The senescence marker protein (SMP-2) of the rat liver: purification, immunochemical characterization and age-dependent regulation

In vitro translation of total rat hepatic mRNAs has identified a 31 kilodalton senescence marker protein (SMP-2) which is present in higher amounts in prepubertal and senescent males than in the post-pubertal adult male (more than 10-fold). SMP-2 is an androgen-repressible protein. The negative regulation of the SMP-2 gene activity by androgen accounts for its increased expression during the androgen insensitive states of the prepubertal and senescent livers, and its constitutive expression in the female liver. A combination of separation procedures including salt fractionation, chromatofocusing, ion-exchange chromatography and preparative gel electrophoresis have led to the purification of SMP-2 to apparent homogeneity. The purified protein showed the same electrophoretic mobility as the sex- and age-specific in vitro translation product of hepatic mRNAs. The polyclonal antibody to SMP-2 was produced in the rabbit. The antibody selectively reacted with the 31 kDa sex- and age-specific translation product of hepatic mRNAs. Western blot analysis of the liver cytosol confirms monospecificity of the antiserum, as well as age- and sex-dependent changes in the tissue level of SMP-2. Histochemical staining of liver sections with the antiserum reveals a preferential periportal localization of SMP-2 in the hepatocytes. This finding is in marked contrast to the androgen-inducible alpha 2u globulin which is preferentially synthesized and localized in the pericentral hepatocytes. Thus, the zonal distribution of SMP-2 correlates with polarized androgen sensitivity of the hepatocytes within the liver lobule.

A study of the impact of health education inparted to school children on their knowledge, attitude and practice in regard to personal hygiene

Education concerning prevailing health problems and the method of preventing and controlling them was considered to be one of the first eight essential activities in primary health care. Hence this study was attempted to assess the impact of health education on the knowledge, attitude and practices of school children aged 10-14 years in two secondary schools situated in Burdwan District of West Bengal. For this purpose health education was imparted by a team consisting of Medical Officer and Paramedical staff. Education was given on personnel hygiene. The entire education programme was arranged in such a way that the course could be completed in six months time. The knowledge, attitude and practice status of the students was assessed before imparting training, twice during the training period at an interval of three months and finally after 9 months from the start of training. The evaluation was done with the help of scoring. The results indicated that the health knowledge of the student significantly improved after education. Attitude of the students towards personal hygiene also improved significantly after education. The practice of personal hygiene improved significantly as well. The present study also revealed that the improvement in health practice was not commensurating with the improvement of knowledge and attitude after education.

Androgen regulated expression of the alpha 2u-globulin gene in pancreatic hepatocytes of rat

Under a copper-deficient regimen, pancreatic cells in the adult rat can be found to undergo differentiation into hepatocytes. Pancreatic hepatocytes induced in male and female rats were examined for the expression of the androgen-inducible hepatic protein, alpha 2u-globulin. Alpha 2u-Globulin protein was demonstrable by immunoperoxidase method in all the pancreatic hepatocytes of male rats. Northern blot analysis confirmed the presence of 1.3 kb alpha 2u-globulin mRNA transcript in the pancreas of male rats with hepatocytes. Orchiectomy resulted in marked decrease of alpha 2u-globulin protein and its mRNA. Administration of dihydrotestosterone to castrated rats resulted in increased levels of alpha 2u-globulin mRNA and the amount of alpha 2u-globulin protein in the pancreatic hepatocytes. Unlike normal males, in intact and ovariectomized females alpha 2u-globulin was not detectable in pancreatic hepatocytes. These results indicate that similar to hepatic parenchymal cells pancreatic hepatocytes synthesize alpha 2u-globulin under androgenic regulation. Furthermore, unlike in liver where it is expressed predominantly in perivenular and midlobular hepatocytes, there is no localized difference in the expression of this gene in the transdifferentiated pancreatic hepatocytes.

