scholarly journals In Vitro Insulin Release from Thermosensitive Chitosan Hydrogel

2012 ◽  
Vol 13 (2) ◽  
pp. 460-466 ◽  
Author(s):  
Elham Khodaverdi ◽  
Mohsen Tafaghodi ◽  
Fariba Ganji ◽  
Khalil Abnoos ◽  
Hanie Naghizadeh
Keyword(s):  
Insulin Release ◽  
Chitosan Hydrogel ◽  
In Vitro Insulin Release

pH Responsive Polymeric Nanoparticles for Oral Insulin Delivery

2017 ◽  
pp. 6-10
Author(s):  
Charu Tyagi
Keyword(s):  
Insulin Release ◽  
Polymeric Nanoparticles ◽  
Attenuated Total Reflectance ◽  
Ph Responsive ◽  
Eudragit L100 ◽  
Release Studies ◽  
Mean Size ◽  
The Mean ◽  
In Vitro Insulin Release

Gelatin-eudragit L100 nanoparticles of wet size range 170-563nm were prepared by two step dissolvation method and the effect of different concentrations of eudragit L100 and emulsifying agent - sodium lauryl sulphate (SLS) - on the particle size were studied. Synthesized nanoparticles were characterized by attenuated total reflectance-fourier transform infrared spectroscopy (ATRFTIR) and the mean size distribution. Insulin loading was done at a pH 7.4 and the in vitro insulin release studies of nanoparticles were carried out by simulating gastrointestinal tract condition which showed the minimal insulin release at pH 2.5 (20% in 90min) while appreciable release (40% in first 30min) at pH of 7.4. This pH responsive release pattern of the synthesized nanoparticles confers on the insulin protection from proteolytic degradation in acidic environment of stomach and upper intestinal part while enhancing bioavailability in the later part of intestine.

Regulation of in Vitro Insulin Release from a Transplantable Syrian Hamster Insulinoma1

Endocrinology ◽  
1975 ◽  
Vol 97 (2) ◽  
pp. 442-447 ◽  
Author(s):  
SHELLEY SHAPIRO ◽  
SUMIYA ETO ◽  
NORMAN FLEISCHER ◽  
STEPHEN G. BAUM
Keyword(s):  
Insulin Release ◽  
Syrian Hamster ◽  
In Vitro Insulin Release

scholarly journals Insulin Release from NPH Insulin-Loaded Pluronic® F127 Hydrogel in the Presence of Simulated Tissue Enzyme Activity

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1320
Author(s):  
Muhammad H. Sultan ◽  
Wael A. Mahdi ◽  
Young M. Kwon
Keyword(s):  
Enzyme Activity ◽  
Insulin Release ◽  
Burst Release ◽  
Nph Insulin ◽  
Native Form ◽  
Gelling Temperature ◽  
History Of ◽  
History Of Use ◽  
In Vitro Insulin Release

Background: Despite the widespread use of newer basal insulins, Natural Protamine Hagedorn (NPH) insulin still represents a well-established basal formulation with its long history of use, featuring the native form of human insulin. However, NPH insulin exhibits an undesirable peak within hours after a single subcutaneous (s.c.) injection, which may lead to hypoglycemia followed by insufficient basal insulin delivery. This may be attributed to the s.c. enzyme activities degrading the protamine in NPH microcrystals. Methods: A thermogelling block copolymer Pluronic® F127 (PF127) was utilized as a protective carrier for NPH microcrystals and as a modulator for insulin release from NPH. NPH insulin-loaded PF127 gel was prepared with varying concentrations of the polymer (15–25%) under mild conditions. The formulations were characterized for their gelling temperature, morphology, gel erosion, and in vitro insulin release, with trypsin concentrations up to 5 U/mL. Results: Scanning electron microscopy (SEM) showed that the integrity of NPH microcrystals was maintained after preparation. The burst release of insulin from NPH was significantly attenuated over the course of ~16h in the presence of PF127 with or without enzyme activity. Conclusion: NPH-PF127 successfully resisted the acceleration of NPH crystal dissolution and insulin release in vitro in the presence of protamine-degrading enzyme activity, warranting further testing.

