ABSTRACT
Calcitonin biosynthesis has been studied in chicken ultimobranchial glands incubated in vitro in the presence of radioactive amino acids. The results obtained suggest the existence of a biosynthetic precursor of higher molecular weight or procalcitonin. This precursor has been identified by pulse-chase experiments, molecular weight determinations, biological activity measurements and analysis of tryptic peptides. Its molecular weight is about 13000 (calcitonin, about 3500) as determined by polyacrylamide gel electrophoresis. Procalcitonin is present in small amounts in chicken ultimobranchial glands and it is biologically active in rats.
Subject(s)
Calcitonin/biosynthesis , Ultimobranchial Body/metabolism , Animals , Biological Assay , Calcitonin/isolation & purification , Chickens , In Vitro Techniques , Kinetics , Male , Molecular Weight , Peptide Fragments/analysis , Rats , TrypsinSubject(s)
Calcitonin/metabolism , Chickens/metabolism , Ultimobranchial Body/metabolism , Animals , Bucladesine/pharmacology , Calcitonin/biosynthesis , Calcitonin/isolation & purification , Calcium/pharmacology , Chromatography, Gel , Electrophoresis, Disc , In Vitro Techniques , Leucine/metabolism , Stimulation, Chemical , Time Factors , TritiumSubject(s)
Calcitonin/analysis , Ultimobranchial Body/analysis , Amino Acid Sequence , Amino Acids/analysis , Animals , Biological Assay , Calcitonin/isolation & purification , Calcitonin/pharmacology , Chickens , Chromatography, Gel , Chromatography, Ion Exchange , Chromatography, Thin Layer , Dansyl Compounds , Electrophoresis, Disc , Hypocalcemia/blood , Male , Rats , Salmon , Species Specificity , Spectrophotometry, Ultraviolet , Swine , Time FactorsSubject(s)
Dicumarol/pharmacology , Extracellular Space/drug effects , Hypoxia/metabolism , Insulin/pharmacology , Muscles/metabolism , Animals , Carbohydrates/analysis , Carbon Isotopes , Diaphragm/drug effects , Diaphragm/metabolism , Female , In Vitro Techniques , Male , Muscles/analysis , Muscles/drug effects , Organ Size , Oxygen Consumption/drug effects , Photometry , Rats , Sorbitol/analysis , Time Factors , Vitamin K/pharmacology , Water/analysis , Xylose/analysisSubject(s)
Dicumarol/pharmacology , Hypoxia/metabolism , Insulin/pharmacology , Monosaccharides/metabolism , Muscles/metabolism , Animals , Carbohydrates/analysis , Carbon Isotopes , Diaphragm/drug effects , Diaphragm/metabolism , Extracellular Space/metabolism , Female , Fructose/metabolism , Galactose/metabolism , Glucose/metabolism , Hexoses/metabolism , In Vitro Techniques , Male , Muscles/drug effects , Pentoses/metabolism , Rats , Time Factors , Xylose/metabolismSubject(s)
Glycogen/biosynthesis , Ostreidae/metabolism , Animals , Carbon Isotopes , Fructose/metabolism , Gills/metabolism , Glucose/metabolism , Glycerol/metabolism , Glycogen/analysis , Glycogen/isolation & purification , Hydroxybutyrates/metabolism , In Vitro Techniques , Kinetics , Leucine/metabolism , Oxygen Consumption , Potassium/metabolism , Pyruvates/metabolism , Time Factors , Trehalose/metabolismSubject(s)
Bacterial Proteins/biosynthesis , Escherichia coli/metabolism , Galactosidases/biosynthesis , Glucagon/pharmacology , RNA, Bacterial/biosynthesis , Cyclic AMP/pharmacology , Electrophoresis, Starch Gel , Escherichia coli/drug effects , Escherichia coli/enzymology , Leucine/metabolism , Mutation , RNA, Bacterial/analysis , Spheroplasts/metabolism , Uridine/metabolismSubject(s)
Pancreas/cytology , Animals , Cell Nucleus , Chromaffin System/cytology , Cytoplasmic Granules , Microscopy, Electron , Mitochondria , Rabbits , RibosomesSubject(s)
Insulin/metabolism , Pancreas/metabolism , Animals , Culture Media , Culture Techniques , Ducks , Insulin SecretionABSTRACT
The cytological changes observed in the A and D cells of rabbit endocrine pancreas incubated in a medium containing 0.6 mg/ml or 3 mg/ml of glucose are described. These cells showed no changes in their fine structure nor any signs of degranulation. When the A cells were incubated in a medium without glucose, they released A granules and synthesized new hormone. The way in which A granules are eliminated is compared to that following insulinic hypoglycemia in the animal in vivo. In both cases, the mechanism of secretion involves margination, emiocytosis of the entire granule, and formation of microvilli, in contrast to previously reported observations (9). The D cells showed no alteration of their fine structure after incubation with different concentrations of glucose in the medium. Only very rarely could we observe morphological changes which were suggestive of emiocytosis of the entire D granule.
