. To examine the production and release of MIF by adipocytes, we examined its content in the culture medium of the 3T3-L1 adipocytes. The results showed that MIF content was 1.6 +/- 0.48 ng/ml (mean +/- SD) after 24 hr culture, and the content was increased up to 9.7 +/- 2.8 ng/ml by stimulation with TNF-alpha (50 nM). Since TNF-alpha produced in adipocytes is known to induce insulin resistance, the results suggest the possibility that MIF plays an important role in the mechanism of insulin resistance often observed in obesity and diabetes via regulation of TNF-alpha expression.

3T3 Cells↗

PubMed1997

Elevation of plasma lipid peroxides in non-insulin dependent diabetics with multiple lacunar infarcts.

Our purpose was to determine whether lipid peroxides are elevated in the plasma of patients with non-insulin dependent diabetes with multiple lacunar infarcts as detected by magnetic resonance imaging (MRI), and to confirm whether peroxide levels correlate with glycemic controls and blood lipid levels. The level of lipid peroxide (measured as thiobarbituric acid reactive substances (TBARS)) was measured in 23 healthy controls and 28 diabetics showing normal MRI findings and 22 diabetics with multiple lacunar infarcts. These groups were age-matched. In patients with multiple lacunar infarcts, systolic blood pressure, diastolic blood pressure and TBARS levels were significantly higher than in diabetics without such infarcts (p < 0.05). When the diabetic patients were divided into two groups according to the presence or absence of hypertriglyceridemia or hyperglycemia, in both groups plasma TBARS levels in patients with multiple lacunar infarcts were significantly higher than in patients without such infarcts. Multivariate analysis showed systolic blood pressure and plasma TBARS levels to be independent predictors of multiple lacunar infarcts. Among diabetics, total plasma TBARS levels were positively correlated with fasting blood glucose, HbA1c and triglyceride levels, but not with total cholesterol levels and age. In conclusion plasma lipid peroxides were elevated in diabetics with multiple lacunar lesions, and are related to the metabolic imbalance of plasma glucose and lipids.

Aged↗

PubMed1995

Weakened cellular scavenging activity against oxidative stress in diabetes mellitus: regulation of glutathione synthesis and efflux.

Glutathione functions to scavenge oxidants or xenobiotics by covalently binding them and transporting the resulting metabolites through an adenosine 5'-triphosphate-dependent transport system. It has been reported that the intracellular concentration of glutathione decreases in diabetes mellitus. In order to elucidate the physiological significance and the regulation of anti-oxidants in diabetic patients, changes in the activity of the glutathione-synthesizing enzyme, gamma-glutamylcysteine synthetase, and transport of thiol [S-(2,4-dinitrophenyl)glutathione] were studied in erythrocytes from patients with non-insulin-dependent diabetes and K562 cells cultured with 27 mmol/l glucose for 7 days. The activity of gamma-glutamylcysteine synthetase, the concentration of glutathione, and the thiol transport were 77%, 77% and 69%, respectively in erythrocytes from diabetic patients compared to normal control subjects. Treatment of patients with an antidiabetic agent for 6 months resulted in the restoration of gamma-glutamylcysteine synthetase activity, the concentration of glutathione, and the thiol transport. A similar impairment of glutathione metabolism was observed in K562 cells with high glucose levels. The cytotoxicity by a xenobiotic (1-chloro-2,4-dinitrobenzene) was higher in K562 cells with high glucose than in control subjects (50% of inhibitory concentration 300 +/- 24 mumol/l vs 840 +/- 29 mumol/l, p < 0.01). Expression of gamma-glutamylcysteine synthetase protein was augmented in K562 cells with high glucose, while enzymatic activity and expression of mRNA were lower than those in the control subjects. These results suggest that inactivation of glutathione synthesis and thiol transport in diabetic patients increases the sensitivity of the cells to oxidative stresses, and these changes may lead to the development of some complications in diabetes mellitus.

Aged↗

PubMed1994

Current smoking of elderly men reduces antioxidants in alveolar macrophages.