Functional abnormalities of islets of Langerhans of obese hyperglycemic mouse.

1977 ◽  
Vol 233 (2) ◽  
pp. E86
Author(s):  
R L Lavine ◽  
N Voyles ◽  
P V Perrino ◽  
L Recant
Keyword(s):  
Insulin Release ◽  
Islets Of Langerhans ◽  
Food Restriction ◽  
Isolated Islets Of Langerhans ◽  
Lower Glucose ◽  
Islet Volume ◽  
Group 2 ◽  
In Vitro Insulin Release ◽  
Chronic Food Restriction

Glucose-induced insulin release was studied in vitro with isolated islets of Langerhans obtained from obese hyperglycemic C57Bl/6J-ob/ob (ob/ob) and lean C57Bl/6J-+/+ (control) mice. The threshold concentrations of glucose for insulin release were determined. In addition, the effect of total fast and of chronic food restriction on in vitro insulin release were studied. The following was observed: 1) with fasting, islet volume decreased. Islets obtained from ob/ob mice were larger than control islets, except for the chronic food restricted group. 2) Ob/ob islets were more sensitive to glucose than were controls in that the threshold for glucose-induced insulin release occured at lower glucose concentrations. 3) Fasting for 48 h completely abolished glucose-induced insulin release in control islets, whereas glucose-induced insulin release was maintained in 48-h and 7-day fasted ob/ob islets. 4) The increased glucose sensitivity of the ob/ob islets was maintained despite chronic food restriction.

In vitro insulin release from chicken pancreas

1977 ◽  
Vol 32 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Stephen P. Naber ◽  
Robert L. Hazelwood
Keyword(s):  
Insulin Release ◽  
In Vitro Insulin Release ◽  
Chicken Pancreas

Effects of gastric inhibitory polypeptide on leucine- and arginine-stimulated insulin release

1983 ◽  
Vol 245 (2) ◽  
pp. E114-E120
Author(s):  
E. L. Mazzaferri ◽  
L. Ciofalo ◽  
L. A. Waters ◽  
G. H. Starich ◽  
J. C. Groshong ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Insulin Release ◽  
Gastric Inhibitory Polypeptide ◽  
Serum Glucose ◽  
Isolated Islets ◽  
Perfusion Studies ◽  
In Vitro Insulin Release

Insulin release stimulated by single amino acids, with and without gastric inhibitory polypeptide (GIP), was studied in vivo in anesthetized rats and in vitro in collagenase-digested isolated rat pancreatic islets. Insulin release in vivo during a 15-min intravenous infusion of leucine (0.97 mM) or arginine (0.97 mM) with GIP (17 ng/min) was greater than with infusion of either amino acid or GIP alone. Serum immunoreactive GIP was in the physiological range, and serum glucose showed no significant change in these studies. In contrast, insulin release did not occur with valine infused alone or with GIP. Insulin release in vitro by isolated islets was greater during a 45-min incubation period with leucine (5-20 mM) or arginine (20 mM) plus GIP (10 ng to 10 micrograms/ml) than with either amino acid alone. This effect that occurred in the absence of glucose could not be demonstrated with low concentrations of leucine (1.5 mM) or with 20 mM valine. In vitro insulin release during paired perfusion studies of isolated islets was greater with leucine (20 mM) plus GIP (50 ng/min) than with leucine alone, and augmentation of insulin release by GIP was demonstrable in both the early and late phases of insulin release. From these results it is concluded that insulin release is greater, both in vivo and in vitro, after leucine or arginine plus GIP than with either amino acid or GIP alone. This effect appears to be specific for the insulinotropic amino acids tested, does not appear to be glucose dependent, and can be demonstrated in both the early and late phases of insulin release.

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