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Glucagon and VIP in the retina
Investigative Ophthalmology & Visual Science
|October 1, 1985
Summary
This study quantifies glucagon-like and vasoactive intestinal polypeptide (VIP) in various animal retinas. Findings reveal species-specific distribution patterns for these important retinal neuropeptides.
Area of Science:
- Neuroscience
- Comparative Biology
- Biochemistry
Background:
- Immunohistochemistry has identified glucagon and vasoactive intestinal polypeptide (VIP) in retinal neurons across species.
- Quantifying these neuropeptides in retinal tissue requires sensitive biochemical assays.
Purpose of the Study:
- To determine and compare the concentrations of glucagon-like and VIP-like materials in the retinae of diverse animal species.
- To characterize the molecular properties of retinal glucagon-like and VIP-like immunoreactive materials.
Main Methods:
- Radioimmunoassay (RIA) was employed to quantify glucagon-like and VIP-like material concentrations in retinal extracts.
- Gel chromatography and high-performance liquid chromatography (HPLC) were used for molecular size characterization.
Main Results:
- Retinae from goldfish, chicken, pigeon, and frog showed significant glucagon-like immunoreactivity (10-35 pg/mg).
- Retinae from cow, pig, rabbit, and rat were rich in VIP-like material, while cat, guinea pig, and goldfish had very little.
- Molecular analysis indicated retinal glucagon-like material in chickens and frogs is similar in size to porcine pancreatic glucagon.
- Bovine retinal VIP-like material exhibited a molecular size comparable to authentic porcine VIP.
Conclusions:
- Retinal neuropeptide distribution, specifically glucagon-like and VIP-like immunoreactivity, varies significantly across species.
- The molecular characteristics of these retinal neuropeptides align with known pancreatic counterparts, suggesting conserved biochemical properties.