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Somatostatin modulates the function of Kupffer cells
1Department of Surgery, Chang Gung Medical College and Chang Gung Memorial Hospital, Taipei, Taiwan.
Abstract:
Recent studies have shown that somatostatin modulates lymphocyte and peritoneal macrophage function, but the effects of somatostatin on hepatic macrophages (Kupffer cells) are not clearly defined. In the present study, hepatic macrophages obtained from male rats were treated in vitro with somatostatin or octreotide and their effects on the release of nitrite, tumor necrosis factor (TNF), and hydrogen peroxide (H2O2) determined. At concentrations of 10(-14) M to 10(-12) M, or greater than 10(-10) M, somatostatin suppressed nitrite release by Kupffer cells. At concentrations of less than 10(-9) M or greater than 10(-9) M, octreotide inhibited nitrite release by Kupffer cells. Kupffer cells treated with 10(-10) M to 10(-14) M or greater than 10(-8) M of somatostatin released significantly less amounts of TNF than did the untreated controls. TNF release by Kupffer cells treated with 10(-15) M to 10(-5) M of octreotide was significantly inhibited as compared to that of untreated controls. Kupffer cells treated with 10(-14) M to 10(-11) M and 10(-9) M to 10(-8) M of somatostatin released more H2O2 than did the untreated controls. The amount of H2O2 released by noncirrhotic Kupffer cells treated with 10(-6) M or 10(-5) M of somatostatin was less than that of controls. These findings demonstrate that somatostatin and octreotide modulate the release of nitric oxide, TNF, H2O be Kupffer cells depending on the concentration of hormones used.
Insights
Somatostatin and octreotide impact Kupffer cell function by altering the release of nitric oxide, tumor necrosis factor (TNF), and hydrogen peroxide (H2O2). These effects are concentration-dependent, influencing immune responses in the liver.
Area of Science:
- Immunology
- Endocrinology
- Hepatology
Background:
- Somatostatin's role in modulating immune cells like lymphocytes and peritoneal macrophages is known.
- The specific effects of somatostatin on hepatic macrophages, known as Kupffer cells, remain unclear.
- Understanding Kupffer cell responses is crucial for liver health and immune regulation.
Purpose of the Study:
- To investigate the in vitro effects of somatostatin and octreotide on Kupffer cell function.
- To determine how these hormones influence the release of key mediators: nitrite, tumor necrosis factor (TNF), and hydrogen peroxide (H2O2).
- To elucidate the concentration-dependent actions of somatostatin and octreotide on Kupffer cells.
Main Methods:
- Hepatic macrophages (Kupffer cells) were isolated from male rats.
- Cells were treated in vitro with varying concentrations of somatostatin or octreotide.
- The release of nitrite, TNF, and H2O2 from treated Kupffer cells was measured and compared to controls.
Main Results:
- Somatostatin and octreotide differentially modulated nitrite release by Kupffer cells based on hormone concentration.
- Both somatostatin and octreotide significantly inhibited TNF release from Kupffer cells across specific concentration ranges.
- Kupffer cells exhibited altered H2O2 release in response to somatostatin, with both increases and decreases observed depending on concentration.
Conclusions:
- Somatostatin and octreotide act as modulators of Kupffer cell activity.
- The observed effects on nitric oxide, TNF, and H2O2 release are critically dependent on the concentration of the hormones used.
- These findings highlight the complex regulatory role of somatostatin and its analog in hepatic macrophage function.