Structure and regulation of the senescence marker protein 2 gene promoter

The liver-specific expression of the senescence marker protein 2 (SMP-2) in the male rat is markedly reduced during the androgen-sensitive state of young adulthood, whereas it is up-regulated during the androgen-insensitive phases of prepuberty and senescence. Nuclear runoff studies show that the age-dependent changes in SMP-2 expression are due to transcriptional regulation of the gene. In order to explore the mechanism of the regulatory process, we have cloned the upstream flanking regions of two distinct SMP-2 genes (SMP-2A and SMP-2B) and established their nucleotide sequence. These clones contain approximately 2.2 kb of the 5'-flanking sequence, exons 1 and 2, the first intron, and a portion of the second intron. The SMP-2 genes, as well as the upstream sequences, contain the sequence motifs for a number of cis-acting regulatory elements, such as the hepatocyte-specific element (HP1) and the androgen response element (ARE). S1 nuclease and primer extension analyses have established the transcription initiation sites for these genes. For functional analysis of the upstream sequences, we have constructed a hybrid plasmid containing the SMP-2A gene sequence (-1970 to +38 bases) fused to the structural gene for chloramphenicol acetyl-transferase (CAT). Upon transfection into rat hepatoma cells (FT02B), this construct was able to drive expression of the CAT gene. The same construct, however, failed to function in fibroblast-derived L cells, indicating tissue-specific regulation of the construct promoter.

Expression of the human inhibin alpha-subunit gene in preovulatory granulosa-theca cells

Inhibin, a gonadal peptide that suppresses pituitary follicle-stimulating hormone, with lesser or no effect on luteinizing hormone, has recently been purified and the complementary deoxyribonucleic acid sequences cloned. Inhibin contains two subunits, labeled alpha-subunit and beta-subunit. Here we report for the first time the detection of human inhibin alpha-subunit gene expression in preovulatory granulosa-theca cells by Northern analysis. The transcript is the same size as previously reported for human placenta and corpus luteum, suggesting that the same gene is being expressed in all three tissues. These findings are consistent with previously reported Southern analysis of deoxyribonucleic acid, which showed only one copy of the alpha-inhibin gene in the human genome. Thus current data strongly suggest that there is only one copy of the inhibin alpha-subunit gene in the human genome, and this same gene is expressed in granulosa-theca cells, corpus luteum, and placenta.

A time-course study on effects of aluminium on mitotic cell division in Allium sativum

Cytotoxic effects of aluminium sulphate on root-tip cells of Allium sativum during a time-course study and during recovery were observed. The endpoints considered were mitotic index and frequencies of aberrant cells and micronuclei induced. Chronic exposure induced mitotic depression and abnormal cells to a degree directly proportional to the concentration used and the period of treatment up to 24 h. A reduction of the early higher level of toxicity was noticed following 48 h of treatment and subsequent recovery in aluminium-free nutrient media in experiments carried out with lower concentrations.

Loss of androgenic induction of alpha 2u-globulin gene family in the liver of NIH black rats

Unlike all known strains of rat, the androgen-inducible alpha 2u-globulin gene family is totally silent in the liver of NIH black (NB) rats. No endocrinological or reproductive abnormalities are apparent, and the mRNA for the androgen-repressible hepatic protein SMP-2 is normally regulated in these animals. Furthermore, immunoblot analysis shows a normal level of the male-specific cytoplasmic androgen-binding protein. Cross-breeding of the NB male and Sprague-Dawley female shows that the hybrid male in the F-1 generation regains the androgen-dependent expression of alpha 2u-globulin in the liver. These results along with the observation of high constitutive level of alpha 2u-globulin mRNA in the preputial gland of NB rats indicate a tissue- and gene-specific regulatory defect which prevents androgenic induction of alpha 2u-globulin in the liver.

Morphometric analysis of thyroid gland in adult north Indian population by nuclear imaging

A detailed retrospective morphometric analysis of thyroid gland in adult north Indian subjects using scintillation imaging has been done. Many parameters were found to be significantly different as compared to non-Indian population. Utility of this analysis has been discussed.

Purification and immunochemical characterization of the cytoplasmic androgen-binding protein of rat liver

The cytoplasmic androgen-binding (CAB) protein of the male rat liver has been implicated to play a role in the androgen-dependent regulation of alpha 2u-globulin synthesis. The liver of the adult male rat contains about 50 fmol of specific high-affinity androgen-binding activity per milligram of total cytosolic protein. Photoaffinity labeling with [3H]R-1881 followed by SDS-polyacrylamide gel electrophoresis and autoradiography shows that the CAB is a 31-kilodalton protein. By means of DEAE-cellulose chromatography and preparative SDS-polyacrylamide gel electrophoresis, we have purified the CAB protein to electrophoretic homogeneity and have raised polyclonal rabbit antiserum that is monospecific to this protein. In the sucrose density gradient, the antiserum reacted with the androgen-binding component of the male liver cytosol prelabeled with tritiated dihydrotestosterone. Western blot analysis of the liver cytosol showed that the antiserum recognizes only the 31-kDa androgen-binding component. Such immunoblotting also showed that unlike the young adult, the androgen-insensitive states during prepuberty and senescence are associated with a marked reduction in the hepatic concentration of the immunoreactive CAB protein. No immuno-chemical cross-reactivity between CAB and another androgen-binding component of Mr 29K (which is associated with androgen insensitivity during prepuberty and senescence) was observed. The latter finding favors the possibility that 31- and 29-kDa androgen-binding components may have distinct sequence structure.

