Tebufenozide disrupts ovarian development and function in silkmoths

• Published in: Insect biochemistry and molecular biology Vol. 43; no. 12; pp. 1087 - 1099
• Main Authors: Sridhara, S., Lee, Vaughan H.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2013
• Subjects: 20-Hydroxyecdysone; adult development; adults; agonists; Animals; antagonists; Bombyx - drug effects; Bombyx - growth & development; ecdysterone; Ecdysterone - genetics; Ecdysterone - metabolism; eggs; epithelium; Female; hemolymph; Hemolymph - metabolism; Hydrazines - administration & dosage; insects; laboratory animals; oogenesis; Oogenesis - drug effects; ovarian development; Ovary; Ovary - drug effects; Ovary - growth & development; RNA; Silkmoths; steroid hormones; Tebufenozide; Vitellogenesis - drug effects; Vitellogenesis - genetics; Vitellogenin; Vitellogenins - genetics; Vitellogenins - metabolism; Lp; Hl; DMSO; 20E; 20-Hydroxyecdysone; Vitellogenin; PTU; Ovary; Vg; USP; Tebufenozide; EcR; PTTH; Silkmoths; lipophorin or arylphorin; ecdysone receptor; phenylthiourea; 20.hydroxyecdysone; hemolymph; prothoracicotrophic hormone; dimethyl sulfoxide; ultraspiracle; vitellogenin or vitellin
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2013.09.002

Adult development and production of up to 400 eggs within the pupal case of female silkmoths are both dependent on 20-hydroxyecdysone (20E), the steroid hormone of insects. When adult development was initiated with tebufenozide, the non-steroidal ecdysteroid agonist, instead of 20E, full development of all epidermal tissues like the wing was witnessed, but ovarian growth and egg formation was minimal. Administration of tebufenozide to female pharate adults caused disruption of the follicular epithelium, produced nurse cell damage, and inhibited oogenesis. Reduced ability to synthesize RNA and protein accompanied these tebufenozide induced morphological disturbances of the follicles. In vivo accumulation of vitellogenin (Vg) from the hemolymph was reduced in tebufenozide treated female ovaries as well as their ability to accumulate Vg in vitro. Determination of protein staining intensity and antibody reactivity of Vg pointed out that hemolymph Vg level remained fairly constant all through adult development whether induced by 20E or tebufenozide. Measurement of hemolymph volumes and hemolymph Vg levels of control and experimental animals allowed us to conclude that egg development involves the uptake of all the hemolymph proteins and not Vg alone. The loss of hemolymph that accompanies egg maturation was considerably reduced in tebufenozide initiated female pharate adults. 20E could not overcome ovarian growth inhibitory effects of tebufenozide. Dual mechanisms, one involving ecdysteroid antagonist action at the beginning of development, and the other unrelated to that function during heightened egg formation, are needed explain the biphasic inhibitory actions of tebufenozide on silkmoth ovaries. [Display omitted] •Tebufenozide acts as an ecdysteroid on epidermal tissues, but inhibits ovarian growth in silkmoths during adult development.•Tebufenozide disrupts ovarian development and function in pharate adults.•Tebufenozide blocks vitellogenin uptake and retention.•20-hydroxyecdysone cannot overcome inhibitory effects of tebufenozide on the ovary.•Egg formation involves the uptake of the entire protein complement of the hemolymph.