PubMed Health⌕ Search

Biomedical subjects

K Balasubramanian

Publications and source records attributed to K Balasubramanian.

At least 19 recordsLinked to original sources
PubMed1997

Regulation of porcine granulosa cell steroidogenic acute regulatory protein (StAR) by insulin-like growth factor I: synergism with follicle-stimulating hormone or protein kinase A agonist.

The transfer of cholesterol from the outer to the inner mitochondrial membrane, where side-chain cleavage occurs to form pregnenolone, is a crucial event in the regulation of steroidogenesis and recently has been demonstrated to be mediated by steroidogenic acute regulatory protein (StAR). We generated a partial porcine StAR complementary DNA (280 bp) by RT-PCR and used the corresponding antisense riboprobe to quantify the control of StAR gene expression by FSH and insulin-like growth factor I (IGF-I) in hormonally responsive swine granulosa cells, which typically manifest synergistic steroidogenic stimulation by these two dominant intrafollicular regulators. RNase protection assays were implemented to investigate the time course of the actions of FSH (100 ng/ml), IGF-I (100 ng/ml), and FSH plus IGF-I on StAR messenger RNA accumulation in serum-free cultures granulosa cells. Treatment with FSH (1.6-fold) or IGF-I (2.7-fold) alone had a small but consistent stimulatory effect on StAR message accumulation (corrected for 18S ribosomal RNA in each lane) at 48 h, whereas only IGF-I stimulated StAR protein expression (at least 6-fold as assessed by Western blot). Notably, the combined effect of FSH plus IGF-I was strongly synergistic and already significant by 24 h and maximal at 48 h (P < 0.001). Protein kinase A agonist, 8-bromoadenosine 3',5'-cAMP (8-bromo-cAMP) (1 mM) alone elicited a 3.5-fold increase in StAR message and more than 3.7-fold increase in StAR protein expression by 48 h. The combination of IGF-I and FSH or 8-bromo-cAMP evoked a 26- to 40-fold (P < 0.001) synergistic rise in StAR message accumulation. StAR protein also showed a similar synergistic pattern of expression driven by IGF-I and FSH or 8-bromo-cAMP, namely a greater than 56- to 60-fold increase. In summary, two distinct first messenger regulatory molecules, FSH and IGF-I, interact synergistically to induce amplification of StAR messenger RNA and protein expression in serum-free monolayer cultures of immature (swine) granulosa cells.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

Transbilayer phosphatidylethanolamine movements in the yeast plasma membrane. Evidence for a protein-mediated, energy-dependent mechanism.

Aminophospholipid movements in the plasma membrane of higher eukaryotic cells seem to be regulated by an ATP-dependent, protein-mediated process. To examine whether similar mechanisms exist in yeast cells, we have analysed phosphatidylethanolamine (PtdEtn) distributions in Saccharomyces cerevisiae (A184D) cells under a variety of conditions, with trinitrobenzenesulfonic acid and fluorescamine as the external membrane probes. The levels of external PtdEtn in the intact cells were reduced to about 50% by pretreatment of the cells with inhibitors of mitochondrial ATP synthesis, ATPase inhibitors or protein-sulfhydryl-group-modifying reagents, or by depletion of the cells of ATP by metabolic starvation. The levels of external PtdEtn could be restored to normal by repletion of the energy-depleted cells with ATP. Furthermore, treatment of the energy-depleted cells with sulfhydryl-modifying reagents did not cause further reduction in the external PtdEtn levels but decreased the accessibility of PtdEtn to fluorescamine after restoration of the cellular ATP levels to normal in these cells. These results demonstrate an involvement of an ATP-dependent, protein-mediated process(es) in the regulation of the PtdEtn distribution across the plasma-membrane bilayer of yeast cells. The results are discussed with regard to possible models that can generate and maintain the transbilayer phospholipid asymmetry in the yeast plasma membrane.

Adenosine Triphosphatases↗
PubMed1995

Effects of ethanol treatment on Leydig cellular NADPH-generating enzymes and lipid profiles.

