Mitochondrial hinge protein is a subunit of ubiquinol-cytochrome-c reductase in the respiratory chain and 'hinges' cytochrome c with cytochrome c1. The protein is encoded in the nuclear genome, synthesized in the cytosol and then imported into the mitochondria. The cDNA of the human hinge protein has been cloned and its nucleotide sequence was determined. The deduced primary structure of the amino-terminal presequence consists of 13 amino acid residues, of which 4 amino acids are acidic and only one is basic. Since the presequences of most other precursors are rich in basic amino acids, this sequence is unique for targeting mitochondria. Expression of the gene was repressed in the presence of a phorbol ester in human promyelocyticleukemia cells (HL-60), and this repression was greater than that of the ADP/ATP translocator. These findings suggest that the hinge protein, the expression of which is well regulated, is imported into mitochondria via a specific pathway.

Amino Acid Sequence↗

PubMed1987

[CT of blow-out fracture of the orbit].

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Adolescent↗

PubMed1987

Vasodilating effects of human and rat calcitonin gene-related peptides in isolated porcine coronary arteries.

Human and rat alpha-calcitonin gene-related peptides (CGRPs) caused relaxation of porcine coronary arterial strips precontracted by 10(-5) M of prostaglandin (PG) F2 alpha at low concentrations. pD2 values for human and rat CGRPs in endothelium-preserved strips were 8.41 +/- 0.03 (n = 5) and 8.49 +/- 0.03 (n = 5), respectively. The same concentrations of CGRPs relaxed the endothelium-depleted preparations. CGRPs were much more potent and had steeper concentration-response curves than isoproterenol, nitroglycerin (GTN), isobutylmethylxanthine (IBMX), verapamil and nifedipine. Like isoproterenol, GTN and IBMX, but in contrast to the calcium antagonists, the relaxing potencies of human and rat CGRPs were greatly reduced in the strips precontracted by 50 mM of KCl. The relaxation caused by human CGRP was not affected by treatment with propranolol (10(-6) M) or cimetidine (10(-5) M). Human CGRP (1.6 X 10(-8) M) caused a significant (about 2-fold) elevation of the content of cyclic AMP in coronary tissue but did not cause any change in the content of cyclic GMP. CGRP-like immunoreactive fibers were found to be localized in the adventitia but not in the media or intima of the coronary artery. These results indicate a direct and endothelium-independent potent relaxant action of CGRP in coronary vessels. This relaxation could be caused by a mechanism not shared by calcium antagonists but associated with the rise in cyclic AMP.

Animals↗

PubMed1987

Plasma progesterone profiles and embryo quality in superovulated Japanese Black cattle.

The relationship between plasma progesterone (P(4)) levels before and after superovulation treatment and embryo yield and quality was examined in Japanese Black cattle. It is concluded that a plasma P(4) level at the start of follicle stimulating hormone (FSH) injections is related to embryo quality. The P(4) level of over 3.0 ng/ml appears to be useful in preselection of donors when we want to get more than 8 normal (transferable) embryos on the average.

Journal Article↗

PubMed1987

Isolation and amino acid sequence of calcitonin gene related peptide from porcine spinal cord.

Porcine calcitonin gene related peptide (pCGRP) was isolated from spinal cord by HPLC combined with bioassays using the rat vas deferens and the rat heart. The amino acid sequence was determined by microsequencing methods to be; S-C-N-T-A-T-C-V-T-H-R-L-A-G-L-L-S-R-S-G-G-M-V-K-S-N-F-V-P-T-D-V-G-S-E-A- F-NH2. The structure determined was found to be more similar to that of the second human CGRP (beta-CGRP) than that of the first human CGRP (alpha-CGRP). Of the spinal cord peptides, only pCGRP showed strong relaxant activity on the electrically induced contraction of the rat vas deferens and strong enhancing effect on the rat heart rate.

Amino Acid Sequence↗

PubMed1987

Effects of calcitonin gene-related peptide (CGRP) and isoproterenol on the contractility and adenylate cyclase activity in the rat heart.

The occurrence of calcitonin gene-related peptide (CGRP) has been predicted by the study of the calcitonin gene of rats [1]. Recently CGRP was isolated from porcine spinal cord [3], and thus, CGRP is assumed to be a neuropeptide. It has been shown that CGRP exhibits potent positive chronotropic and inotropic effects on the atrial muscles of rats and guinea-pigs [5, 9, 11] . We have previously demonstrated the presence of nonadrenergic noncholinergic (NANC) nerves in the atria of rats and guinea-pigs [10] and have suggested that CGRP is a neurotransmitter of the NANC nerves in the guinea-pig atria [9, 11]. It is supposed that the positive inotropic response mediated by the beta-adrenoceptor results from a stimulation of the adenylate cyclase (AC) activity and subsequent elevation of cyclic AMP (cAMP) content. In the present study, the effects of calcitonin gene-related peptide (CGRP) and isoproterenol (ISO) on the myocardial contractility and adenylate cyclase (AC) activity were compared in cardiac muscles of the rat. In atrial muscles, CGRP exerted a positive inotropic effect and stimulated the AC activity at the similar dose range. On the contrary, the concentrations of ISO needed to stimulate the AC activity were nearly 10-fold higher than those needed for eliciting positive inotropic responses. In ventricular muscles, CGRP produced neither a positive inotropic responses nor a stimulation of AC activity, while ISO induced both responses. Inasmuch as CGRP-like immunoreactive (CGRP-I) nerves were found to be present in the atria but rarely in the ventricles, CGRP was assumed to be physiologically important in the atria rather than in the ventricles.

