Kj. Siegert, HYPOLIPEMIA, HYPOGLYCEMIA, AND INACTIVATION OF GLYCOGEN-PHOSPHORYLASEIN LOCUSTA-MIGRATORIA, Archives of insect biochemistry and physiology, 29(4), 1995, pp. 343-355
Feeding starved adult migratory locusts, Locusta migratoria, caused de
creases of hemolymph lipid concentrations and of the percentage of act
ive fat body glycogen phosphorylase which suggested that a molecule(s)
from the neurosecretory system or the midgut may have been released t
o regulate metabolism. Fat body phosphorylase was also inactivated aft
er insects were transferred from 0 to 25 degrees C. In adults with ele
vated hemolymph lipid levels after the injection of small doses of cor
pus cardiacum extract (CC), feeding did not induce a decrease in hemol
ymph lipid concentrations. It appears that the processes initiated by
feeding could not override the effects of the continued presence of ad
ipokinetic hormone(s) (AKHs) in the hemolymph or their long-term effec
ts. Aqueous, methanolic, or ethanolic extracts of brains or storage lo
bes (SL) of fed locust CC did not lead to decreases of hemolymph lipid
concentrations. Bovine insulin was equally inactive when tested at do
ses which were previously reported to reduce lipid levels. Fractions o
f ethanolic brain extracts from 3-day-starved males collected after hi
gh-performance size-exclusion chromatography, however, produced hypogl
ycemic effects in fed males. Two biologically active fractions were fo
und, one with high (greater than or equal to 10 kDa) and one with low
molecular weight (approximately 1 kDa). (C) 1995 Wiley-Liss, Inc.