Delayed Effects of Juvenile Hormone on Insect Metamorphosis are mediated by the Corpus Allatum

Nature ◽  
1972 ◽  
Vol 237 (5356) ◽  
pp. 458-458 ◽  
Author(s):  
LYNN M. RIDDIFORD ◽  
JAMES W. TRUMAN
Keyword(s):  
Juvenile Hormone ◽  
Corpus Allatum ◽  
Delayed Effects ◽  
Insect Metamorphosis

scholarly journals Antagonistic actions of juvenile hormone and 20-hydroxyecdysone within the ring gland determine developmental transitions in Drosophila

2017 ◽  
Vol 115 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Suning Liu ◽  
Kang Li ◽  
Yue Gao ◽  
Xi Liu ◽  
Weiting Chen ◽  
...  
Keyword(s):  
Juvenile Hormone ◽  
Cross Talk ◽  
Steroid Hormone ◽  
Corpus Allatum ◽  
Prothoracic Gland ◽  
Transcription Factor Gene ◽  
Developmental Transitions ◽  
Larval Stages ◽  
Ring Gland ◽  
Insect Metamorphosis

In both vertebrates and insects, developmental transition from the juvenile stage to adulthood is regulated by steroid hormones. In insects, the steroid hormone, 20-hydroxyecdysone (20E), elicits metamorphosis, thus promoting this transition, while the sesquiterpenoid juvenile hormone (JH) antagonizes 20E signaling to prevent precocious metamorphosis during the larval stages. However, not much is known about the mechanisms involved in cross-talk between these two hormones. In this study, we discovered that in the ring gland (RG) of Drosophila larvae, JH and 20E control each other’s biosynthesis. JH induces expression of a Krüppel-like transcription factor gene Kr-h1 in the prothoracic gland (PG), a portion of the RG that produces the 20E precursor ecdysone. By reducing both steroidogenesis autoregulation and PG size, high levels of Kr-h1 in the PG inhibit ecdysteriod biosynthesis, thus maintaining juvenile status. JH biosynthesis is prevented by 20E in the corpus allatum, the other portion of the RG that produces JH, to ensure the occurrence of metamorphosis. Hence, antagonistic actions of JH and 20E within the RG determine developmental transitions in Drosophila. Our study proposes a mechanism of cross-talk between the two major hormones in the regulation of insect metamorphosis.

Hormone Balance and the Control of Metamorphosis in Rhodnius Prolixus (Hemiptera)

1952 ◽  
Vol 29 (4) ◽  
pp. 620-631
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Juvenile Hormone ◽  
Corpus Allatum ◽  
Corpora Allata ◽  
Stage Larva ◽  
Mature Adults ◽  
Hormone Balance ◽  
Low Concentrations ◽  
Moulting Cycle ◽  
Increased Activity ◽  
Reduced Activity

A technique is described by which the intact larva of Rhodnius can be transfused with blood from another larva without interfering with ecdysis. If the 4th-stage larva receives blood from a 3rd-stage larva it develops characters little different from those of the 4th instar. This is attributed to the 3rd-stage larva producing juvenile hormone at a higher concentration. If the 4th-stage larva at 24 hr. after feeding receives blood from another 4th-stage larva at 8 days after feeding it develops characters intermediate between those of the 4th and 5th instars. This is attributed to the juvenile hormone being introduced too early in the moulting cycle. The hormone balance is upset by abnormal temperatures. The 4th-stage larva will not moult at a temperature of 36° C. although the larvae can survive up to about 40° C. At temperatures a little below 36° C. moulting is somewhat delayed and the characters developed are slightly ‘adultoid’ (prothetely). This is attributed to slightly reduced activity of the corpus allatum. At temperatures below 20° C. moulting is greatly delayed and the characters developed are slightly ‘juvenile’ (metathetely). This is attributed to relatively increased activity of the corpus allatum. Low concentrations of oxygen (less than 5 %) have an effect similar to that of high temperature. If 5th-stage larvae of Rhodnius receive implants of corpora allata from mature adults of Periplaneta they develop into 6th-stage larvae and many of these subsequently into 7th-stage larvae. The ‘juvenile hormone’ appears to be the same in the two insects. No evidence could be obtained for the persistence of juvenile hormone in the blood from one instar of Rhodnius to the next. The hypothesis of an active elimination of juvenile hormone by the corpus allatum at the time of metamorphosis remains therefore unproven.

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