Je. Phillips et al., LOCUST ION-TRANSPORT PEPTIDE (ITP) - A PUTATIVE HORMONE CONTROLLING WATER AND IONIC BALANCE IN TERRESTRIAL INSECTS, American zoologist, 38(3), 1998, pp. 461-470
The anterior (ileum) and posterior (rectum) segments of the locust hin
dgut constitute the reabsorptive regions of the excretory system, whic
h conserves or eliminates body water and solutes as required for osmot
ic homeostasis. Hindgut transport mechanisms in the desert locust have
previously been well described but the neuropeptide hormones that may
naturally control these processes are only now being identified. Ion
Transport Peptide (ITP) has been isolated from locust corpus cardiacum
(CC) and its full sequence of 72 amino acids deduced from its cDNA, N
ative ITP has the same actions as crude CC extracts in stimulating Cl-
, Na+, K+, and fluid absorption and inhibiting H+ secretion (i,e., inf
luencing pH regulation), The deduced amino acid sequence of ITP was co
nfirmed by showing biological activity of expressed and synthetic form
s of this peptide. ITP has high sequence homology with a large family
of crustacean hormones that include hyperglycaemic (CHH) and moult-inh
ibiting hormones (MIH) and is the first member reported outside crusta
ceans.