Effect of temperature on aflatoxin production in Mucuna pruriens seeds

This paper describes the effect of temperature on the level of aflatoxin production in Mucuna pruriens seeds. The highest level of aflatoxin B1 (1.75 micrograms/g) was detected in the samples incubated at 25 degrees C for three weeks. At 20, 30, and 35 degrees C, aflatoxin levels were 0.30 to 0.56, 0.37 to 1.20, and 0.26 to 0.65 micrograms/g, respectively. The lowest concentration of aflatoxin B1 (0.10 to 0.29 microgram/g) was produced at 15 degrees C.

Alpha 2u-globulin in modified sebaceous glands with pheromonal functions: localization of the protein and its mRNA in preputial, meibomian, and perianal glands

alpha 2u-Globulin, the principal urinary protein of the male rat, has extensive sequence homology with many lipid binding proteins. The highest concentration of alpha 2u-globulin is found in the preputial gland, a holocrine secretory organ with pheromonal function. Meibomian and perianal glands are two other modified sebaceous glands with holocrine secretory cycles and pleiomorphic peroxisomes capable of synthesizing pheromonal lipids. Immunocytochemical examination shows the presence of alpha 2u-globulin in the acinar cells of all three of these modified sebaceous glands. Whereas in the preputial gland all of the acinar cells exhibit immunoreactivity, in the meibomian and perianal glands only selective cells contain alpha 2u-globulin. In the case of the preputial gland, in addition to the acinar cells some stratified epithelial cells also were immunoreactive. In the perianal and meibomian glands, keratinocytes lining nearby hair shafts and select cells of accessory oil glands stained for alpha 2u-globulin. In situ hybridization with a cloned cRNA probe confirmed the immunocytochemical data. Presence of the alpha 2u-globulin mRNA in these glands was also established by Northern blot analysis. Immunoelectron microscopic examination of preputial alpha 2u-globulin showed the presence of this protein in secretory granules of various maturational stages. Immunolabeled alpha 2u was also found in attached vesicles containing protein and lipid inclusions. The lytic cells were not only loaded with alpha 2u-globulin but also contained sharp-edged, irregularly shaped electron-dense granules which stained heavily for this protein. Specific localization of alpha 2u-globulin and its mRNA in three pheromone-producing sebaceous glands and its structural homology with known lipid binding proteins indicate a pheromone carrier role of alpha 2u-globulin.

Calorie restriction delays age-dependent loss in androgen responsiveness of the rat liver

We have shown that restricted calorie intake retards age-associated loss in androgen responsiveness of the rat liver. Sustained androgen receptivity delays age-dependent decline in the synthesis of the androgen-inducible alpha 2u globulin and derepression of the androgen-repressible senescence marker protein (SMP-2). Quantitation of mRNAs for alpha 2u globulin and SMP-2 in the liver of animals of various ages maintained on either ad libitum or restricted diets revealed that, although the 27-month-old ad libitum-fed rat had only 5% as much alpha 2u mRNA as the 6-month-old rat, the mRNA level was as high as 45% in the 27-month-old food-restricted rat. Conversely, the 27-month-old food-restricted rat had a much reduced amount (45%) of SMP-2 mRNA compared to the age-matched control that was allowed unlimited access to food. Furthermore, we have correlated the effect of dietary restriction on age-dependent changes in specific gene expression with the hepatic level of the immunoreactive cytoplasmic androgen-binding (CAB) protein. We observed that senescence in the male causes a substantial decrease in the circulating level of testosterone. However, dietary restriction does not retard the rate of decline in the plasma level of the male hormone during aging. These results indicate that age-dependent changes in the expression of androgen-responsive genes (alpha 2u globulin and SMP-2) reflect changing androgen sensitivity and that food restriction may directly influence the androgen receptivity of the liver.

