Prothoracic glands

The secretion from the prothoracic glands of the lacewing Chrysopa oculata (Chrysopidae) contains skatole (140) and tridecene (Table VIII) and offers some protection against invertebrate predators, such as ants. Uric acid (95) is stored as one of the excretory products of nitrogenous metabolism in fat bodies of the larvae of C. carnea (Table VI). 

E, Eye H, hemolymph P, pupae I, larval integument B, whole body F, feces Pr, prothoracic gland S, secretion L, larvae W, wings. 

Sehgal I disagree. We found that there is a clock in the prothoracic gland that controls eclosion and the lateral neurons are required for the cycling of the prothoracic gland. There are some clocks in Drosophila that are not autonomous. 

Dethier, V. G. (1939). Prothoracic glands of adult lepidoptera. Journal of the New York Entomological Society 47 131-144. 

Noldt U., Fettkother R. and Dettner K. (1995) Structure of the sex pheromone-producing prothoracic glands of the male old house borer, Hylotrupes bajulus (L.) (Coleoptera Cerambycidae). Int. J. Insect Morphol. Embrol. 24, 223-234. 

In adult insects the prothoracic gland ceases to function, and the gonads take over ecdysteroid production. In adult Crustacea moulting continues and the Y-organs continue to function, so that there is limited evidence about alternative sites of production. Lafont and Mathieu39 point out that there is no clear evidence that crustacean ovaries produce ecdysteroids, and there is still less evidence that males produce them. 

The synthesis of ecdysone, the only ecdysteroid formed by the prothoracic glands, is under the control of the prothoracicotropic... 

The similarities between ecdysone synthesis in the insect prothoracic gland and the ovary are obvious and in each case synthesis is initiated in response to a hormone originating in the brain. Both bear a striking resemblance to the mammalian system where steroid hormone synthesis in the various endocrine tissues is initiated in response to the release of appropriate hormones from the anterior pituitary. 

The Bombyx PTTH was active at a dose of ca. 0.1 ng, when injected into brainless Bombyx pupae, but was completely inactive in debrained Sarnia pupae even at a dose of 10 ng (11). The Bombyx PTTH also enhanced the release of ecdysone by the prothoracic gland of Bombyx in vitro at a concentration of... 

Ecdysone is a steroid that is formed and secreted by the prothoracic glands of immature insects but also by the ovaries of adult female insects. It was first isolated from the silk worm, Bombix mori. Bedstone is the prohormone of the moulting hormone eedysterone, but the prohormone has also effects on its own at other stages of insect development. 

Hormones have an important role in insect metamorphosis. In many species, two classes of hormones, moltirp hormones (made by the prothoracic glands) and juvenile hormones (made by the corpora allata) act together to control metamorphosis. Each regulates the expression of different genes, so that a charpe in their relative concentrations causes metamorphosis, the development of different body patterns. 

Molting, which is defined as the shedding of an outer covering as part of a periodic process of growth, is central to the development of insects. Release of ecdysteroids, or molting hormones, from the prothoracic glands is controlled by a neuropeptide called the prothoracicotropic hormone (PTTH) produced by neurosecretory cells and released by corpora cardiaca. 

In insects, ecdysone is secreted from the prothoracic glands (PG) at every moulting and pupal stage. Conversion of ecdysone to 20-hydroxyecdysone occurred in fat body, Malpighian tubules, gut and body wall tissues [189]. Although ecdysone may have direct hormonal effects, it is generally held that ecdysone serves as a prehormone that is converted to 20-hydroxyecdysone which functions as the active hormone. This is because in many bioassay systems, 20-hydroxyecdysone appears to be much more active than ecdysone. 

Karlson and Hoffmeister first demonstrated the conversion of [ H]cholesterol to ecdysone in Calliphora erythrocephala. Subsequently, the conversion was reported in other species. Direct evidence for the secretion of ecdysone from prothoracic glands has been provided by in vitro culture of such organs in appropriate media. The incorporation of radioactive cholesterol into ecdysone by such glands has been reported for B. mori [190], Manduca sexta [191], and Leucophaea manderae [192]. 

In insects and in crustaceans, the synthesis of both ecdysteroids and JH/MF are subject to control by neuropeptides. Although ecdysteroids are considered to be growth promoting hormones in both insects and crustaceans, these steroid hormones are differently regulated in the two taxa. In insects, the synthesis and release of ecdysteroids from the prothoracic gland is positively regulated by the prothoracicotropic hormone (PTTH) which is synthesized in neurosecretory cells of the brain and released from the CA [37]. PTTH was first completely identified in B. 

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