Ea. Santos et R. Keller, CRUSTACEAN HYPERGLYCEMIC HORMONE (CHH) AND THE REGULATION OF CARBOHYDRATE-METABOLISM - CURRENT PERSPECTIVES, Comparative biochemistry and physiology. Part A, Physiology, 106(3), 1993, pp. 405-411
1. Even though the crustacean hyperglycemic hormones (CHHs), produced
by perikarya in the ''medulla terminalis X-organ'' and released from t
he sinus glands, are among the best known crustacean neuropeptides, th
eir physiological role in metabolic regulation is far from clear. 2. P
revious experiments with eyestalk extract or partially purified prepar
ations have provided evidence of an activating effect on phosphorylase
and an inhibitory one on glycogen synthase. It is likely that CHH has
this dual role, but the details remain to be confirmed by experiments
with pure hormone, particularly with regard to the effects on the pho
sphorylase system. 3. There is evidence in the literature that glycoly
sis in crustacean tissues may be controlled by an eyestalk factor, and
recent results suggest that this factor may be CHH. 4. The pentose ph
osphate pathway has been suggested, about 30 years ago, to be under th
e control of two eyestalk factors. Until now no significant efforts ha
ve been made to identify any of them, one of which may be CHH. 5. Alth
ough the main metabolic pathways of carbohydrate metabolism have been
demonstrated in crustaceans, very little is known about their operatio
n under altered environmental and/or physiological conditions, and eve
n less about their endocrine control. There is evidence that CHH may h
ave a more prominent, central role in such control than has been assum
ed thus far.