Effect of various catecholamine antagonists on prolactin secretion in conscious male rabbits

To clarify physiological roles of catecholaminergic systems in the control of rabbit prolactin (PRL) release, the effect of various catecholamine receptor antagonists on plasma PRL levels was examined in conscious, freely moving male rabbits. An intravenous (iv) injection of yohimbin (2.5 mg/kg body wt), an alpha 2-adrenoreceptor antagonist, but not prazosin (2 mg/kg body wt), an alpha 1-adrenergic receptor antagonist, resulted in a significant elevation of plasma PRL. Conversely, propranolol (2.5 mg/kg body wt, iv), a nonselective beta-adrenoreceptor antagonist, and metoprolol (2.6 mg/kg body wt, iv), a beta 1-adrenergic antagonist, slightly but significantly suppressed basal levels of plasma PRL. On the other hand, haloperidol (0.5 mg/kg body wt, iv), pimozide (0.3 mg/kg body wt, iv), sulpiride (5 mg/kg body wt, iv), chlorpromazine (3 mg/kg body wt, iv), and YM-09151-2 (0.2 mg/kg body wt, iv), all dopamine receptor antagonists caused a significant increase in plasma PRL. These results suggest that dopaminergic and alpha 2-adrenergic mechanisms exert a tonic inhibitory role and beta-adrenergic mechanisms, probably beta 1, a tonic stimulatory role in the regulation of PRL release in the rabbit.     

Selective enhancement in striatal [H]nitrendipine binding following chronic treatment with morphine

Two parameters of Ca²⁺ dynamics in brain preparations (⁴⁵Ca-uptake to slices and [³H]nitrendipine binding to membrane fractions) were measured in naive and chronic morphine-administered rats. While morphine did not have any effect on ⁴⁵Ca-uptake to striatal slices in normal Krebs-Ringer solution, it inhibited K⁺-stimulated ⁴⁵Ca-uptake to slices. Furthermore, the effect of morphine was antagonized by naloxone. Inhibition of K⁺-stimulated ⁴⁵Ca-uptake to striatal slices by morphine was not observed in preparations obtained from chronic morphine-administered rats (6 mg/kg/b.i.d./7 days). In membrane fractions, [³H]nitrendipine binding increased by 34% in striatum following chronic morphine treatment, whereas no change was observed in the cortex and hippocampus. The results will be discussed in relation to the phenomena underlying chronic morphine administration.     

Accumulation of ornithine decarboxylase-antizyme complex in HMOA cells.

A new method was developed for the assay of ornithine decarboxylase (ODC)-antizyme complex, in which alpha-difluoromethylornithine (DFMO)-inactivated ODC was used to release active ODC competitively from the complex. ODC-antizyme complex was present in the extracts of hepatoma tissue-culture (HTC) cells and of ODC-stabilized variant HMOA cells, in much larger amounts in the latter. Cellular amounts of the complex fluctuated after a change of medium in a similar manner in HTC and HMOA cells, increasing during the period of ODC decay. After treatment with cycloheximide, the decay of ODC-antizyme complex in HMOA cells was more rapid than the decay of free ODC, but it was much slower than the decay of free ODC or complexed ODC in HTC cells. Administration of putrescine caused a rapid increase in the amount of ODC-antizyme complex in both HTC and HMOA cells, but nevertheless the decay of total ODC (free ODC plus ODC-antizyme complex) was more rapid with putrescine than with cycloheximide. These results suggested the possibility that ODC is degraded through complex-formation with antizyme. In contrast with complexed antizyme, free antizyme was not stabilized in HMOA cells.     

Human cellular src gene: nucleotide sequence and derived amino acid sequence of the region coding for the carboxy-terminal two-thirds of pp60c-src.

The nucleotide sequence of the 3' two-thirds of a highly conserved, molecularly cloned human cellular src gene (c-src) has been determined. This region of the c-src gene encodes the tyrosine kinase domain of the cellular src protein (pp60c-src) and corresponds to exons 6 through 12 of the chicken c-src gene, as well as nucleotides 545 to 1542 of the Rous sarcoma virus src gene (v-src). The human c-src sequence is very strongly conserved with respect to both the chicken c-src and the Rous sarcoma virus v-src genes, with nearly 90% nucleotide homology observed in this region. Amino acid sequence conservation in this region is even greater; 98% of the amino acids are conserved between human and chicken c-src. Furthermore, the exon sizes and the locations of the exon-intron boundaries are identical in the human and chicken c-src genes. However, sequences within the introns have not been conserved, and the introns within the human c-src gene are significantly larger than the corresponding introns within the chicken c-src gene. The strong amino acid conservation between the carboxy-terminal two-thirds of pp60c-src of species as divergent as humans and chickens suggests that this portion of the pp60c-src protein specifies one or more functional domains that are of great importance to some aspect of normal cellular growth or differentiation.     

