Effects of acetylcholine on A and B cells of the lizard endocrine pancreas

2002 ◽  
Vol 69 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Silvana Buono ◽  
Rosalba Putti
HPB Surgery ◽  
1991 ◽  
Vol 3 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Tetsuya Hirano ◽  
Tadao Manabe ◽  
Takayoshi Tobe

To clarify the changes in pancreatic hormones and their role in the regeneration of the liver after partial hepatectomy, we measured the portal levels of insulin and pancreatic glucagon and their responses to a glucose load after about 40% hepatectomy in dogs. The changes in the A and B cells of the islets of Langerhans were examined histologically. In the early stages after hepatectomy portal insulin levels decreased significantly, and the response of portal insulin to a glucose load was lower than in the control sham-operated dogs. Both islet size and the number of B cells increased significantly after hepatectomy. Portal pancreatic glucagon levels increased significantly after hepatectomy, and the response of pancreatic glucagon to a glucose load was not suppressed. The number of A cells also increased significantly.Thus, there were differencies between insulin and pancreatic glucagon in their morphological and functional effects after hepatectomy. Although this difference is not clearly understood, there is a possibility that insulin consumption is accelerated in the remnant liver after hepatectomy. Insulin and pancreatic glucagon appear to play important but different roles in the regenerating liver from the morphological point of view.


Metabolism ◽  
1978 ◽  
Vol 27 (9) ◽  
pp. 1299-1302 ◽  
Author(s):  
Gerald J. Taborsky ◽  
Phillip H. Smith ◽  
Daniel Porte

2006 ◽  
Vol 572 (3) ◽  
pp. 691-706 ◽  
Author(s):  
Sheila Vignali ◽  
Veronika Leiss ◽  
Rosi Karl ◽  
Franz Hofmann ◽  
Andrea Welling

1972 ◽  
Vol 20 (11) ◽  
pp. 873-879 ◽  
Author(s):  
S. L. HOWELL ◽  
MARGARET WHITFIELD

A cytochemical method has been used to investigate the localization of adenyl cyclase activity in A and B cells of isolated rat islets of Langerhans. Adenosine triphosphate was initially utilized as substrate, the pyrophosphate liberated being precipitated by lead ions at its site of production. The specificity of the method was increased by the use of adenylyl-imidodiphosphate as an alternative substrate; this adenosine triphosphate analogue was not hydrolyzed by adenosine triphosphatase but provided an effective substrate for adenyl cyclase. Adenyl cyclase activity, which was found to retain its glucagon and fluoride sensitivity in glutaraldehyde-fixed tissue, was found exclusively and almost uniformly in the plasma membranes of A and B cells. Storage granule membrane, incorporated into the plasma membrane during secretion of the granule content by exocytosis, appeared to be devoid of adenyl cyclase activity.


1962 ◽  
Vol 48 (1-2) ◽  
pp. 137-141 ◽  
Author(s):  
Arne Wallgren ◽  
Bo Hellman

1971 ◽  
Vol 50 (3) ◽  
pp. 565-582 ◽  
Author(s):  
Lelio Orci ◽  
Andre E. Lambert ◽  
Yasunori Kanazawa ◽  
Mylene Amherdt ◽  
Charles Rouiller ◽  
...  

Fetal rat pancreases explanted on the 18th day of gestation and maintained in organ culture for 1–10 days were utilized for this series of studies. Ultrastructurally, at the time of explantation, the majority of fetal B cells was sparsely granulated and characterized by numerous free ribosomes and undeveloped rough endoplasmic reticulum (RER) and Golgi complexes. During the culture period, extensive development of the RER and Golgi complexes preceded an increasing accumulation of ß-granules. This later increase in the number of ß-granules and in the concentration of immunoreactive insulin was paralleled by a reduction of RER and Golgi complex activity. High resolution radioautographic studies of pulse-chase experiment over a 1 hr period demonstrated the shift of silver grains from the elements of the RER, through the Golgi region, and finally to the ß-granules. Incubation with 14C-labeled leucine demonstrated the incorporation of radioactivity into molecules possessing the immunological and electrophoretic properties of insulin. These studies indicate that de novo synthesis of (pro)insulin occurs also during culture of fetal rat pancreas explanted relatively late in gestation.


Metabolism ◽  
1976 ◽  
Vol 25 (11) ◽  
pp. 1453-1456 ◽  
Author(s):  
Daniel Porte ◽  
Phillip H. Smith ◽  
John W. Ensinck

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