• Korean journal of applied entomology
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• v.40 no.2
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• pp.155-196
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• 2001

Basically insect hormones include ecdysteroids (molting hormone), juvenile hormones, and neurohormones comprising neuropeptides and biogenic amines. This article reviewed their chemical structures and biological functions. The active molting hormone is 20-hydroxyecdysone in most insects but makisterone A in some other insects including the honey bee and several phytophagous hemipterans. Most insects use JH III, but lepidopterans JH I and II. Dipterans also use a different JH, so-called JH $B_3$(JH III bisepoxide) and we still do not know the exact chemical structure of JH utilized in hemipterans. Some other insects use methyl farnesoate or hydroxylated JH III analogues as their juvenile hormone. Most diverse pictures can be found in neurohormones (NH), especially in neuropeptides, in terms of their number and structure. There are more than 200 neuropeptides (NP), classified into more than 30 families, which structures have been identified, and more of them are expected to be reported in the near future, partly due to rapid development in molecular biological techniques and in analytical techniques. More than half of them are involved in controlling activity of visceral muscles. But function (s) of many NPs are not clarified yet, even though their amino acid sequences have been identified. It is partly due to the fact that a single NP may have multiple functions. Another interesting point is their gene structure, having many number of independent, active peptides in one gene, apparently working for similar or totally different functions. NH also includes amines, such as octopamine, dopamine, serotonin, etc. From now on, investigation will be concentrated on identifying their function (s) and receptors, and on possibilities of their utilization as control agents against pest insects.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.205-207
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• 1999

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.05a
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• pp.40-40
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• 2000

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.11-19
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• 2001

This review discusses the effects and roles of insect hormones and insect growth regulators (IGRs) on vitellogenesis in adult insects. Insect vitellogenesis is regulated by hormones such as juvenile hormone (JH), ecdysteroids, and neurosecretory hormones (ovaryecdysteroidogenic hormone : OEH) released by neurosecretory cells, diet, and other elements(male specific protein of sperm fluid). In the fat bodies, the vitellogenins are synthesized by the stimulation of JH released by corpus allatum (CA) and ecdysteroids produced by follicle cells with the ovary in most insects. Furthermore, vitellogenins are released into the hemolymph, transported to the ovarioles by carrier protein, and incorporated into oocytes for the developing ovary. Of IGRs, juvenile hormone and its mimics such as methoprene and pyriproxifen appear to have pharmacological effects such as membrane lysis, destruction of salivary grand and midgut epithlial cells, fat body cells, and ovarian tissue, and also anti-juvenile hormone such as precocenes I and II appear to have specific cytotoxicity such as inhibition of corpus allatum and oocytes development. These results suggest that IGRs may be useful as agents for integrated pest management.

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.2
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• pp.79-83
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• 2006

We successfully extirpated all four hemopoietic organ-wing disc complexes of the fifth instar larvae of Bombyx mori, and found that most of the treated silkworms could still develop into the moths. We investigated the changes of the circulating hemocytes and evaluated the effects of extirpation on the hemopoiesis. The results showed that proliferation of circulating hemocytes was sufficient to allow development of the silkworms which complexes were totally extirpated. We also found that hemopoietic organ-wing disc complexes extirpation might cause a certain hemopoietic compensation of the remainder complexes during early spinning. Exogenous hormones such as $20-{\beta}-hydroxyecdysone$ and juvenile hormone analog had a positive effect on hemocytes proliferation.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.13-18
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• 2003

Allatotropin is a 13-residue amidated neuropeptide isolated from pharate adult heads of the tobacco hornworm, Manduca serta and strongly stimulates biosynthesis of juvenile hormones in adults, but not larval, lepidopteran corpora allata. From a Bombyx mori midgut cDNA library, a cDNA that encodes a 130-amino-acid polypeptide containing M. sexta allatotropin sequence was isolated. The B. mori allatotropin cDNA consists of 1196 nucleotides. (omitted)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.293-294
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• 2001

In nutrition studies of fish, determining the optimum dietary protein level for growth of fish is generally a primary consideration because protein is not only the major constituent of fish body, but also it has critical functions as enzymes and hormones. Many studies have been carried out to determine the protein requirements of fish, and the estimated protein requirements range from 30％ to 55％ of diet. (omitted)

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.137-141
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• 2002

An experimental study was undertaken to quantify the effects of insect hormones on the replication of nucleopolyhedrovirus (NPV). The results demonstrated that TCID/ sub 50/ at 72 h post-infection (hpi) rose systematically from 0.55$\times$10$^{8}$ /m1, for untreated cells, up to 1.67$\times$10$^{8}$ / ml at 3$\mu$g/ml, then dropped down to 1.45$\times$10$^{8}$ /m1 at 4 $\mu$g/ml, by adding ecdysone to the culture medium for Bm-N cells infected with a wild-type Bambyx mori. nucleopolyhedrovirus (BmNPV). The optimum enhancement of about 3 times on budded virus (BV) titer at 72 hpi was given at 3 $\mu$g/ml of ecdysone. While the polyhedra number had no obvious variation within the range of concentrations from 0 to 4 $\mu$g/ml. By addition of juvenile hormone analogue (JHA) into the media with this concentration range, the BmNPV TCID/ sub 50/ and polyhedra number at 72 hpi did not show significant changes. Also, the addition of either 3 $\mu$g/ml of ecdysone or 3 $\mu$g/ml of JHA to the culture media did not appear to affect the TCID/ sub 50/ and polyhedra number significantly in infected Sf-21 cells with the autographa californica nucleopolyhedrovirus (AcMNPV).

