Concentration of mast-cell progenitors in bone marrow, spleen, and blood of mice determined by limiting dilution analysis

When hematopoietic cells of congenic +/+ mice were injected into the skin of genetically mast-cell-depleted (WB X C57BL/6)F1-W/Wv mice, mast cells appeared at the injection site. The donor origin of developing mast cells was confirmed by using giant granules of C57BL/6-bgl/bgl mice as a marker. When the number of injected cells was decreased, the proportion of injection sites at which mast cells did not appear increased according to the expected frequency of null response in a Poisson distribution. Therefore, such proportions were used to calculate the concentration of mast-cell precursors in the bone marrow, spleen, and peripheral blood. The relative concentration of mast-cell precursors in these tissues was similar to that of spleen-colony-forming cells. The present method seems useful as a semiquantitative in vivo assay for a population of progenitor cells which are committed to differentiate into mast cells.

Effect of acetylcholine and new cholinergic derivative on amylase output, insulin, glucagon, and somatostatin secretions from perfused isolated rat pancreas

The effect of infused acetylcholine and (2-acetyllactoyloxyethyl)-trimethylammonium hemi-1,5-naphthalenedisulfonate (aclatonium napadisilate), a new cholinergic drug . On endocrine and exocrine secretory responses was simultaneously investigated during the perfusion of isolated rat pancreases. Acetylcholine (1.1 microM) stimulated the output of pancreatic juice and amylase, and significantly elicited the production of both insulin and glucagon. Its effect on somatostatin secretion, however, was minimal. Both pancreatic juice flow and amylase output were also significantly stimulated by aclatonium napadisilate (12 microM). These stimulatory effects of aclatonium napadisilate on the exocrine pancreas were blocked by atropine (25 microM). Aclatonium napadisilate could stimulate glucagon, but could not influence insulin and somatostatin secretion. The addition of atropine had no effect on the release of insulin, glucagon, and somatostatin. These results indicate that the effects of aclatonium napadisilate is cholinergic, and that the action is muscarinic. In addition, it can be concluded that pancreatic somatostatin secretion, as well as other hormones from islet cells, is controlled by the parasympathetic nervous system.

Role of endocrine pancreas in temperature acclimation

Role of endocrine pancreas in temperature acclimation in rats was investigated. Plasma glucagon level increased and insulin level decreased in cold-acclimated rats (CA). The reverse was observed in heat-acclimated rats (HA). In the pancreas there were no changes in glucagon and insulin in CA, but a decrease in glucagon and an increase in insulin were found in HA. Plasma insulin/glucagon molar ratio (I/G) declined in CA and rose in HA. Pancreatic I/G rose in HA. Acute cold exposure elevated plasma glucagon, but did not effect plasma insulin. Pancreatic glucagon, insulin and I/G were not influenced by acute cold exposure, while plasma I/G decreased. Plasma I/G was inversely correlated with both blood free fatty acids and glucose levels. These results suggest that endocrine pancreas is closely associated with metabolic acclimation to cold and heat through its regulation of the metabolic direction to catabolic phase in cold acclimation and to anabolic phase in heat acclimation.

Nucleotide sequence and its character of cistron coding for the 30 K protein of tobacco mosaic virus (OM strain)

The nucleotide sequence of cloned cDNA copies of the common strain of tobacco mosaic virus RNA corresponding to the 2,000 nucleotides at the 3'-end was determined. The 30 K protein cistron was revealed to be located at residues 687-1,493 from the 3'-end. The 30 K protein is composed of 267 amino acids and is probably a basic protein. The 5' flanking regions of both the coat protein and the 30 K protein cistrons were very U-rich, and a homology was found between the sequence around the capping site of the coat protein mRNA and the sequence upstream from the 30 K protein cistron.

In vitro effect of LH-releasing factor on the content of cyclic cytidine 3' 5' monophosphate (c-CMP) in the rat anterior pituitary

The effect of LH-RF on pituitary content of cyclic cytidine 3' 5' monophosphate (c-CMP), one of the newly detected cyclic nucleotides, was examined by the RIA procedure. In results showed that the pituitary content of c-CMP was lower than in various other organs of the rat. When incubated in vitro in the presence of 0.5 ng LH-RF/ml incubation medium, c-CMP content of the anterior pituitaries was reduced slightly, but the difference was not statistically significant when compared with the controls. No difference in c-CMP content was observed between the controls and the 5 ng LH-RF/ml group. C-CMP content in the rat anterior pituitary tissue did not change significantly during an in vitro time-course study (5, 15, and 30 min.) in the presence of 5 ng LH-RF/ml. In contrast, c-AMP content of the pituitary was significantly (P less than 0.05) elevated by the stimulation of 5 ng of LH-RF/ml at a 15 minutes of incubation. These data suggest that c-CMP content, unlike c-AMP, might not be changed significantly by hypothalamic gonadotropin releasing hormone.

