Interaction of cholecystokinin and vasoactive intestinal polypeptide on function of mouse pancreatic acini in vitro.

Diastereomers of adenosine 3′,5′-phosphorothioate activate cAMP-dependent protein kinases (cAMP-PK) in vitro. We found that these compounds are highly selective tools to monitor cAMP-dependent PKA activation and its effect on amylase exocytosis from pancreatic acini. In permeabilized rat acinar cells, (Sp)-cAMPS dose-dependently stimulated amylase secretion, while (Rp)-cAMPS inhibited (Sp)-cAMPS-induced amylase release. In intact rat acini, 8-Br-(Sp)-cAMPS reduced the secretory responses to secretin, vasoactive intestinal polypeptide (VIP), 8-Br-cAMP, and 8-Br-(Sp)-cAMPS, but not to cerulein. Another derivative, dibutyryl-(Rp)-cAMPS, induced a small inhibitory effect against 8-Br-(Sp)-cAMPS and VIP, which was overlapped by an unspecific stimulatory effect on amylase exocytosis induced by the degradation product butyrate. Furthermore, (Sp)-5,6-dichloro-1-β-D-ribofuranosylbenzimidazole-3′,5′-monophosphorothioate ((Sp)-5,6-DCl-cBIMPS), a specific cAMP-PK activator, induced a maximal induction of cAMP-PK activity, but its stimulation of amylase secretion was less than that by secretin. (Sp)-5,6-DCl-cBIMPS regulated the phosphorylation of several proteins, which were also affected by secretin. However, secretin had additional effects. Its action was most likely mediated by a dual effect on the cAMP and the calcium pathway. Our results indicate that the cAMP-dependent pathway is involved in amylase exocytosis from rat pancreatic acini.Key words: secretin, vasoactive intestinal polypeptide, (Rp)-cAMPS, (Sp)-cAMPS, 8-Br-(Rp)-cAMPS, 8-Br-(Sp)-cAMPS, dibutyryl-(Rp)-cAMPS, (Sp)-5,6-DCl-cBIMPS, cAMP-dependent protein kinases, pancreatic acini, amylase secretion.

Download Full-text

Vasoactive intestinal polypeptide regulation of rabbit renal adenylate cyclase activity in vitro.

The Journal of Physiology ◽

10.1113/jphysiol.1987.sp016558 ◽

1987 ◽

Vol 387 (1) ◽

pp. 1-17 ◽

Cited By ~ 15

Author(s):

N M Griffiths ◽

N L Simmons

Keyword(s):

Adenylate Cyclase ◽

Vasoactive Intestinal Polypeptide ◽

Cyclase Activity ◽

Adenylate Cyclase Activity ◽

Intestinal Polypeptide

Download Full-text

Participation of vasoactive intestinal polypeptide in ovarian steroids production during the rat estrous cycle and in the development of estradiol valerate-induced polycystic ovary

Reproduction ◽

10.1530/rep.1.01214 ◽

2007 ◽

Vol 133 (1) ◽

pp. 147-154 ◽

Cited By ~ 16

Author(s):

Claudio Parra ◽

Jenny L Fiedler ◽

S Leticia Luna ◽

Monika Greiner ◽

Vasantha Padmanabhan ◽

...

Keyword(s):

Estrous Cycle ◽

Vasoactive Intestinal Polypeptide ◽

Polycystic Ovary ◽

Secretory Activity ◽

Estradiol Valerate ◽

Steroid Secretion ◽

Cyclic Changes ◽

Intestinal Polypeptide

Vasoactive intestinal polypeptide (VIP) stimulates estradiol and progesterone release from ovarian granulosa cells in vitro. Very little information is available as to the role VIP plays in the control of steroid secretion during reproductive cyclicity and in ovarian pathologies involving altered steroid secretion. In this study, we determined the involvement of VIP in regulating ovarian androgen and estradiol release during estrous cyclicity and estradiol valerate (EV)-induced polycystic ovarian development in rats. Our findings show that androgen and estradiol release from ovaries obtained during different stages of rat estrous cycle mimic cyclic changes in steroid release observed in vivo with maximal release occurring during late proestrus. VIP increased androgen release from ovaries of all cycle stages except late proestrus and estradiol release from all cycle stages. Increases in VIP-induced androgen and estradiol release were maximal at early proestrus. Inclusion of saturating concentrations of androstenedione increased magnitude of VIP-induced estradiol release at diestrus and estrus but not proestrus. Magnitude of VIP-induced androgen and estradiol release tended to be greater in the ovaries from EV-treated rats with polycystic ovary compared with estrous controls. At the tissue level, ovarian VIP concentration was cycle stage dependent with highest level seen in diestrus. Maximum concentration of VIP was found in EV-treated rats. Changes in VIP were inversely related to changes in ovarian nerve growth factor, a neuropeptide involved in ovarian androgen secretion. These results strongly suggest that intraovarian VIP participates in the control of estradiol secretion during the rat estrous cycle and possibly in the maintenance of increased ovarian estradiol secretory activity of EV-treated rats.

Download Full-text

Reversal of nerve damage in streptozotocin-diabetic rats by acute application of insulin in vitro

Clinical Science ◽

10.1042/cs0750629 ◽

1988 ◽

Vol 75 (6) ◽

pp. 629-635 ◽

Cited By ~ 23

Author(s):

Geoffrey Burnstock ◽

Rhona Mirsky ◽

Abebech Belai

Keyword(s):

Vasoactive Intestinal Polypeptide ◽

Calcitonin Gene Related Peptide ◽

Diabetic Rats ◽

Diabetic Rat ◽

Rat Ileum ◽

Related Peptide ◽

Calcitonin Gene ◽

Enteric Nerves ◽

Intestinal Polypeptide

1. Immunohistochemical, immunoblotting and release experiments were performed on ileum from control rats, from 8-week streptozotocin-diabetic rats and from diabetic rats after acute application of insulin in vitro. 2. There was an increase in vasoactive-intestinal-polypeptide-like and a decrease in calcitonin-gene-related-peptide-like immunoreactivity in the myenteric plexus of the diabetic rat ileum, although electrically evoked release of both peptides from enteric nerves was defective. Acute application of insulin in vitro reversed the defective release and changes in immunoreactivity of vasoactive intestinal polypeptide and calcitonin-gene-related peptide seen in the enteric nerves of streptozotocin-diabetic rat ileum. 3. In addition, using a monoclonal neurofilament antibody RT 97 that recognizes a phosphorylated neurofilament epitope present in normal enteric nerves, it was shown that this phosphorylated neurofilament epitope was absent in diabetic nerves, even though a polyclonal neurofilament antibody revealed that neurofilaments were present in both axons and cell bodies of the myenteric plexus of diabetic rat ileum. After only 2 h of insulin incubation in vitro, the phosphorylated neurofilament epitope was again present in the nerves. 4. It is suggested that the abnormal distribution of phosphorylated neurofilaments and defective storage and release of vasoactive intestinal polypeptide and calcitonin-gene-related peptide in the present study may be a more general feature of diabetes. The restoration of these abnormalities by continuous acute insulin application in vitro shown here suggests that the availability of a steady level of insulin might prevent some of the changes which occur in early stages of diabetes. If so, this could influence the use of insulin in the treatment of diabetes, particularly in view of the recent report that short-term continuous subcutaneous insulin infusion restores the function of the autonomic and peripheral nerves in type I diabetic patients [Krönert, K., Hülsen, J., Luft, D., Stetter, T. & Eggstein, M. (1987) Journal of Clinical Endocrinology and Metabolism, 64, 1219–1223].

Download Full-text