Cyclosporine A enhances gluconeogenesis while sirolimus impairs insulin signaling in peripheral tissues after 3 weeks of treatment

• Cyclosporine A (CsA) and sirolimus (SRL) are immunosuppressive agents (IA) associated with new-onset diabetes after transplantation (NODAT). This study aims to evaluate the effects of 3-weeks of treatment with either CsA (5 mg/kg BW/day) or SRL (1 mg/kg BW/day) on insulin signaling and expression of markers involved in glucose metabolism in insulin-sensitive tissues, in Wistar rats. Although no differences were observed in fasting glucose, insulin or C-peptide levels, both treated groups displayed an impaired glucose excursion during both glucose and insulin tolerance tests. These results suggest glucose intolerance and insulin resistance. An increase in glucose-6-phosphatase protein levels (68%, p<0.05) and in protein-tyrosine phosphatase 1B (163%,p<0.05), a negative regulator of insulin was observed in the CsA-treated group in the liver, indicating enhanced gluconeogenesis and increased insulin resistance. On the other hand, glucokinase protein levels were decreased in the SRL group (35%, p < 0.05) compared to vehicle, suggesting a decrease in glucose disposal. SRI treatment also reduced peroxisome proliferator-activated receptor gamma coactivator 1 alpha protein expression in muscle (similar to 50%, p<0.05), while no further protein alterations were observed in muscle and perirenal adipose tissue nor with the CsA treatment. Moreover, the phosphorylation of key proteins of the insulin signaling cascade was suppressed in the SRL group, but was unchanged by the CsA treatment. Taken together, these data suggest that CsA treatment enhances gluconeogenic factors in liver, while SRL treatment impairs insulin signaling in peripheral tissues, which can contribute to the development of insulin resistance and NODAT associated with immunosuppressive therapy.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmakologi och toxikologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmacology and Toxicology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)

Nyckelord

Immunosuppressive agents

Insulin signaling

Gluconeogenesis

Adipocyte

Muscle

Liver

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