Effects of ethanol treatment on Leydig cell NADPH-generating enzymes and lipid profiles were studied. Ethanol treatment (3.0 g/kg b.wt.) twice daily as a 25% (v/v) aqueous solution given to adult Wistar rats reduced the body weight, testis weight and relative weights of the seminal vesicles and ventral prostate. Serum LH and testosterone were also decreased. Similarly, the NADPH-generating enzymes such as G-6-PDH, 6-PGDH, NADP-ICDH were reduced, but malic enzyme was unaltered. Leydig cell total lipid was decreased: neutral lipids such as esterified cholesterol and triacyl glycerol were decreased but free cholesterol and diacyl glycerol were increased. The reduction in total phospholipid was contributed to by fractions such as phosphatidyl inositol, phosphatidyl serine, phosphatidyl choline and phosphatidyl ethanolamine. Withdrawal of ethanol treatment for 30 days restored these to the normal level. The present findings suggest that the ethanol treatment impairs Leydig cellular NADPH generation which may be one of the biochemical mechanisms mediating the direct and indirect effects of ethanol resulting in hypoandrogenization.

Animals↗
PubMed1995

Preliminary study of androgen, thyroid & adrenal status in alcoholic men during deaddiction.

To evaluate the status of the testes, thyroid, and adrenals in male alcoholics during the period of voluntary abstinence and therapy, chronic male drinkers undergoing a 4 wk inpatient deaddiction programme in a social hospital were recruited. Levels of a few serum and urinary hormones/metabolites viz., serum testosterone, total triiodothyronine (T3) and thyroxine (T4) and urinary total 17-ketosteroids (17-KS), estrone, estradiol, and 17-hydroxy corticosteroids (17-OHCS) were assessed in alcoholics thrice during the treatment programme at hospital i.e., on the zero (day of admission), 10th, and 20th day and compared to those of non-alcoholic controls. Alcoholics registered elevated serum total T3, and reduced total T4 and testosterone levels at admission, which persisted even after 20 days of the rehabilitative programme. Markedly high urinary levels of total 17-KS, estrone, and 17-OHCS were observed on zero day of admission. Urinary estrone and 17-OHCS, unlike total 17-KS, showed a trend to return to the normal range during the 20 days period. Urinary estradiol levels, however, recorded no significant alteration. The results of this preliminary study are suggestive of alcohol-induced perturbations on the functional integrity of the testes, thyroid, and adrenal in male alcohol addicts, wherein 20 days period of total alcohol abstinence and rehabilitative programme failed to reverse alcohol-induced hypoandrogenization and altered thyroidal status, but only partially restored certain biochemical events associated with the excretion of steroid metabolites.

17-Hydroxycorticosteroids↗
PubMed1994

Integration of graph theory and quantum chemistry for structure-activity relationships.

The objective of this article is to outline both graph-theoretically based and quantum chemically based structural indices of potential use in quantitative structure activity correlations. We consider graph-theoretical indices such as the connectivity index, topological index, Wiener index and molecular ID indices. Several structural and geometry-dependent indices can be derived from semiempirical and ab initio quantum calculations based on the charge densities, overlap matrices, frontier orbitals, molecular hardness, free valence, density matrices, quantum spectral difference indices, quantum spectral indices and bond matrices. Finally, the use of electrostatic potentials and charge densities for the prediction of reactive sites will be discussed.

Butadienes↗
PubMed1994

Ethanol induced changes in prostatic lipid profiles of albino rats.

Alcohol induced changes in the ventral and dorsolateral prostatic lipid profiles were studied. The results obtained from the present study indicate that alcohol consumption leads to significant alterations in the ventral and dorsolateral prostatic lipids. An increase in the ventral prostate total cholesterol and total glyceride glycerol was observed, but a reverse trend was seen in total phospholipid. However total lipids remained unaltered. Dorsolateral prostatic total lipids, glyceride glycerol and phospholipids were increased but a decrease in total cholesterol was observed. Withdrawal of ethanol treatment for a period of 30 days brought back most of the changes to normalcy. The abnormalities in lipid profiles of both ventral and dorsolateral prostates may be responsible for the altered semen quality prevalent in chronic alcoholics.

Alcoholism↗
PubMed1993

Effect of chronic alcoholism on semen--studies on lipid profiles.