• Fisheries and Aquatic Sciences
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• v.11 no.4
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• pp.183-189
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• 2008

In this study, tests were conducted to investigate the effects of three dietary growth hormones, administered in various amounts, on the growth performance and lysozyme activity in juvenile olive flounder, Paralichthys olivaceus. Three dietary growth hormones, recombinant human growth hormone (rHGH), recombinant bovine somatotropin A (rBST A) and recombinant bovine somatotropin B (rBST B) were tested at three different supplemental levels (10, 20 or 40 mg/kg body weight per week) by a $3{\times}3$ factorial design and a complete randomized design in comparison to a control group. Fish were fed one of the ten experimental diets (control, $rHGH_{10}$, $rHGH_{20}$, $rHGH_{40}$, rBST $A_{10}$, rBST $A_{20}$, rBST $A_{40}$, rBST $B_{10}$, rBST $B_{20}$ and rBST $B_{40}$) for 6 weeks and afterward were analyzed for growth performance by measuring weight gain (WG), feed efficiency (FE), specific growth rate (SGR) and protein efficiency ratio (PER). Based on the factorial design analysis, fish fed rHGH diets demonstrated significantly higher growth performance than fish fed rBST A or rBST B diets. However there were no significant differences in WG, FE, SGR and PER between fish fed rBST A and rBST B diets. Neither hormone level nor the interaction between the different hormones and their various levels had a significant effect on WG, FE, SGR, PER, lysozyme activity or whole-body proximate composition. A complete randomized design analysis confirmed fish fed $rHGH_{10}$, $rHGH_{20}$, $rHGH_{40}$, rBST $A_{10}$, rBST $A_{20}$, rBST $A_{40}$, rBST $B_{20}$ and rBST $B_{40}$ diets for 6 weeks showed higher WG than fish fed the control diet (P<0.05). A higher FE was observed in fish fed $rHGH_{10}$, $rHGH_{20}$, $rHGH_{40}$, rBST $A_{20}$ and rBST $A_{40}$ diets in comparison to fish fed the control diet. Fish fed all graded rHGH, rBST A and rBST B supplemented diets showed a higher SGR than fish fed the control diet. Regarding PER, fish fed $rHGH_{10}$, $rHGH_{20}$, $rHGH_{40}$, rBST $A_{10}$, rBST $A_{20}$, rBST $A_{40}$ and rBST $B_{20}$ diets were higher than fish fed the control diet. Furthermore, the lysozyme activity of fish fed a diet of $rHGH_{20}$ was significantly higher than that of fish fed any other diet. The results measuring the growth and development of the fish clearly suggest the biopotency of dietary rHGH could be higher than those of both dietary rBST A and rBST B. Further implied is the probability that within the range of 10 to 40 mg/kg BW/week the dietary growth hormones could accelerate growth performance, and that 20 mg rHGH/kg BW/week could possibly enhance lysozyme activity in juvenile olive flounder, Paralichthys olivaceus.

• Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.48-57
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• 2023

One of the ways to increase the production for aquaculture is through the cultivation of monosexuals by ensuring genital reversal from which energy for reproduction is diverted towards growth. Masculinization has been identified as one of the most prominent techniques, where sex development was directed from female to male. This approach only altered the phenotype and not the genotype. The red claw crayfish (Cherax quadricarinatus) was a relatively new commercial commodity, and the males were known to grow faster than females. Hence, it was proposed to use monocultures comprising an all-male population to increase yield using steroid hormone, synthetic 17α-methyltestosterone. However, this technique generated residues that detrimentally affect human health, the environment, and cultivated organisms. Therefore, finding new safe natural steroid sources was essential, and one of which is exploring of natural hormones extracted from the viscera of sea cucumbers (Holothuria scabra Jaeger). This study focused on the determination of male formation and testosterone levels among juvenile crayfish, after immersing in sea cucumber steroid extract (SCSE). A completely random design with factorial was used with two variables, encompassing the varied doses (0, 2, 4 mg/L, 2 mg/L 17α-methyl testosterone as control group) and immersion times of 18 and 30 h. The result showed the dose-dependent ability of SCSE increase the male genital formation and promote the testosterone level of juvenile crayfish. In addition, the testosterone was influenced by dose and immersion duration time, with the highest level of testosterone observed in treatments of 4 mg/L SCSE with 30 h immersion was 0.248 ng/mL, while the male percentage was 77%. In conclusion, the combination of dose and immersion time significantly affected growth and testosterone levels.