Thermal and metabolic responses of temperature-acclimated rats during cold and heat exposures

Some endocrine and metabolic responses to acute cold and heat exposures were observed in rats acclimated to cold, heat, or both cold and heat. Rats exposed to both cold (12 hr, 5 degrees C) and heat (12 hr, 34 degrees C) for 4 to 5 weeks (CHA) showed less fall of colonic temperature (Tc) in the cold (-5 degrees C) than heat-acclimated rats (34 degrees C, 4 to 5 weeks) (HA) and warm controls (WC), but a greater fall than cold-acclimated rats (5 degrees C, 4 to 5 weeks) (CA). CHA possessed a larger quantity of interscapular brown adipose tissue and showed greater cold-induced oxygen consumption (VO2) than WC and HA but less than CA. Blood glycerol levels rose similarly in all groups in the cold, while the increase in blood free fatty acids (FFA) levels was significantly greater in HA and smaller in CA than in WC and CHA. Acute cold exposure caused the elevation of plasma glucagon level in WC and HA, but not in CA and CHA. It lowered plasma insulin levels in HA, and the insulin/glucagon molar ratio (I/G) in WC, HA, and CHA. All groups showed the same increases in Tc during acute heat exposure (34 degrees C). However, the heat-induced increase in VO2 was greater in WC than in HA, CA, and CHA. Blood metabolite levels were not affected by acute heat exposure in all groups. Plasma glucagon levels decreased in CHA, while plasma insulin levels increased in WC and CA. I/G increased in WC and CHA. These results indicate that thermal and metabolic responses would be modified by previous exposures to cold, heat, and cold-heat.

Depolarizing IPSPs and Depolarization by GABA of rat neostriatum cells in vitro

In neostriatal slices pretreated with sodium pentobarbital (100 microM) and 4-aminopyridine (50 microM), intrastriatal stimulation elicited EPSPs followed by a slowly decaying depolarization which lasted about 200 ms and was associated with a membrane conductance increase and a suppression of spike potentials. This depolarizing inhibitory synaptic action could be blocked by picrotoxin (50 microM) or bicuculline (50 microM). The reversal potential for the slowly decaying depolarization was -57 to -62 mV, i.e. it was positive with respect to the resting membrane potential (mean = -67 mV). GABA, injected into the tissue in the vicinity of the recording electrode by pressure application, or added to the perfusate (10 microM -1 mM), depolarized the cells and reduced both the membrane resistance and the amplitude of EPSPs. The reversal potential of GABA depolarization was found in a potential range approximating that of the slowing decaying depolarization. These results are compatible with the assumption that GABA is the transmitter of an intrinsic inhibition in rat neostriatum, but indicate that GABA-mediated IPSPs of neostriatal cells in vitro are depolarizing at the resting membrane potential. The possible reasons for this are discussed.

[Effect of temperature acclimation on plasma high density lipoprotein in rats (author's transl)]

Effect of temperature acclimation to cold as well as heat on plasma high-density lipoprotein cholesterol (HDL) was investigated in rats. Cold acclimation (5 degrees C, 4 weeks) caused significant increase in plasma HDL, while heat acclimation (34 degrees C, 4 weeks) caused significant decrease in plasma HDL. Noradrenaline treatment (50 micrograms/100 g, sc., 2 times a day) did not affect plasma HDL level. These results indicate that temperature acclimation could influence HDL metabolism, possibly not via noradrenaline.

Nucleotide sequence of a cloned cDNA copy of TMV (cowpea strain) RNA, including the assembly origin, the coat protein cistron, and the 3' non-coding region

The cloned cDNA derived from the 3' end of cowpea strain (Cc) RNA of tobacco mosaic virus (TMV) has been sequenced. Substantial sequence information of 1,060 nucleotides from the 3' end of the RNA reveals some interesting features: (1) the coat protein cistron corresponds to residues 210-701 from the 3' end. Some errors in the amino acid sequence previously reported have been corrected and the revised total length of the coat protein is 162 amino acid residues. The capping site of the coat protein mRNA is at residue 711 from the 3' end of genome RNA. (2) The assembly origin of reconstitution is positioned within the coat protein cistron at residue 369-461 which can be formed into a highly base-paired hairpin loop structure. The sequence, GAXGUUG, in the loop region and a triplet-repeated purine base tract surrounding the loop are found. These structural features are common to assembly origins of both Cc and vulgare strains. (3) We find the sequence highly homologous to, but distinct from, the genuine assembly origin. It will be called the pseudo-assembly origin, which is located in the corresponding region to the assembly origin of the vulgare strain, outside the coat protein cistron. There is also the sequence, GAXGUUG, in the middle of the region. (4) In the 5' flanking region of the coat protein cistron, a long reading frame, probably of 30 K protein, is found. The coding region is terminated in the coat protein cistron and thus the 30 K protein and the coat protein cistrons overlap. (5) The 3' non-coding region is 209 residues long and can be folded into a possible tRNA-like structure. Surprisingly, we find that the 3' terminal sequence of Cc RNA is not very similar to that of vulgare RNA but extensively homologous to that of turnip yellow mosaic virus (TYMV) RNA.