Electrophoretic variants of blood proteins in Japanese. IV. Prevalence and enzymologic characteristics of glucose-6-phosphate dehydrogenase variants in Hiroshima and Nagasaki

Summary Electrophoretic screening of glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6PD) was conducted one sample of 9,260 children born to the atomic bomb survivors in Hiroshima (Honshu) and Nagasaki (Kyushu). The prevalence of electrophoretic variants was 0.11% in males and 0.42% in females in Hiroshima, and 0.16% in males and 0.31% in females in Nagasaki. Enzymologic characteristics of 10 variants obtained from three males and seven hemizygous fathers of heterozygous females were examined. As a result, three new types of G6PD variants were identified among five variants detected in Hiroshima, and three new types among five variants in Nagasaki. All the variants except one belonged to Class 3, as defined by Yoshida et al. (1971).     

Morphological aspects on pancreatic islets of non-obese diabetic (NOD) mice

The pancreatic islets of female non-obese diabetic (NOD) mice (a model of insulin-dependent diabetes mellitus), have been examined by both light and electron microscopy. At about the age of 2 weeks, mononuclear cells began to infiltrate in or near the islets and some of these cells were in contact with the islet cells. Following this degeneration of islet B-cells took place, the process occurring in two ways. In many cells numerous secretory granules with extremely dense cores occupied the cytoplasm. Other cells, however, were filled with low-density secretory granules and the nuclei of these cells became pycnotic. After degeneration of B-cells, the islets were effaced by numerous mononuclear cells. With the onset of the diabetic state these mononuclear cells gradually disappeared, and thereafter small islets remained. By electron microscopy, retrovirus-like particles were observed in cisternae of the rough endoplasmic reticulum in islet B-cells at all stages. With an anti-retrovirus serum (goat anti-KiMSV-NIHxeno serum), positive immunofluorescence was observed in some pancreatic islet cells of NOD mice aged 1 day and 4, 6, 8, 9, 10 and 14 weeks. It is suggested that these virus particles may be intimately related to the inflammatory reaction occurring in the islets and to the development of diabetes mellitus.     

A highly purified allergen from excretory and secretory products of Dirofilaria immitis

Preceding data revealed that the allergen concentrated mainly in excretory and secretory (ES) products exhausted by adult Dirofilaria immitis. The present paper reported that a highly purified allergen was obtainable from ES products more easily and effectively. An allergen in ES products was purified by a combination of DEAE-Sephadex A-50 chromatography, Sephadex G-200 and Sephadex G-100 gel filtration. The purified preparation was proved to be one protein by sodium dodecyl sulfate (SDS) gel electrophoresis and to be exact the same allergen with the one obtained from the crude extract of adult Dirofilaria worms. The molecular weight of the purified allergen was estimated to be 15,000, and the allergen was inclined to aggregate in the buffered solution.     

Genetic analysis of three additional fla genes in Salmonella typhimurium

In Salmonella typhimurium, 27 fla genes responsible for formation of flagella have been identified and assigned to three regions on the genetic map, termed fla regions I to III. By genetic analysis of 1984 non-flagellate mutants obtained from a phase-1 stable strain of S. typhimurium, SJW1103, three additional fla genes were identified; one, termed flaW, was assigned to fla region I and the other two, termed flaV and flaX, to fla region III. By intergeneric complementation tests, the flaW, flaV and flaX genes were shown to be functionally homologous with flaS, flbC and flaP of Escherichia coli, respectively. Electron microscopy showed that flaW and flaV mutants carried hook-basal body structures.     

Genetic analysis of H2, the structural gene for phase-2 flagellin in Salmonella

Non-flagellate H2 mutants were isolated from a phase-2 stable strain, SJW806 H1-gt- H2-enxon vh2-, a derivative of Salmonella typhimurium. By transductional crosses a deletion map and a recombination map of the H2 gene were made. There are three regions especially rich in nonflagellate mutational sites. By the use of the deletion map, mutational sites of 21 flagellar shape mutants were also determined. Most of them were located at two regions which coincide with two of the three regions rich in non-flagellate mutational sites. A gene, vh2, is closely linked to the promoter side of the H2 gene. Three-factor transductional crosses showed that the vh2 gene was on the left of the H2 gene in the present map. The H2 gene forms part of an operon with the distal gene rh1 which specifies the H1 repressor. Thus, a polarity effect of the H2 mutations on the expression of the rh1 gene was examined by observing whether a wild-type H1 allele introduced into the H2 mutants was expressed or not. Many of the H2 mutations were polar, and most of the strongly polar mutations were located in the left (promoter-proximal) half of the H2 gene, while most of the mutations in the right half of the gene were weakly polar or non-polar.