Oscillations of circulating plasma insulin concentrations in the rat
| Autor: | Robert F. McGivern, Eli Ipp, Hsu-Fang Chou, Nancy Berman |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Periodicity
medicine.medical_specialty Light Red Cell Pancreatic islets Insulin medicine.medical_treatment Pulsatile flow Rats Inbred Strains General Medicine Biology General Biochemistry Genetics and Molecular Biology Rats Insulin oscillation Endocrinology medicine.anatomical_structure In vivo Internal medicine Blood plasma medicine Animals General Pharmacology Toxicology and Pharmaceutics Pancreatic hormone |
| Zdroj: | Life Sciences. 48:1463-1469 |
| ISSN: | 0024-3205 |
| DOI: | 10.1016/0024-3205(91)90183-c |
| Popis: | In previous studies, we found that insulin is secreted in a pulsatile fashion in vitro in isolated rat pancreatic islets. This study evaluated whether similar plasma insulin fluctuations occur in the rat in vivo. Freely moving rats were implanted with a chronic jugular catheter and serial blood samples were obtained 48-72 hrs post surgery. Blood was sampled at 3 min intervals for 60 mins with volume replacement using a red cell preparation. Plasma insulin concentrations were observed to fluctuate around a mean of 10.6 +/- 1.1 uU/ml, with an amplitude of 4.7 +/- 0.5 uU/ml and a period of 13.3 +/- 1 mins (n = 6). This was similar to the cycling observed in isolated islets at similar glucose concentrations. Sampling during the dark phase of the light-dark cycle in the rat was associated with an increase in the mean plasma level, amplitude and period of insulin oscillations compared with values obtained during the light phase (n = 3). These data are the first in vivo demonstration of oscillatory circulating insulin concentrations in the rat and show that the pulsatility in this species is similar to that observed in other mammals including man. We conclude that the chronically catheterised rat is a useful model for the evaluation of oscillating insulin concentrations in vivo, and may provide interesting insights by comparison with in vitro data in the same species. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|