Lipogenesis stimulatory and inhibitory activities of the insulin mediators

Incubating plasma membranes prepared from pig liver with varying concentrations of insulin (50-1000 microU/ml) resulted in the release of at least two insulin chemical mediators. One of them was fraction 1 of insulin mediator (M. W. 3700-4000 daltons) which had a significant lipogenesis-stimulating activity. The other was fraction 2 of insulin mediator (M. W. about 1000 daltons) which exhibited a lipogenesis-inhibitory activity. The ratio of yield between the two mediators produced from the membranes was not only dependent on the concentration but also on the potency of insulin and its analogs added. The result showed that there was more production of fraction 2 than fraction 1 with the inducer at low concentration (100 microU/ml), while the production of fraction 1 from the plasma membranes incubated with high concentration of insulin (300 microU/ml) was higher than fraction 2. On the other hand, insulin and its analogs which have different biological activities and receptor binding activities have been used to induce the insulin mediators. The results obtained were similar to those mentioned above. This suggested that the generation of the mediators was dependent on the biological potences but not the binding activities.

Interleukin-1, endotoxin or tumor necrosis factor/cachectin enhance the level of plasminogen activator inhibitor messenger RNA in bovine aortic endothelial cells

It is known that either endotoxin (LPS) or interleukin-1 (IL-1) increase the activity of plasminogen activator inhibitor (PAI) in the culture media of human and bovine endothelial cells. We have confirmed these results in bovine aortic endothelial cells (BAEC). To determine if this effect was mediated by increases in the level of PAI messenger RNA (mRNA) we examined the effects of these cytokines on PAI mRNA levels in BAEC, using RNA blot analyses. Treatment of BAEC with either IL-1, LPS, or human recombinant tumor necrosis factor/cachectin (TNF) dramatically increased the level of PAI mRNA. Since elevated levels of PAI will decrease fibrinolytic potential, this mechanism is in concert with the known increase in in vivo procoagulant potential induced by these agents and could contribute to thromboembolic phenomena.

Cloning and expression of cDNA encoding antistasin, a leech-derived protein having anti-coagulant and anti-metastatic properties

As a factor Xa inhibitor, antistasin is a potent anti-coagulant and anti-metastatic agent that is found in the salivary gland of the Mexican leech Haementaria officinalis. cDNA clones that encode antistasin have been isolated. Subsequent sequence analysis and comparison with the amino acid sequence of the mature protein indicates that antistasin is produced as a pre-protein containing a 17-amino acid signal peptide. Antistasin exists as at least two variants. By sequence analysis of multiple cDNA clones, we found two additional sites for amino acid substitutions, confirming variants that differ from each other by amino acid changes at a minimum of four residues. These sequence variations appear to be the result of allelic variation rather than gene duplication as deduced from DNA blot analyses. Sequence data suggest that antistasin may have evolved from a smaller ancestral gene by a duplication event giving rise to a two-fold structural homology between the N- and C-terminal halves of the molecule. Insect cells transfected with a recombinant baculovirus expressed antistasin which was biologically active and had an electrophoretic mobility identical to that of the native molecule.

Evolution of the genome and the genetic code: selection at the dinucleotide level by methylation and polyribonucleotide cleavage

Noting the scarcity of CpG dinucleotide in total genomic DNA derived from higher organisms and the scarcity of TpA dinucleotide in total genomic DNA derived from most life forms, we examined the distribution of these dinucleotides in sequences derived from functionally distinct types of human DNA, including mitochondrial DNA, intergenic DNA, intron DNA, and DNA destined to be represented in the cytoplasm as mRNA, tRNA, or rRNA. While CpG frequency has fallen to its lowest levels in DNA that is transcriptionally silent, TpA is most stringently excluded in DNA destined to be expressed as mRNA in the cytosol. This observation suggests that the selective pressures leading to the removal of CpG and TpA operate at different levels. With respect to TpA, dinucleotide scarcity may reflect a requirement for mRNA stability and may indicate the action of UpA-selective ribonucleases. We propose that, by reason of its instability, UpA must have been very rare in primordial RNA. Therefore, tRNA with the anticodon for this dinucleotide may have failed to evolve, making UpA the primordial doublet "stop" codon. The modern triplet code has faithfully conserved this arrangement in the two universal stop codons, UAA and UAG.