32P-postlabeling analysis of 1-nitropyrene-DNA adducts in female Sprague-Dawley rats

The 32P-postlabeling technique was used to qualitatively establish the pattern of DNA adduct formation in mammary tissue and liver following administration of 1-nitropyrene to female Sprague-Dawley rats. 1-Nitropyrene (100 mg/kg b.w.) was administered by gavage in trioctanoin and the rats were sacrificed 24 h later. DNA was isolated from mammary fat pads and liver, enzymatically hydrolyzed to deoxyribonucleoside-3'-monophosphates and then converted to [5'-32P]3',5'-bisphosphates. The polyethyleneimine-cellulose (PEI-cellulose) TLC 32P-fingerprints revealed the presence of multiple putative adducts in the mammary fat pads and in the livers. To investigate the role of nitroreduction in the formation of these adducts, calf thymus DNA was incubated with [3H]1-nitropyrene in vitro in the presence of xanthine oxidase. The DNA was isolated and analyzed by the 32P-postlabeling technique. A major adduct spot was detected and confirmed as N-(deoxyguanosin-8-yl)-1-aminopyrene. This adduct cochromatographed with a minor in vivo adduct of DNA obtained from mammary fat pads and livers. However, the major adducts detected in vivo did not appear to originate from simple nitroreduction of 1-nitropyrene. The results of this study suggest that other metabolic pathways, such as ring oxidation, or ring oxidation followed by nitroreduction, may be responsible for the putative 1-nitropyrene-DNA adducts observed in mammary fat pads and livers of female Sprague-Dawley rats.

Cloning, sequencing, and regulation of rat liver carnitine octanoyltransferase: transcriptional stimulation of the enzyme during peroxisome proliferation

Several complementary DNAs for the peroxisomal enzyme carnitine octanoyltransferase (COT), cloned in the expression vector lambda gt11, have been isolated. Together, these clones cover 2143 bp of the COT cDNA sequence with an open reading frame for 523 amino acids. Northern analysis showed the mRNA size for this enzyme to be 3.5 kilobases. The 523 residue long amino acid sequence amounts to a molecular mass of 60,269 daltons, indicating that the cloned cDNAs contain most or all of the coding sequence for COT (Mr approximately 62,000). Hybridization studies showed that the increased COT activity in the liver of rats, fed the potent peroxisome-proliferating drug Wy-14,643, is associated with a more than 40-fold rise in the steady-state level of the COT mRNA.

Hydrocarbon-induced hyaline droplet nephropathy in male rats during senescence

Male rats administered unleaded gasoline rapidly develop nephropathy characterized by accumulation of hyaline droplets in cells of the proximal convoluted tubules (PCT). This acute response is implicated in development of renal carcinoma in male rats exposed chronically to wholly volatilized gasoline. A major constituent of hyaline droplets is alpha 2 mu-globulin, a protein of hepatic origin for which the rate of synthesis declines during aging. Little information, however, is presently available on possible age-dependent susceptibility of male rats to hydrocarbon-induced nephropathy. In kidneys of untreated male Fischer 344 rats the number of constitutive hyaline droplets declined progressively with increasing age. Electrophoresis of renal cortical homogenates revealed a protein with Mr about 18 X 10(3), probably alpha 2 mu-globulin, in young (3.5 months old) male rats and total absence of this protein in aged (26 months old) males. RIA confirmed that constitutive levels of renal and hepatic alpha 2 mu-globulin in old rats were less than 1.5% of those in young adults. Unleaded gasoline (0.4 ml/kg/day, po, 5 days) caused accumulation of hyaline droplets in renal PCT of 3.5-month-old males accompanied by a marked increase (about twofold) in the renal content of alpha 2 mu-globulin, whereas the same treatment was without effect in 26-month-old rats. Finally, in the renal cortex of young rats the activities of the lysosomal proteases cathepsin B and D were increased following gasoline administration, presumably in response to protein accumulation. However, in 26-month-old rats cathepsin B activity was unaffected, while cathepsin D was increased by gasoline administration. Thus, we conclude that animal age is an important determinant in the development of hydrocarbon-induced nephropathy and only rats which produce large amounts of alpha 2 mu-globulin are susceptible to development of this pathology.

Induction of theophylline toxicity and inhibition of clearance rates by ranitidine

PURPOSE

Theophylline is metabolized by the hepatic microsomal oxidase system, as is ranitidine, although the latter has a much lower affinity for the system. The incidence of theophylline toxicity is rare when the two drugs are administered simultaneously. We observed the development of clinical and chemical toxicity in three elderly patients receiving oral theophylline therapy for chronic obstructive pulmonary disease after the administration of ranitidine therapy for peptic ulcer disease.

