The effects of streptozotocin-induced hypoinsulinemia on serum lipid levels in spontaneously hyperlipidemic rats.
We compared the effects of streptozotocin (STZ) treatment on serum cholesterol and lipoprotein levels in spontaneously hyperlipidemic rats (HLR), a hereditary hyperlipidemic model animal, with those in Sprague-Dawley rats (SDR). The body weight of control SDR and HLR were increased continuously for 30 days. Both SDR and HLR lost their body weight after STZ administration. Glucose levels of SDR and HLR were significantly increased by STZ treatment. Insulin levels were markedly decreased in HLR compared with those in SDR. Serum cholesterol and triglyceride levels of HLR treated with STZ were significantly higher than those of untreated HLR. The increment of both levels in HLR was much larger than that in SDR. The high density lipoprotein (HDL) cholesterol level of the STZ-treated HLR was significantly lower than that of untreated HLR. In the STZ-treated HLR the intensities of both bands of the very low density lipoprotein (VLDL) and the low density lipoprotein (LDL) were higher than those in untreated HLR, while the intensity of any lipoprotein band remained unchanged between STZ-treated and control SDR. The atherogenic index (the ratio of total cholesterol level minus HDL cholesterol level of HDL cholesterol level) in the STZ-treated HLR was significantly high compared with that in other groups. The STZ-treated HLR showed the extremely hyperlipidemic state and this animal might be useful in experiments for the development of atherosclerosis or the drug evaluation for the agents used in hyperlipidemia.