Ep. Widmaier et al., HIGH PLASMA-CHOLESTEROL, BUT LOW TRIGLYCERIDES AND PLAQUE-FREE ARTERIES, IN MEXICAN FREE-TAILED BATS, American journal of physiology. Regulatory, integrative and comparative physiology, 40(5), 1996, pp. 1101-1106
Female mammals typically become hyperphagic from mid- to late pregnanc
y and during lactation. Mexican free-tailed bats, Tadarida brasiliensi
s mexicana, double their nightly food intake from late pregnancy to pe
ak lactation and consume an insect diet that is exceptionally high in
fat. During late pregnancy and throughout lactation, fasting plasma le
vels of cholesterol in this insectivorous bat are high (215 +/- 8 mg/d
l) and are nearly 10-fold higher than in three species of Old World fr
ugivorous bats. Fasting triglycerides were unexpectedly low in T. bras
iliensis (25 +/- 2 mg/dl), despite evidence of high fat intake during
nightly feeding bouts (postprandial cholesterol and triglycerides, 268
+/- 18 and 122 +/- 20 mg/dl, respectively). High-density lipoprotein
(HDL) cholesterol levels were extraordinarily high (124 +/- 5 mg/dl) a
nd unaffected by feeding. Low-density lipoprotein cholesterol levels w
ere correspondingly low (86 +/- 7 mg/dl). This unusual plasma lipid pr
ofile was not associated with coronary or aortic atherosclerosis, nor
was there evidence of hyperglycemia or hyperinsulinemia. A high-fat di
et and high levels of cholesterol in T. brasiliensis are not correlate
d with cardiovascular disease or (possibly) insulin resistance. Among
several possible factors that might account for these observations, ni
ghtly bouts of powered flight (commuting and foraging for food) may co
ntribute to elevated HDL cholesterol, which may protect this species f
rom developing atherosclerosis.