PATIENTS AND METHODS

Three patients with chronic obstructive pulmonary disease who had been receiving theophylline for prolonged periods of time were studied. Two patients presented with complaints of epigastric pain, which was attributed to acid-peptic disease; the other patient presented with hematemesis, which was shown to be due to gastric and duodenal ulcers. Ranitidine was administered for treatment of acid-peptic disease. Theophylline clearance rates were determined before, during, and after ranitidine treatment. When symptoms of theophylline toxicity developed, the dose of theophylline was either stopped or reduced. Subsequently, patients were readministered their usual dose of theophylline.

RESULTS

The effect of simultaneous administration of both drugs resulted in similar reductions in theophylline clearance rates. Serum theophylline levels returned to pretreatment values after cessation of ranitidine treatment. In one patient, rechallenge with ranitidine during steady-state theophylline treatment resulted in recurrence of clinical and chemical theophylline toxicity.

CONCLUSION

These observations suggest that treatment with ranitidine may cause clinically apparent interactions with theophylline since both drugs are metabolized by the same cytochrome P-450 isozymes.

Leupeptin-mediated alteration of renal phagolysosomes: similarity to hyaline droplet nephropathy of male rats exposed to unleaded gasoline

alpha 2u-Globulin, a protein of hepatic origin found in the urine of male rats, is accumulated in the kidney cortex during exposure to unleaded gasoline and has been implicated in the development of fuel hydrocarbon-induced nephropathy and renal neoplasia. The principal morphological feature of gasoline-induced nephropathy is accumulation of hyaline droplets (enlarged secondary lysosomes or phagolysosomes) in epithelial cells of the proximal convoluted tubule S1 and S2 segments. Inhibition of cathepsin B (a major lysosomal peptidase) by treatment of male rats with leupeptin causes rapid accumulation of phagolysosomes and alpha 2u-globulin in the kidney very similar to gasoline exposure. Further, the renal cortical subcellular distribution of alpha 2u-globulin, determined with an electron microscopic immunochemical method, is almost totally confined to phagolysosomes following administration of either gasoline or leupeptin. These results, taken together, indicate that the mechanism of nephrotoxicity of gasoline involves inhibition of renal phagolysosomal proteolysis.

Rapid postexposure decay of alpha 2u-globulin and hyaline droplets in the kidneys of gasoline-treated male rats

Unleaded gasoline induces nephropathy, characterized by rapid accumulation of hyaline (protein resorption) droplets in epithelial cells of the renal proximal convoluted tubules, only in male rats. The hepatic synthesis of the male rat-specific protein alpha 2u-globulin, a constituent of renal hyaline droplets, is unaltered by gasoline treatment (Olson et al., 1987). Renal alpha 2u-globulin content increased to 210% of control within 18 h of a single oral dose of gasoline (2.0 ml/kg); maximal levels (320% of control) were attained following gasoline administration for 3 d. Increases in renal alpha 2u-globulin caused by gasoline were accompanied by concurrent proliferation of hyaline droplets. However, within 3 d of terminating gasoline administration renal alpha 2u-globulin content decreased to the same level as that in unexposed rats, although renal hyaline droplet number returned to pretreatment levels somewhat more slowly. The conjoint effect of postexposure recovery and estradiol (an inhibitor of hepatic alpha 2u-globulin synthesis) administration was also determined in male rats. On postexposure d 3, 6, and 9, estradiol treatment (1 mg/kg, sc, 4 d, starting on d 9 of gasoline treatment) decreased renal alpha 2u-globulin content to 75%, 59%, and 48%, respectively, of that in rats allowed to recover from gasoline with no hormone treatment. Hepatic alpha 2u-globulin content in estradiol-treated rats was decreased by 74%, 97%, and 96% at the same intervals. Estradiol treatment during recovery from gasoline also appeared to increase the removal of accumulated hyaline droplets from the renal cortex. Thus, accumulation of alpha 2u-globulin-containing hyaline droplets after subacute exposure of male rats to gasoline is rapidly reversible, dependent on continuous exposure to gasoline and maintenance of the normal rate of hepatic alpha 2u-globulin synthesis. These results emphasize the dynamic state of renal cortical hyaline droplets and suggest strongly that gasoline hydrocarbons cause hyaline droplet accumulation by prolonging the half-time of degradation of alpha 2u-globulin.