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Testis ecdysiotropin, an insect gonadotropin that induces synthesis of ecdysteroid
Author(s) -
Loeb Marcia J.,
De Loof Arnold,
Gelman Dale B.,
Hakim Raziel S.,
Jaffe Howard,
Kochansky Jan P.,
Meola Shirlee M.,
Schoofs Liliane,
Steel Colin,
Vafopoulou Xanthe,
Wagner Renee M.,
Woods Charles W.
Publication year - 2001
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.1050
Subject(s) - ecdysteroid , prothoracic gland , biology , medicine , endocrinology , rhodnius prolixus , hemolymph , juvenile hormone , insect , ecdysone , hormone , biochemistry , ecology
Testes of lepidoptera synthesized ecdysteroid in a somewhat different temporal pattern than the prothoracic glands that release ecdysteroid to the hemolymph. Brain extracts from Heliothis virescens and Lymantria dispar induced testes to synthesize ecdysteroid, but did not affect prothoracic glands. The testis ecdysiotropin (LTE) was isolated from L. dispar pupal brains by a series of high‐pressure chromatography steps. Its sequence was Ile‐Ser‐Asp‐Phe‐Asp‐Glu‐Tyr‐Glu‐Pro‐Leu‐Asn‐Asp‐Ala‐Asp‐Asn‐Asn‐Glu‐Val‐Leu‐Asp‐Phe‐OH, of molecular mass 2,473 Daltons. The predominant signaling pathway for LTE was via G i protein, IP 3 , diacylglycerol and PKC; a modulating pathway, apparently mediated by an angiotensin II‐like peptide, was controlled via G s protein, cAMP, and PKA. Testis ecdysteroid caused isolated testis sheaths to also synthesize a growth factor that induced development of the male genital tract. The growth factor appeared to be a glycoprotein similar to vertebrate α‐1‐glycoprotein. A polyclonal antibody to LTE indicated LTE‐like peptide in L. dispar brain medial neurosecretory cells, the suboesophageal, and other ganglia, and also in its target organ, the testis sheath. LTE immunoreactivity was also seen in testis sheaths of Rhodnius prolixus . LTE‐like immunoactivity was also detected in developing optic lobes, antennae, frontal ganglia, and elongating spermatids of developing L. dispar pupae. This may indicate that LTE has a role in development as well as stimulation of testis ecdysteroid synthesis. Arch. Insect Biochem. Physiol. 47:181–188, 2001. Published 2001 Wiley‐Liss, Inc.