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Abstract:
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About 80 years ago, the neurosecretory eyestalk structures and their role in
endocrine regulation was recognized in crustaceans. After the recognition it took half
a century to identify the first peptide hormone. Till date a large number of
homologous peptides of crustacean hyperglycaemic hormone and moult-inhibiting
hormone have been identified, consequently they are called the CHH family
hormones. This family comprises of highly multifunctional peptides which according
to sequences and precursor structures can be divided into two subfamilies, type-I
(CHH/ITP) and II (MIH, MOIH, VIH/GIH) (Webster et al., 2012). The XO-SG
complex has been the major site of the two subfamilies. The advent of molecular
techniques resulted in the characterization of different precursors of CHH, MIH and
GIH; these hormones consist of a signal peptide, but only the preprohormone of
CHHs contain a precursor- related peptide (CPRP) located between the signal and the
mature hormone (Weidemann et al., 1989; Klein et al., 1993b; De Kleijn and Van
Herp, 1995). The essentialities of the gene structure comply with the functions of the
CHH family hormones. The CHH family hormone functions are inhibitory as well as
stimulatory in the process of reproduction and maturation |