Alveolar macrophages were prepared from 15 healthy elderly male current smokers 60.9 +/- 9.9 yr of age (mean +/- SD). Alveolar macrophages from 11 elderly male nonsmokers 66.7 +/- 8.1 yr of age served as controls. Production of oxygen radical species was higher in alveolar macrophages from current smokers than in those from nonsmokers in the presence and absence of phorbol myristate acetate (29.8 +/- 15.5 versus 13.7 +/- 8.2 mumol/10(6) cells and 3.8 +/- 1.6 versus 2.2 +/- 1.2 mumol/10(6) cells, respectively, p < 0.01). Decreases in antioxidant activity were observed in cells from smokers versus those from nonsmokers for Cu, Zn-superoxide dismutase (114 +/- 41 versus 210 +/- 73 units/mg protein, respectively, p < 0.01), glutathione S-transferase (0.217 +/- 0.091 versus 0.368 +/- 0.017 units/mg protein, p < 0.01), and glutathione peroxidase (0.736 +/- 0.779 versus 1.590 +/- 0.879 units/mg protein, p < 0.05). Immunologic estimation showed a decrease in the levels of Cu, Zn-superoxide dismutase in cells from smokers (104.3 +/- 46.4 versus 184.1 +/- 64.4 ng enzyme/mg protein, respectively, p < 0.01). Northern blot analysis of Cu, Zn-superoxide dismutase mRNA showed no apparent difference between the two groups, suggesting not the inactivation of this enzyme but a reduction of the translational step or increased proteolysis. The oxidant and antioxidant imbalance observed in elderly male current smokers may be a factor in the pathogenesis of respiratory tissue injury caused by smoking.

Aged↗

PubMed1993

Endogenous heterogeneity of relaxin and sequence of the major form in pregnant sow ovaries.

Using an extraction procedure that minimized proteolysis, followed by gel filtration, cation-exchange FPLC, and reverse-phase HPLC, the present study unambiguously showed the presence of multiple isoforms of relaxin in the ovaries of pregnant sows. Four relaxin isoforms were isolated (designated as R-I1, R-I2, R-II1 and R-III1). They had a similar migration pattern on SDS/urea PAGE, and showed no significant difference in biological activity. HPLC separation of the reduced and S-pyridylethylated relaxin variants indicated that R-I1, R-I2 and R-III1 each contained multiple relaxin molecules which showed variability of the B-chain, whereas R-II1 contained mostly a single relaxin molecule with only slight B-chain variability. R-II1 was thus considered likely to be the major form of relaxin stored in the ovary. Sequence analysis revealed that R-II1 contained 22 amino-acid residues in the A-chain and 29 residues in the B-chain, with a total molecular mass of 5814.8 Da. It was thus equivalent to CM-a' relaxin designated by Sherwood and O'Byrne (1974).

Amino Acid Sequence↗

PubMed1993

[Factors for weight loss in patients with senile dementia].

The authors investigated causes for weight loss in inpatients with senile dementia, who could take diets. The 81 patients (80 +/- 8.3 years of mean age +/- S.D., 22 males and 59 females) included 48 cases of senile dementia of Alzheimer type (SDAT) and 25 cases of multi-infarct dementia (MID). Controls consisted of 77 non-demented patients (82 +/- 9.1 years, 29 males and 48 females) who were admitted because of cerebrovascular or cardiopulmonary diseases. Demented patients showed an average of -1.8 +/- 8.5% weight change per year, while that of non-demented patients was +4.4 +/- 6.3%, resulting in a significant difference between them (p < 0.0001). Between demented males and females, there was no significant difference. In male, SDAT cases showed more weight loss than MID cases (-5.0 +/- 5.1% vs +3.3 +/- 4.2%, P = 0.003), although in females there was no significant difference between SDAT and MID. Even when patients with a wandering tendency or complications were excluded, results essentially did not change. In demented patients, weight change did not correlated with age, amount of dietary intake, length of hospital stay or serum albumin level. However, it correlated with body weight (r = 0.26, P = 0.014), ADL index (GBS-A) (r = 0.22, P = 0.04), and with Mini-Mental State Examination score (r = 0.23, P = 0.048). In multiple regression analysis, the most powerful explanatory variable in demented males was the index for cerebral atrophy. These results confirmed previous studies reporting that reduced dietary intake, complications or hyperactivity do not fully explain weight loss in demented patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Expression of peptidylarginine deiminase in the uterine epithelial cells of mouse is dependent on estrogen.

The effects of the steroid hormones estrogen and progesterone on peptidylarginine deiminase protein-L-arginine iminohydrolase, EC 3.5.3.15) levels in adult ovariectomized mouse uterus were studied. The amount of the enzyme in the uterus was considerably diminished by ovariectomy. When the mice were injected with a variety of estrogenic compounds, 17 beta-estradiol-3-benzoate, which was the most potent stimulator of uterine cell proliferation among the estrogens tested, dramatically elevated the enzyme formation of the uterus in a dose- and time-dependent fashion. Results of immunohistochemistry with the antiserum against mouse peptidylarginine deiminase demonstrated that the induction of the enzyme by the estradiol exclusively occurred at the luminal and glandular epithelia, corresponding with the previous findings in the normal estrous cycle. Furthermore, administration of the estradiol significantly increased the content of mRNA coding for peptidylarginine deiminase in uterus, indicating the evidence of regulation in pretranslation. On the other hand, progesterone alone did not restore the enzyme level of the ovariectomized mouse, but moderated the action of estrogen when given in concert with estrogen. Thus, the expression of peptidylarginine deiminase in luminal and glandular epithelia of mouse uterus is controlled by the amount of the steroid hormones estrogen and progesterone.

