Abstract
In a previous paper 1 it was shown that an AP extract injected into New Zealand White female rabbits caused a significant depression of the plasma fat as determined by the Allen 2 method. Both the normal animals and the normal preinjection samples of blood from experimental animals showed rather large variations in plasma fat. Casual observations indicated that the lipid changes might be due to temperature changes accompanying the various seasons of the year. Further examination of our data indicated a rather definite drop in the plasma fat values during the increasingly cool weather in the fall, whereas the highest values appeared to be obtained during the hottest weather of the summer. On the other hand, previous studies on the seasonal variation in the blood lipids of the cow 2 and rabbit 3 did not indicate significant trends. The animals included in these studies were probably under fairly uniform temperature control in northern summer climate and housed during winter time. Recent study with the guinea pig 4 indicates an increased use of fat for maintenance under cold environment which condition might be expected to reduce the level of the blood lipids. Yet in the presence of an increased demand for fat, it would be possible for the blood lipids to remain high if the underlying mechanism regulating lipid metabolism was effective.
The object of this paper is to present a tabulation of our plasma lipid data according to season, in order to show the influence of temperature change with season upon blood lipids.
In this study as in the previous study, only mature New Zealand White female rabbits were used. Samples of ear blood were centrifuged and the plasma fat determined by Allen's method.
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