Adenylyl Cyclases↗

PubMed1987

Preparation and characterization of the major isotype of parvalbumin from skeletal muscle of the toad (Bufo bufo japonicus).

The major isotype of parvalbumin has been isolated from the skeletal muscle of the toad, Bufo bufo japonicus. Unlike the skeletal muscle of every frog so far examined (Rana esculenta, Rana temporaria, and Rana catesbeiana), which contains two major isotypes of parvalbumins, toad skeletal muscle has been shown to contain only one isotype, but the content of parvalbumin in toad skeletal muscle was similar to the sum of those of the two isotypes in skeletal muscles of frogs. This feature of toad skeletal muscle is advantageous to clarify the physiological role of parvalbumin. The relative molecular mass of toad parvalbumin was estimated to be 12,200 by SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to be 4.81 by polyacrylamide gel isoelectric focusing. The amino acid composition indicated that toad parvalbumin corresponds to bullfrog (R. catesbeiana) pI 4.97 parvalbumin, showing that toad parvalbumin is genetically an alpha-parvalbumin. It was also revealed by the amino acid composition that toad parvalbumin is distinctly different from any of the parvalbumins from frogs. The ultraviolet spectrum of toad parvalbumin is consistent with its amino acid composition. The ultraviolet difference spectrum of the Ca2+-loaded form vs. the metal-free form indicates that some Phe residues in the toad parvalbumin molecule are affected by a conformational change associated with Ca2+ binding. On electrophoresis in polyacrylamide gel in 14 mM Tris and 90 mM glycine, the metal-free and Mg2+-loaded forms of toad parvalbumin migrated twice as fast as the Ca2+-loaded form.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1987

Effects of capsaicin on nonadrenergic noncholinergic nerves in the guinea pig atria: role of calcitonin gene-related peptide as cardiac neurotransmitter.

Transmural nerve stimulation (TNS) in vitro produced positive chronotropic and inotropic responses in the spontaneously beating right atria and electrically driven left atria of guinea pigs, respectively. Both the positive responses of the atria were mediated not only by adrenergic but also by nonadrenergic noncholinergic (NANC) nerves. Numerous calcitonin gene-related peptide (CGRP)-like immunoreactive nerves were found in the sinus node and the muscle layers of both atria of guinea pigs. Exogenously applied CGRP produced positive chronotropic and inotropic responses in a dose-dependent manner. In both the right and left atria, capsaicin (10(-5) M) induced positive chronotropic and inotropic responses. The second application of capsaicin did not cause any responses in the atria, indicating a rapid development of tachyphylaxis. When the tissues developed tachyphylaxis to capsaicin, the intensity of CGRP-like immunoreactivity greatly decreased in the sinus node and in both atria. In the atria that developed tachyphylaxis to capsaicin, the positive chronotropic and inotropic responses to NANC nerve stimulation diminished markedly, but the responses to exogenous CGRP and those attributed to adrenergic nerves were not affected. These results suggest that CGRP is the neurotransmitter of intracardiac NANC nerves and that capsaicin produces positive chronotropic and inotropic responses through the release of CGRP from NANC nerves in the guinea pig atria. It is also suggested that capsaicin depletes endogenous CGRP, thereby accounting for the rapid development of tachyphylaxis to capsaicin and the marked and selective diminution of TNS-induced NANC responses following application of capsaicin.

Animals↗

PubMed1987

Lens-specific enhancer in the third intron regulates expression of the chicken delta 1-crystallin gene.

We have previously shown that the tissue specificity determinant of the chicken delta 1-crystallin gene lies 3' of position -100 (Hayashi et al. 1985). Since the promoter of the gene (delta 1-crystallin promoter) did not show any tissue specificity, we examined various segments of the delta 1-crystallin gene for a tissue-specific enhancer activity by placing each segment downstream of a heterologous transcriptional unit coding for chloramphenicol acetyltransferase (CAT) and by transfecting chicken tissues in primary culture. We found that a segment spanning the third intron bears a strong lens-specific enhancer activity. This "delta 1-crystallin enhancer" activates transcription from the delta 1-crystallin promoter 20- to 40-fold in lens cells and to various degrees with other promoters. Deletion analysis of the enhancer region indicated that it covered nearly 1 kb but did not indicate clear-cut boundaries. For its enhancer effect the core region of 120 bp and associations with certain adjoining regions were required. Removal of the enhancer from the gene totally abolished delta 1-crystallin expression, and reinsertion of the enhancer in either upstream, internal, or downstream positions restored expression. We conclude that the delta 1-crystallin enhancer is an essential and major determinant for lens-specificity of delta 1-crystallin expression.

Animals↗

PubMed1987