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Biomedical subjects

K Tsuda

Publications and source records attributed to K Tsuda.

At least 397 records · Page 22Linked to original sources
PubMed1980

Abnormal pancreatic polypeptide response to oral glucose loading diabetes mellitus.

In order to elucidate the abnormality of pancreatic polypeptide (PP) secretion in diabetes mellitus, basal plasma PP levels and their response to oral glucose loading were measured in normal subjects and diabetic patients. Fasting plasma PP levels were significantly elevated in patients with diabetes mellitus. Oral administration of 50 g of glucose elicited an exaggerated rise in plasma PP in diabetic patients as compared with the response in normal subjects. This exaggerated PP response to oral glucose loading was partially but significantly improved after the treatment, with an augmented response of plasma insulin. These results indicate the existence of abnormal PP secretion in diabetes mellitus which is probably caused by metabolic or endocrine derangements.

Adult↗
PubMed1980

Cellular synthesis and axonal transport of gamma-aminobutyric acid in a photoreceptor cell of the barnacle.

1. [3H]glutamate or [3H]gamma-aminobutyric acid (GABA) was injected into the photoreceptor cell of the lateral ocellus of Balanus eburneus, in order to study the transmitter substance of the cell. 2. The photoreceptor cell synthesized [3H]GABA from injected [3H]glutamate. 3. The newly formed [3H]GABA moved inside the photoreceptor axon towards the axon terminal with a velocity of about 0.9 mm/hr. Injected [3H]GABA moved at 0.9 mm/hr and also at 0.4 mm/hr. 4. Axonally transported [3H]GABA reached the axon terminal within several hours following the injection. It did not accumulate at the terminal, but gradually disappeared. 5. Light-microscope and electron-microscope autoradiography following the injection of [3H]GABA revealed that [3H]-reacted silver grains were present in a certain type of axon terminal. The terminal thus identified as that of a photoreceptor cell contains many clear, polymorphic synaptic vesicles about 300-500 A in diameter, some dense-cored vesicles 700-1300 A in diameter, and glycogen granules. The terminal forms many synapses, and each synapse has a synaptic dense body. The terminal always faces two post-synaptic elements at the synapse, forming a triad with a gap distance of about 160-200 A. 6. A GABA analogue, [3H]di-aminobutyric acid, was selectively taken up into the terminals previously identified as those of photoreceptors. 7. These results support the notion that the transmitter substance of the photoreceptor cell of the barnacle is GABA.

Animals↗
PubMed1980

Starvation-induced changes of somatostatin, glucagon, and insulin secretion from the isolated perfused rat pancreas.

The effect of 16- and 48-h fasting on pancreatic somatostatin, insulin, and glucagon secretion was studied, using the isolated perfused rat pancreas. In the presence of 4.4 mM glucose, basal somatostatin and insulin concentrations in the perfusate were significantly lower in 48-h fasted rats than in fed animals, whereas basal glucagon secretion was significantly elevated in fasted rats. The infusion of 19 mM arginine significantly augmented secretion of somatostatin and glucagon and attenuated insulin secretion in 48-h fasted rats. It is concluded that fasting causes a decrease in basal pancreatic somatostatin secretion in vitro, although the response to arginine is rather exaggerated. Insulin and glucagon secretion also changed during the fasting. These results suggest that not only insulin and glucagon, but also somatostatin contribute to nutrient homeostasis.

Animals↗
PubMed1980

Cerulein-induced pancreatic polypeptide secretion. Its inhibition by atropine and its possible role in regulating gallbladder relaxation.

Intramuscular administration of cerulein caused an abrupt rise in plasma pancreatic polypeptide (PP) in normal subjects. Pretreatment by atropine tended to lower the basal plasma PP level and significantly blunted the cerulein-induced PP secretion. It appears, therefore, that PP secretion induced by cerulein is under vagal control. In addition, in normal subjects, a gallbladder series first revealed a well-filled gallbladder of normal size and shape, which then contracted most strongly after a cerulein injection at a time corresponding exactly with the peak plasma PP levels produced by the cerulein. Since exogenous PP is known to cause a relaxation of the gallbladder, it is possible that endogenous PP plays an important role in gallbladder motility.

Adult↗