title: Estradiol-17beta: tracing its metabolic significance in female fatbody of fifth instar larvae of silkworm, Bombyx mori L (race: Nistari).
abstract: In recent years, various vertebrate peptide and steroid hormones have been identified in invertebrates, estradiol-17beta (E2) being a major one. We have specifically shown NADP-malate dehydrogenase (NADP-MDH) activity in fifth instar larval fatbody of female silkworm, Bombyx mori, as an E2 responsive parameter. Interestingly enough, estradiol-induced increase in the enzyme activity could be counteracted by simultaneous application of specific E2-inhibitor, ICI-182780. Further, a nice correlation was obtained among the E2 titre, specific *E2 binding and expression of NADP-MDH activity in fatbody during different days of normal fifth instar larval development. Though the nature of the binding sites is quite similar to known steroid receptors of vertebrate, the reported absence of estrogen receptor gene in some insects poses a question. A recent finding regarding the presence of an estrogen-related receptor ortholog in fruit fly may provide some answers. The specific effects elicited by estradiol in the female fatbody of this insect support its possibility of having an important metabolic function. This role played by E2, whether hormonal or not, is yet to be identified.
authors.affiliation: Department of Animal Physiology, Bose Institute, P-1/12, C.I.T. Scheme VII M, Calcutta 700054, West Bengal, India.
authors.forename: Sumedha
authors.initials: S
authors.lastname: Roy
authors.forename: Jhuma
authors.initials: J
authors.lastname: De
authors.forename: Samita
authors.initials: S
authors.lastname: Kundu
authors.forename: Angshuman
authors.initials: A
authors.lastname: Biswas
authors.forename: Mitali
authors.initials: M
authors.lastname: Pramanik
authors.forename: Arun K
authors.initials: AK
authors.lastname: Ray
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D012831:Bombyx / Q000201:enzymology / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D004958:Estradiol / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D005260:Female; D000077267:Fulvestrant; D007814:Larva / Q000201:enzymology / Q000378:metabolism; D050538:Malate Dehydrogenase (NADP+) / Q000378:metabolism; D011485:Protein Binding
chemical_list: D004965:Estrogen Antagonists; D000077267:Fulvestrant; D004958:Estradiol; D050538:Malate Dehydrogenase (NADP+)