Fibronectin in diabetic and starved rats: An immunochemical study

We assessed the plasma fibronectin concentrations and the immunolocalization of fibronectin in the kidney and liver of semistarved rats and in rats with streptozotocin-induced diabetes. When rats were semistarved for 9 days, the plasma fibronectin levels, measured by a specific immunoturbidimetric method, were significantly reduced in the semistarved animals (mean: 50 ± 10 mg/l) when compared with controls (mean: 97 ± 21 mg/l). Plasma fibronectin levels in diabetic rats were no different from controls. Immunohistochemical studies using antifibronectin antibodies showed that immunoreactive fibronectin localizes mainly in relation to blood vessels in the tissues studied. While there was no major difference in either the degree or the location of the immunostaining between the control and diabetic rats, tissue fibronectin in the kidney and liver was markedly reduced in semistarved animals. We conclude that semistarvation and the associated catabolic state result in a marked loss of plasma and tissue fibronectin while non-ketonuric diabetes in the rat does not induce significant changes in either the plasma concentration or tissue fibronectin.