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Circulating forms of somatostatinlike immunoreactivity in human plasma
The American Journal of Physiology
|April 1, 1986
Summary
Human plasma contains four forms of somatostatinlike immunoreactivity (SLI), including immunoglobulins, somatostatin-28 (S-28), somatostatin-14 (S-14), and S-13. S-14 is partly converted to S-13 in circulation, and these forms are elevated in cirrhosis and renal failure.
Area of Science:
- Endocrinology
- Biochemistry
- Immunology
Background:
- Circulating somatostatinlike immunoreactivity (SLI) exists in various molecular forms.
- Understanding these forms is crucial for interpreting SLI measurements in physiological and pathological states.
Purpose of the Study:
- To characterize the different molecular forms of circulating SLI in humans.
- To investigate the presence and levels of SLI forms in patients with renal failure and cirrhosis.
Main Methods:
- Gel filtration chromatography and protein A-Sepharose chromatography were used to separate SLI forms.
- Octadecyl silyl silica cartridge extraction and high-pressure liquid chromatography (HPLC) were employed for further analysis.
- SLI concentrations were measured in normal subjects and patients with renal failure or cirrhosis.
Main Results:
- Over 90% of circulating SLI is high molecular weight (MW), primarily cross-reacting immunoglobulins.
- Two lower MW forms coelute with somatostatin-28 (S-28) and somatostatin-14 (S-14).
- S-14 is partially converted to Des-Alasomatostatin (S-13) in circulation.
- High MW SLI is elevated in cirrhosis; S-28 and S-13/14 are elevated in both renal failure and cirrhosis.
Conclusions:
- Human plasma contains at least four SLI forms: immunoglobulins, S-28, S-14, and S-13.
- Circulating S-14 undergoes conversion to S-13.
- Altered levels of specific SLI forms are associated with cirrhosis and chronic renal failure.