Serum lipoprotein pattern in rats, dogs and monkeys, including method comparison and influence of menstrual cycle in monkeys.

The serum lipoprotein pattern (HDL-, LDL- and VLDL-cholesterol) was determined in normal untreated rats, dogs and monkeys using the density gradient centrifugation method, and compared with that in humans. The serum of rats (Wistar) and dogs (Beagle) was found to contain mainly HDL-cholesterol, whereas the serum of monkeys (Macaca fascicularis) consists of similar amounts of HDL-cholesterol and LDL-cholesterol, as in humans. In contrast to rats and dogs, monkeys showed a very low amount of serum VLDL-cholesterol. Comparison of four different methods (density gradient centrifugation, FPLC, agarose gel electrophoresis and precipitation methods) for determination of HDL- and LDL-cholesterol in monkey serum showed that density gradient centrifugation and FPLC-methods have the highest accuracy and recovery rate. The FPLC-method offers the extra advantages that it requires less sample volume and is less laborious. In a separate experiment, the influence of the menstrual cycle on the serum lipoprotein pattern was investigated in female monkeys. No changes in total cholesterol, HDL- or LDL-cholesterol were detected in serum samples obtained in the follicular and luteal phases of the cycle. In conclusion, monkeys (Macaca fascicularis) may be more suitable than rats or dogs for the comparison of the effect of different compounds on serum lipoproteins in pharmacological and toxicological studies, because the lipoprotein pattern in this species is similar to that of humans.