Adenylate cyclase-modulating mediators of insulin

Plasma membranes prepared from pig liver incubated with insulin (50-300 microU/ml) resulted in the release of at least two insulin chemical mediators. They appeared to modulate the activity of adenylate cyclase in liver plasma membranes of pig. One of them was fraction 1 of insulin mediator (M. W. about 3700-4000 dalton) which markedly stimulated the activity of the enzyme, the other was fraction 2 of insulin mediator (M. W. about 1000 dalton) which inhibited the enzyme activity. The results showed that the inhibitor of fraction 2 generated was significantly higher than that of fraction 1 when the membranes were incubated with insulin of low concentration (50-100 microU/ml). On the other hand, the generation of stimulator of fraction 1 from plasma membranes incubated with insulin of high concentration (200 microU/ml) was higher than that of fraction 2. So the ratio of yield between two mediators produced from the membranes was dependent on the concentration of insulin added. The results also showed that the effect of fraction 1 of insulin mediator on adenylate cyclase activity in liver cell plasma membranes was biphasic while fraction 2 of insulin mediator showed an inhibitory effect only even though it was at very high concentration. The results that both mediators combined with Gpp(NH)p and forskolin to affect the enzyme activity show that the action of insulin mediators likely resides in the GTP regulatory component of adenylate cyclase.

The role of insulin mediators in regulation of cAMP and lipogenesis as well as in diabetes

Plasma membranes prepared from pig, mouse and rat liver incubated with insulin resulted in the release of at least two insulin chemical mediators. These mediators, identified as fractions 1 and 3, were found to inhibit cAMP level in response to lipolytic hormone and forskolin and to enhance lipogenesis in adipocytes of rat. Fractions 1 and 3 have been estimated to have molecular weights of 3700-4000 and 1000-1500 dalton, respectively. This initial report will focus on fraction 1. Interestingly, liver membranes from diabetic animals were found not to release mediators in the presence of insulin. However, following in vivo treatment of diabetic animals with insulin, the liver membranes appeared to restore its ability in generating chemical mediators in response to insulin.

Menstrual blood loss, iron nutriture, and the effects of Alza-T IPCS 52, T-Cu 220C and Lippes Loop D in Korean women

The upper normal limit of menstrual blood loss (MBL) associated with iron deficiency, and the change of MBL and length of time necessary for development of iron depletion after IUD insertion in 193 healthy Korean women were studied. The mean MBL was 33.4 +or- 23.4 (SD) ml and the variation of MBL in different marital, age, and parity groups showed no statistical significance except for the higher values in young married women. Serum ferritin concentration was markedly decreased in women showing MBL above 40 ml and the frequency of subjects with serum ferritin below anemia criteria were increased in women showing MBL above 50 ml. Other parameters for assessing the iron status showed no significant difference in a different MBL range. The mean MBL in women fitted with an Alza-T IPCS 52 was significantly decreased 3 months after insertion, but the increases in hemoglobin and serum ferritin levels were statistically significant at 12 months postinsertion. The mean MBL in other IUD groups was remarkably increased at 1 month in T-Cu 220C users and between months 1-12 in Lippes Loop D users. Significant decreases in serum ferritin levels were observed at 6 and 12 months in both groups.

Isolation of full-length putative rat lysophospholipase cDNA using improved methods for mRNA isolation and cDNA cloning

We have cloned a full-length putative rat pancreatic lysophospholipase cDNA by an improved mRNA isolation method and cDNA cloning strategy. These new methods allow the construction of a cDNA library from the adult rat pancreas in which the majority of recombinant clones contained complete sequences for the corresponding mRNAs. A previously recognized but unidentified long and relatively rare cDNA clone containing the entire sequence from the cap site at the 5' end to the poly(A) tail at the 3' end of the mRNA was isolated by single-step screening of the library. The size, amino acid composition, and the activity of the protein expressed in heterologous cells strongly suggest this mRNA codes for lysophospholipase [Van den Bosch, H., Aarsman, A. J., DeJong, G. N., & Van Deenen, L. M. (1973) Biochim. Biophys. Acta 296, 94-104].

The nationwide epidemiological study of mental disorders in korea

The lifetime prevalences of DSM-III mental disorders using Korean version of DIS-III are presented. They were studied in 5,100 adults (aged 18 to 65) in household selected by two stage cluster sampling. Comparisons were made between regions, sex and age groups. International comparison with Epidemiologic Catchment Area program was also made.