The effect of chronic alcoholism on various seminal parameters (sperm concentration, rate of forward motility, percentage of abnormal spermatozoa, lipid profiles of seminal plasma and spermatozoa) was studied together with the serum levels of testosterone and oestradiol. In chronic alcoholics there was a marked reduction in sperm concentration and in the rate of their forward motility, and increase in the number of spermatozoa with morphological abnormalities when compared to age-matched normal fertile subjects. Serum levels of testosterone were decreased while oestradiol levels were increased in chronic alcoholic men. Studies of lipid profiles showed a marked decrease in the total phospholipid concentration in spermatozoa, primarily in sphingomyelin, phosphatidyl choline and ethanolamine fractions. The cholesterol:phospholipid ratio in spermatozoa was increased in alcoholics. In the seminal plasma of chronic alcoholics, there was a decrease in total lipid, in glyceride glycerol and in free and esterified cholesterol. Of the phospholipid classes, sphingomyelin and phosphatidyl ethanolamine showed a significant reduction. In general, the present study provides evidence for the adverse effects of chronic alcoholism on serum hormones, sperm count, morphology, motility and seminal lipid profiles. These may be responsible for the fertility disorders common in chronic alcoholics.

Alcoholism↗
PubMed1993

Specific activities of seminal vesicular phosphomonoesterases and Mg2+-,Ca2+- and Na+/K(+)-adenosine triphosphatases in hypo- and hyperthyroid albino rats.

Hypothyroidism (surgical thyroidectomy) inhibited the activities of acid phosphatase and Mg(2+)-ATPase in seminal vesicular tissue and fluid and that of Ca(2+)- and Na+/K(+)-ATPases in fluid alone, and T4 supplementation restored normalcy in all, except acid phosphatase. Hyperthyroidism (T4 25 micrograms/100g body weight/day for 60 days, im) enhanced the activities of alkaline phosphatase and ATPases in seminal vesicular tissue and fluid, and decreased acid phosphatase activity in tissue alone. Withdrawal of T4 treatment from hyperthyroid rats (after 30 days) augmented the activity of ATPases in tissue and impaired the same in fluid, while phosphomonoesterases remained at hyperthyroid level. The results suggest specific responses of various seminal vesicular phosphatases to altered thyroid hormone status. Modification in the specific threshold of androgen/estrogen action on different phosphatases in seminal vesicles appears to be the plausible mechanism underlying these changes in hypo- and hyperthyroid conditions.

Adenosine Triphosphatases↗
PubMed1993

Effects of prolactin and androgens on enzymes of carbohydrate metabolism in seminal vesicles of castrated mature bonnet monkeys, Macaca radiata.

Effects of prolactin(Prl), bromocriptine(Br), testosterone propionate (TP), dihydrotestosterone (DHT) and combinations of these androgens with Prl/Br on the maximum catalytic capacities of seminal vesicular enzymes involved in the glycolytic and pentose phosphate pathways in castrated mature monkeys were studied. Castration decreased the activities of all of the enzymes studied such as hexokinase(HK), 6-phosphofructokinase(PFK), glyceraldehyde-3-phosphate dehydrogenase(G3PD), pyruvate kinase(PK), glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase(6PGD) in the seminal vesicles. Prl restored the activities of all of the enzymes to their normal values except G3PD. TP/DHT maintained all the enzyme activities at the normal tissue intact level. Prl given along with androgens further enhanced the androgen action with regard to all the enzymes activities except G3PD. Br decreased all of the enzymes but Br with androgens maintained all the enzyme activities at the normal level. Castration decreased significantly serum T/DHT titres but Prl did not alter Prl levels. Prl+TP/DHT elevated Prl levels. Br alone decreased serum Prl, T and DHT titres, but Br+TP/DHT decreased only Prl, elevated T and maintained DHT levels. These results suggest that Prl has a direct as well as a synergistic action with androgens on the activities of the enzymes of glycolysis and pentose phosphate pathways in the seminal vesicles of castrated monkeys.

Androgens↗
PubMed1993

Primary biliary cirrhosis associated with ulcerative colitis.

Hepatobiliary diseases are frequently associated with ulcerative colitis. The most commonly reported syndromes are primary sclerosing cholangitis, chronic active hepatitis and cirrhosis. Recently, the association of primary biliary cirrhosis and ulcerative colitis has been reported. We present a case of primary biliary cirrhosis in a young man with left-sided ulcerative colitis and review the previous reported cases, noting some unique similarities between them.

Adult↗
PubMed1992

Increased intragastric acid-resistant lipase activity and lipolysis in pancreatic steatorrhoea due to cystic fibrosis.