Kernicterus: enzymatic evidence for difference between the development of cholinergic and GABAergic innervations in the brain of the Gunn rat

The activities of choline acetyltransferase (CAT) and glutamic acid decarboxylase (GAD), markers of cholinergic and GABAergic terminals, were measured in growing and adult Gunn rats, which possess an autosomal recessive gene for jaundice or kernicterus. In the olfactory tubercle, hippocampus, neostriatum, thalamus, and hypothalamus of the animals with kernicterus, the development of the cholinergic pathways was delayed, but by the adult stage it was normal, while there was practically no action on the innervation by GABAergic neurons, at least as indicated by the chemically measured parameters.

Studies of metabolism of tripamide, a new antihypertensive agent. II. Metabolism by the hepatic microsomal enzymes

1. The metabolism of tripamide, N-(4-aza-endo-tricyclo[5.2.1.0(2.6)]decan-4-yl)-4-chloro-3-sulphamoylbenzamide, has been studied with rat liver microsomal preparations. 2. Hydrolysis of tripamide was induced by phenobarbitone pretreatment and inhibited by O-ethyl O-p-nitrophenyl phenylphosphonothioate (EPN), a classical inhibitor of hepatic microsomal arylamidase. The hydrolysis was also catalysed by partially purified rabbit liver microsomal arylamidase. 3. The hydroxylation of tripamide was induced by 3-methylcholanthrene and inhibited by CO. 4. Inhibition of the hydroxylation of tripamide by antibodies of cytochrome P-450 and P-448 was studied. The 8-hydroxylation was inhibited by both antibodies, but 3-hydroxylation was inhibited by neither.

Spleen colony-forming cell as common precursor for tissue mast cells and granulocytes

The haematopoietic stem cells which produce colonies in the spleen of irradiated mice (CFU-S) can differentiate into erythrocytes, granulocytes, megakaryocytes and B lymphocytes. Although mast cell precursors are known to be present in the bone marrow, spleen, fetal liver and peripheral blood of mice, the relationship between the mast cell precursor and CFU-S has remained unclear. We have now made use of mice of two mutant genotypes to determine whether or not the tissue mast cell is a progeny of CFU-S. Giant granules of beige (C57BL/6-bg/bg, Chediak-Higashi syndrome) mice can be used for identification of the origin of both tissue mast cells and granulocytes, and WBB6F1-W/Wv mice are useful recipients because they lack tissue mast cells owing to a defect in mast cell precursors. We injected the cells from a single spleen colony into each WBB6F1-W/Wv mouse and demonstrated directly that the tissue mast cell is a progeny of CFU-S.

Studies on the metabolism of tripamide, a new antihypertensive agent. I. Characterization of metabolites in rats

1. Tripamide (N-(4-aza-endo-tricyclo[5.2.1.0(2,6)]decan-4-yl)-4-chloro-3-sulphamoyl [carbonyl-14C]benzamide) was metabolized in rat to yield five metabolites which were separated by chromatography, and characterized by mass spectrometry and reverse isotope dilution analysis. 2. The five metabolites were identified as follows; N-(3(or 5)-hydroxy-4-aza-endo-tricyclo[5.2.1.0(2,6)]decan-4-yl)-4-chloro-3-sulphamoylbenzamide (3-hydroxy-tripamide); N-8(or 9)-hydroxy-4-aza-endo-tricyclo[5.2.1.0(2,6)]decan-4-yl)-4-chloro-3-sulphamoylbenzamide (8-hydroxy-tripamide); 4-chloro-3-sulphamoylbenzamide; 4-chloro-3-sulphamoylbenzoic acid; and 4-chloro-3-sulphamoylbenzoic acid-(N'-acetyl)hydrazide. 3. Tripamide was metabolized rapidly and the major metabolite was 4-chloro-3-sulphamoylbenzoic acid in rat blood. 4. After intravenous injection, the excretion rate of the hydroxylated tripamide into bile was about 2-3 times faster than that into urine.