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J.-COMP.-PHYSIOL., B 160 (1): 51-59 (1990)

Hormonal control of hemolymph lipoprotein ice nucleators in overwintering freeze-susceptible larvae of the stag beetle Ceruchus piceus : Adipokinetic hormone and juvenile hormone.

Lei; Neven Xu , JG Duman
ABSTRACT
Freeze-resistant overwintering larvae of the stag beetle Ceruchus piceus do not produce antifreezes in winter, but instead lower their supercooling points by seasonal removal of lipoprotein ice nucleators (LPINs) from the hemolymph. The normal lipid transport function of these lipoproteins becomes less essential during winter because of the low temperatures and the diapause state of the larvae. Adipokinetic hormone (AKH) and juvenile hormone (JH) were shown to be involved in the control of supercooling abilities and LPIN levels. Treatment of midwinter larvae with AKH resulted in an increase in ice nucleator activity within 2 h, associated with elevated levels of LPINs. In contrast, JH treatments of larvae with high hemolymph ice nucleator contents (either autumn or spring larvae) caused a decrease in ice nucleator activity and supercooling points. AN: 2265165
Notes
Hormonal control of hemolymph lipoprotein ice nucleators in overwintering freeze-susceptible larvae of the stag beetle Ceruchus piceus : Adipokinetic hormone and juvenile hormone.English