We measured gastric lipase activity and lipolysis in postprandial gastric samples from 10 adults with steatorrhoea due to cystic fibrosis (CF) and from 10 healthy volunteers of similar age and sex. Gastric samples were aspirated for 2 h following a meal consisting of emulsified long-chain triglyceride. Mean acid-resistant lipase activity was twice as high in CF patients as in controls (596 vs. 299 nmol/ml/min fatty acid released; p = 0.028 for area under the curve). Lipolysis rose from 5 to 10% during the postprandial period in CF patients, compared with a constant 5% in controls (p = 0.036 for area under the curve). We conclude that, in healthy adults, lipolysis of long-chain triglyceride starts in the stomach, while in adults with pancreatic steatorrhoea due to CF, gastric lipase activity and intragastric lipolysis are increased, perhaps in compensation for pancreatic insufficiency.

Adult↗
PubMed1992

Therapeutic potential and clinical efficacy of acid-resistant fungal lipase in the treatment of pancreatic steatorrhoea due to cystic fibrosis.

We investigated the therapeutic potential of an acid-resistant fungal lipase prepared from Aspergillus niger. We first demonstrated in vitro that it had a wide pH optimum of 2.5-5.5 and was resistant to pepsin and trypsin. We gave the enzyme or matching placebo in random order by mouth with a fatty meal to 10 adult patients with pancreatic steatorrhoea due to cystic fibrosis (CF) and sampled gastric contents for the following 2 h. Mean acid-resistant lipase activity was 330 nmol/ml/min free fatty acid released on placebo, compared with 896 nmol/ml/min on fungal lipase (p = 0.006 for area under the curve). We compared this lipase's clinical efficacy with that of two conventional pancreatin microsphere formulations in an open randomised crossover fat-balance study in 10 similar patients. Each preparation was given for 2 weeks, and a fat-balance study, using a faecal recovery marker, was performed on the final 3 days; a period without treatment was also included. The fungal lipase had no effect on faecal wet weight or on the coefficient of fat absorption (59.0% vs. 52.3%; NS) in comparison with placebo. The established enteric-coated microsphere preparation (Creon) produced a significant reduction in faecal wet weight and improvement in coefficient of fat absorption (81.4% vs. 52.3%; p less than 0.01) in comparison with placebo. The newer microsphere preparation (Pancrex M) was also effective, but perhaps less so than Creon; there were no significant differences between the two preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Acids↗
PubMed1992

Effects of prolactin and androgens on enzymes of carbohydrate metabolism in prostate of castrated bonnet monkeys Macaca radiata (Geoffroy).

Effects of prolactin (PRL), bromocriptine (Br), testosterone propionate (TP), dihydrotestosterone (DHT) and the combinations of these androgens with PRL/Br on the specific activities of caudal and cranial prostatic cellular enzymes involved in carbohydrate metabolism in castrated mature bonnet monkeys have been studied. Castration decreased all the enzymes studied such as hexokinase (HK), 6-phosphofructokinase (6-PFK), glyceraldehyde-3-phosphate dehydrogenase (G-3-PD), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and 6-phosphogluconate dehydrogenase (6-PGD) in the cranial and caudal prostates. PRL elevated the activities of all the enzymes above normal except G-3-PD of cranial lobe. In the caudal lobe, PRL brought back the activities of HK, PFK, PK, G-6-PD to normal and 6-PGD above normal except G-3-PD. TP/DHT treatment increased all the enzymes in both the lobes. PRL given along with TP/DHT further enhanced the androgen action with regard to HK, PK, G-6-PD and 6-PGD of cranial and PFK, G-3-PD, PK, G-6-PD and 6-PGD of caudal lobe. Br treatment did not produce any alteration of these enzymes in both the lobes. In the cranial lobe, during Br+TP/DHT treatment, the stimulating effects of androgen were unaffected on all the enzymes except PK. On the other hand in the caudal, the stimulatory effects of androgens were affected and the activities of HK, PFK, PK and 6-PGD were significantly decreased. The present results suggest that PRL has a direct as well as a synergistic action with androgens on enzymes of EMP and HMP shunt in the prostates of monkeys.

Androgens↗
PubMed1992

Interaction of androgens and prolactin on prostatic enzymes of the pyruvate-malate cycle involved in lipogenesis in castrated mature monkey, Macaca radiata.