Multiple transcription start sites, DNase I-hypersensitive sites, and an opposite-strand exon in the 5' region of the CHO dhfr gene

Transcription of the 26-kilobase (kb) dihydrofolate reductase (dhfr) gene in CHO cells is initiated at two sites: a major site (approximately 85% of the dhfr mRNA) at -63 relative to the translation start and a minor site (approximately 15%) at -107. Transcription also occurs from the opposite DNA strand in the dhfr 5' region, with a probable initiation site at approximately -195 relative to the dhfr translation start. A 4-kb polyadenylated RNA that is derived from the opposite-strand transcription increases threefold in abundance after serum starvation of CHO cells for 24 h. dhfr mRNA levels do not change during this time. The first dhfr exon lies within a 1-kb genomic region marked by exceptionally high G + C content and lack of DNA methylation. This region also includes a 214-base-pair (bp) exon for the opposite-strand transcript and five of the six DNase I-hypersensitive sites identified at the dhfr locus. Analysis of the DNA sequences of hamster, human (M. Chen, T. Shimada, A. D. Moulton, A. Cline, R. K. Humphries, J. Maizel, and A. W. Nienhuis, J. Biol. Chem. 259:3933-3943, 1984), and mouse (M. McGrogan, C. C. Simonsen, D. T. Smouse, P. J. Farnham, and R. T. Schimke, J. Biol. Chem. 260:2307-2314, 1985) dhfr genes reveals the presence of a 29-bp unit that is conserved 45 to 49 bp upstream of major and minor dhfr transcription start sites. This unit follows the consensus: GRGGCGGTGGCCTNNNNTGTCRCAARTRGGTR. The 5' part of the 29-bp unit contains a GC box that agrees with the GGGCGG consensus-binding site for the RNA polymerase II transcription factor Sp1 (D. Gidoni, W. A. Dynan, and R. Tjian, Nature (London) 312:409-413, 1984). Each of the three mammalian dhfr genes has several G-rich GC boxes proximal to the major dhfr transcription start site and several GC boxes of the opposite orientation (C rich) in a distal region about 500 bp upstream.

Antihypertensive activities of phenyl aminoethyl sulfides, a class of synthetic substrates for dopamine beta-hydroxylase

Four sulfur-containing analogues of phenylpropylamine were synthesized and evaluated as substrates for dopamine beta-hydroxylase (DBH) and monoamine oxidase (MAO). All four phenyl aminoethyl sulfides were shown to be good substrates for DBH whereas only the two analogues not possessing a methyl group alpha to the terminal amino group were substrates for MAO. All four analogues were tested for acute antihypertensive activity in an animal model for hypertension, the spontaneously hypertensive rat (SHR). Two of the analogues, both of which should partition readily across the blood-brain barrier, did not appreciably reduce systemic blood pressure in the 6-h testing period. However, the two analogues that were designed to be relatively restricted to peripheral sites of action caused a dramatic drop in blood pressure in SHR of 25% within 1-1.5-h postinjection, with the analogue designed to be both restricted to the periphery and MAO inactive, causing a more prolonged antihypertensive activity.

Structure and evolution of mammalian tRNA genes: sequence of a mouse tRNAiMet gene, the 5'-flanking region of which is homologous to a human gene

From a recombinant lambda phage, we have determined a 317-bp sequence containing a mouse tRNAiMet gene. The coding region is precisely homologous to mammalian tRNAiMet if post-transcriptional modifications (including addition of the 3'-terminal CCA) are not considered. The gene does not contain introns and has a typical RNA polymerase III termination site in the 3'-flanking region. It is transcribed by RNA polymerase III in the HeLa cell S-100 system in vitro. Notably, the 5'-flanking region of the mouse tRNAiMet gene shares a "patchwork" pattern of homology with one of the human tRNAiMet genes of Santos and Zasloff [Cell 23 (1981) 699-710]. The 5'-flanking regions of the two genes contain strings of nucleotides, 6 to 32 bp in length, the homology of which is 76-100%. These are separated by short strings of unrelated nucleotides. This is one of the first examples of tRNA genes containing homologous 5'-flanking regions isolated from distantly related mammals. We also report a novel method for constructing deletion mutants of sequences cloned in M13 vectors.

Screening recombinant phage M13 plaques with RNA probes; a one-step procedure which identifies clones containing either of the complementary DNA strands

We describe a method for detecting specific DNA sequences cloned in M13 phage vectors, based on the procedure of Woo (in Wu, R., Methods in Enzymology, Vol. 68, Academic Press, New York, 1979, pp. 389-395). M13 plaques are adsorbed to a nitrocellulose filter that has been pre-saturated with bacteria. The filter is incubated on an agar plate to amplify the phage; the DNA is alkali-denatured and then hybridized with a radioactive RNA probe. Unlike standard procedures, this method detects and distinguishes M13 plaques containing phage particles which harbor either the coding or non-coding (RNA-like) DNA strand, when single-stranded RNA is used as probe. We have optimized this procedure with M13 clones containing mouse histidine tRNA gene sequences and have used it to determine the sequence of both strands of a mouse glycine tRNA gene.