Animals↗

PubMed1992

Effect of insulin on impaired antioxidant activities in aortic endothelial cells from diabetic rabbits.

The defense system of aortic endothelial cells against oxidative stress was studied in alloxan-induced diabetic rabbits, and the effect of insulin on the antioxidant activities was estimated. Endothelial cells were prepared from 10 diabetic rabbits, 18 diabetic rabbits treated with insulin, and 10 age-matched controls after 17 days of diabetes. These cells were used for the estimation of glutathione (GSH) levels and its related enzyme activities. The antioxidant activities in these endothelial cells from diabetic rabbits were compared with those from control subjects. The concentration of GSH decreased in diabetic rabbits (1.6 +/- 0.2 nmol/mg protein [mean +/- SD] v 3.7 +/- 0.6 nmol/mg protein). Decreases in the activities of Cu, Zn-superoxide dismutase (Cu,Zn-SOD) (62.7 +/- 11.0 U/mg protein v 172.9 +/- 20.2 U/mg protein), catalase (7.6 +/- 2.1 U/mg protein v 12.3 +/- 3.2 U/mg protein), and GSH peroxidase (134.0 +/- 27.0 mU/mg protein v 179.1 +/- 26.2 mU/mg protein) were observed. The activities of other GSH-related enzymes such as GSH S-transferase or GSH reductase did not change in endothelial cells from diabetic rabbits. Most of these antioxidant activities were prevented when diabetic rabbits were treated with insulin (1 to 2 U/kg/d). These antioxidant activities were also determined in the diabetic liver and kidney. Similar decreases in the cellular defense activities and prevention of the decrease in activities by insulin were observed in the diabetic liver, while these antioxidant enzyme activities in the kidney were resistant to diabetic conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

A new technique for the precise location of lactate and malate dehydrogenases in goat, boar and water buffalo spermatozoa using gel incubation film.

Gel incubation film, which contained gelatin to prevent the diffusion of enzyme during chemical reaction and phenazine methosulfate to operate as a hydrogen acceptor between NADH and tetrazolium, was used and light microscopy revealed that lactate dehydrogenase was located in the head and tail of the spermatozoa as well as in the midpiece, whereas malate dehydrogenase was confined to the midpiece in spermatozoa of the animals examined. In goat spermatozoa, lactate dehydrogenase was associated mainly with the inner acrosomal membrane in the head, the mitochondrial matrix in the midpiece and with flagellar fibrils in the tail, whereas malate dehydrogenase was present only in the mitochondrial matrix.

Animals↗

PubMed1992

Evidence for immunoreactive relaxin in boar seminal vesicles using combined light and electron microscope immunocytochemistry.

Light-microscope immunocytochemistry using the peroxidase-antiperoxidase technique and a polyclonal rabbit antiserum raised against purified porcine relaxin showed that cytoplasmic immunostaining for relaxin could be visualized in the epithelial cells of the seminal vesicle. No relaxin immunoreactivity was seen in the testis, epididymis, ductus deferens, prostate or bulbo-urethral gland. A ten times higher concentration of porcine relaxin antiserum was necessary to achieve immunostaining in the seminal vesicle comparable to that in the corpora lutea of pregnant sows. Ultrastructural examination showed that the epithelial cells of the boar seminal vesicle resembled typical protein-secreting cells with prominent rough endoplasmic reticulum and well-developed Golgi apparatus. The most striking feature of these cells was the accumulation of granules with a limiting membrane, which ranged from 200 to 600 nm in diameter and contained flocculent material of moderate electron density. Electron-microscope immunocytochemistry using the protein A-gold technique and relaxin antiserum demonstrated that the granules were the only intracellular organelles that showed immunoreactivity for relaxin. These results indicate that a relaxin-like substance is present in boar seminal vesicles and that the subcellular site of its localization is the granules, suggesting that the seminal vesicle produces and stores a relaxin-like substance, but that it is present at much lower concentrations than in the corpora lutea of pregnant sows.

Animals↗