Effects of androgens, prolactin (Prl) and bromocriptine (Br) on the specific activities of prostatic (caudal and cranial) enzymes of the pyruvate-malate cycle were studied in castrated mature bonnet monkeys. Castration decreased the activity of NADP+ isocitrate dehydrogenase (ICDH), ATP citrate lyase, malate dehydrogenase (MDH), malic enzyme and fatty acid synthase (FAS). Administration of testosterone propionate (TP)/dihydrotestosterone (DHT) increased the activities of all these enzymes in both lobes. Malate dehydrogenase maintained normal activity. Prl also had a stimulatory effect on the enzymes and was further enhanced when Prl was given in combination with TP/DHT. Unlike Prl, bromocriptine treatment inhibited all the enzymes in both lobes. Thus, prolactin was found to have a direct as well as a synergistic effect with androgens on enzymes of the pyruvate-malate cycle in the prostate of castrated mature monkeys.

ATP Citrate (pro-S)-Lyase↗
PubMed1991

Effect of diabetes mellitus on epididymal enzymes of adult rats.

Diabetes mellitus caused significant reduction in serum testosterone and accessory sex glands weight. The sperm content of epididymal regions also decreased. Among the epididymal regions, the cauda epididymidal tissue alone showed significant reduction in Na(+)-K+ ATPase activity. However, Mg2+ ATPase activity was lowered in caput epididymidis only. Specific activity of Ca2+ ATPase significantly decreased in caput and cauda epididymides. All three ATPases decreased significantly in caput epididymidal spermatozoa leaving cauda epididymidal spermatozoa unaffected. Specific activity of alkaline phosphatase was suppressed in caput epididymidis and in the spermatozoa collected from caput and cauda epididymides, while the acid phosphatase was unaffected. In general, the results are suggestive of definite influence of diabetes on epididymal phosphatases which is region specific. Diabetes induced decrease in phosphatases may have an impact on secretory and absorptive functions of epididymis and thus on sperm maturation.

Acid Phosphatase↗
PubMed1991

Increased degradation of dermal collagen in diabetic rats.

The effect of alloxan induced diabetes on the dermal collagen content of albino rats was studied in relation to few lysosomal enzymes. Diabetes decreased the dermal collagen content. The specific activities of the lysosomal enzymes studied in the diabetic rat skin were elevated. It has been established that lysosomal enzymes degrade the connective tissue components. Thus, it may be suggested that the increase in the lysosomal enzymes studied should have facilitated the decrease in dermal collagen content of diabetic rats by increasing the degradation of dermal collagen.

Animals↗
PubMed1990

Effects of diethyl ether on membrane lipid ordering and on rotational dynamics of the anion exchange protein in intact human erythrocytes: correlations with anion exchange function.

The roles of lipid ordering and protein dynamics on the function of the anion exchange protein (band 3) in intact human erythrocytes have been investigated. The effects of diethyl ether on the ordering of membrane lipids and on the rotational dynamics of band 3 were measured by EPR and saturation-transfer EPR spectroscopies, respectively, and correlated with the anion exchange function of band 3. With increasing concentration, diethyl ether monotonically decreased the ordering of membrane lipids near the polar head-group region, as reported by the lipid-soluble spin probe 5-doxylstearic acid, but produced comparatively little change in the ordering of lipids in the hydrophobic midzone, as reported by 16-doxylstearic acid. The rotational mobility of band 3, as reported by the affinity spin-label bis(sulfo-N-succinimidyl) doxyl-2-spiro-5'-azelate [Anjaneyulu et al. (1989) Biochemistry 28, 6583-6590], also increased monotonically with increasing ether concentration. This increase in rotational mobility was not due to a demonstrable change in its state of oligomerization, since band 3 was readily cross-linked by bis(sulfo-N-succinimidyl) suberate to covalent dimers in the presence or absence of ether. At concentrations up to 2 vol % ether, hemolysis of erythrocytes was negligible, and the spectroscopic changes observed were completely reversed following its removal. Km, Vmax, and Eact. for sulfate uptake into chloride-loaded erythrocytes were not significantly affected by addition of ether.(ABSTRACT TRUNCATED AT 250 WORDS)

Anion Exchange Protein 1, Erythrocyte↗