Effects of phenyl-2-aminoethyl sulfide, a novel dopamine-beta-hydroxylase substrate, on the cardiovascular system of the anesthetized dog

In previous work we have established that phenyl-2-aminoethyl sulfide (PAES) is a novel substrate for dopamine-beta-hydroxylase (DBH) which is stereospecifically oxygenated by the enzyme to the corresponding sulfoxide, (S)-phenyl-2-aminoethyl sulfoxide (PAESO). We now report that PAES possesses very little, if any, direct adrenergic agonist activity, but exhibits indirect sympathomimetic activity at relatively high doses (approximately 4 mg/kg). This assertion, that PAES is a new indirect sympathomimetic, is supported by our finding that pretreatment with cocaine completely abolishes the sympathomimetic activity of PAES. Furthermore, the effects of PAES are diminished with consecutive administration. In addition to its indirect sympathomimetic activity, we have also observed that PAES infusion almost completely blocks the reflex response elicited by hydralazine, a direct vasodilator. In contrast, we have found that PAESO possesses neither direct nor indirect sympathomimetic activity at doses as high as 6 mg/kg. Since PAES should be readily converted in vivo into PAESO, the implications of these findings in terms of potential antihypertensive action of PAES are discussed.

Using iodinated single-stranded M13 probes to facilitate rapid DNA sequence analysis--nucleotide sequence of a mouse lysine tRNA gene

From a recombinant lambda phage, we have determined a 387 bp sequence containing a mouse lysine tRNA gene. The putative lys tRNA (anticodon UUU) differs from rabbit liver lys tRNA at five positions. The flanking regions of the mouse gene are not generally homologous to published human and Drosophila lys tRNA genes. However, the mouse gene contains a 14 bp region comprising 13 A-T base pairs, 30-44 bp from the 5' end of the coding region. Cognate A-T rich regions are present in human and Drosophila genes. The coding region is flanked by two 11 bp direct repeats, similar to those associated with alu family sequences. The sequence was determined by a "walking" protocol that employs, as a novel feature, iodinated single-stranded M13 probes to identify M13 subclones which contain sequences partially overlapping and contiguous to an initially determined sequence. The probes can also be used to screen lambda phage and in Southern and dot blot experiments.

Isolation and nucleotide sequence of a mouse histidine tRNA gene

We have sequenced a 1307 base pair mouse genomic DNA fragment which contains a histidine tRNA gene. The sequence of the putative mouse histidine tRNA differs from the published sequence of sheep liver histidine tRNA by a single base change in the D-loop. It does not contain an unpaired 5' terminal G residue, as reported for Drosophila and sheep histidine tRNAs. The gene does not contain introns. The 3' flanking region contains a typical RNA polymerase III termination site of 6 consecutive T residues. 523 residues after the 3' end of the his tRNA coding region, the mouse DNA contains a sequence 72% homologous to part of the consensus sequence of the B1 (alu) family.

[Electrophoretic study on the changes of serum protein fractions in Korean women--the effects of age, oral contraceptive, and intrauterine contraceptive device (author's transl)]

The serum levels of total protein, albumin, and electrophoretic fractions from 610 Korean women, 21-50 years, were measured to determine their relation to age, and the effects of oral contraceptives (OCs) (Norinyl), and Lippes Loop IUD. In normal women, total protein and albumin concentrations significantly decreased with age. Alpha2 and gamma globulin concentrations were decreased after the age of 40, but the statistical significance was low. Significant decreases in total protein and albumin concentrations were observed in OC and IUD users, and rapid decrease in total protein was observed in OC users rather than in IUD users. Beta globulin was slightly increased in both groups, and gamma globulin was decreased in OC users. No significant changes in alpha1 and alpha2 globulin concentrations were noted in either group.

Isolation and partial characterization of two plasmid deoxyribonucleic acids from endosymbiotic bacteria of Amoeba proteus

Obligatory endosymbiotic bacteria in a strain of Amoeba proteus were found to harbor two distinct species of plasmid, pHJ11 and pHJ12. Their molecular weights were 39 x 10(6) and 14 x 10(6), respectively.