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Shalom W. Applebaum - One of the best experts on this subject based on the ideXlab platform.
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Methyl palmitate: a novel product of the Medfly (Ceratitis capitata) Corpus Allatum.
Insect biochemistry and molecular biology, 2003Co-Authors: Pnina Moshitzky, Irena Miloslavski, Zeev Aizenshtat, Shalom W. ApplebaumAbstract:The Corpus Allatum (CA) of adult female Ceratitis capitata produces methyl palmitate (MP) in vitro, in addition to JHB(3) and JH III. Biosynthesized MP migrates on TLC and co-elutes from RP-18 HPLC with synthetic MP. Its identity is verified herein by GCMS. MP production is up-regulated twofold by mevastatin, an inhibitor of mevalonic acid-dependent isoprene biosynthesis. Fosmidomycin, an inhibitor of mevalonic acid-independent isoprene synthesis in graminaceous plants, up-regulates MP synthesis by about fourfold. However, it does not depress JHB(3) biosynthesis concurrently. This suggests that the initial enzyme(s) in the conversion of 1-deoxy-xylulose 5-phosphate to isoprene is presumably present in C. capitata, but is inhibited by fosmidomycin, and this inhibition diverts precursors to MP synthesis. Phytol, an acyclic diterpene, might be suppressing isoprene biosynthesis by CA, thereby resulting in a fourfold increase in the MP biosynthesis. Linolenic acid is an end-product and its presence in incubation media up-regulates MP biosynthesis by twofold, presumably due to the feedback diversion to biosynthesis of C(16:0) and its methyl ester. Biosynthesis of MP is markedly depressed after mating, while otherwise maintained at significantly higher levels in virgin females. MP biosynthesis is significantly reduced in virgin females by direct axonal control but is less consistent after mating.
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Biosynthetic maturation of the Corpus Allatum of the female adult medfly, Ceratitis capitata, and its putative control.
Journal of insect physiology, 2003Co-Authors: P Moshitzky, Lawrence I. Gilbert, Shalom W. ApplebaumAbstract:The major juvenile hormone (JH) homolog synthesized in vitro by the adult female Medfly (Ceratitis capitata) Corpus Allatum (CA) is JHB(3), with JH-III the minor homolog. Methyl-incorporation in vitro in post-eclosion virgin females is age-dependent. Basal activity occurs during the first four days post-eclosion and increases significantly thereafter, peaking at five days. Biosynthetic maturation of the mated female CA is delayed by one day and reduced considerably. The delayed response may be due to direct cerebral or neural inhibition. Synthetic Drosophila melanogaster sex peptide depresses JH biosynthesis by the Medfly female CA in vitro. Male-derived accessory gland peptides of the Medfly are transferred to the female during mating and a Medfly SP-analog may be responsible for down-regulation of JH synthesis by the CA in mated Medfly females. Mevinolin, an inhibitor of the mevalonate pathway, significantly reduces the biosynthesis of JHB(3), while farnesoic acid, a proximate precursor of JHIII, significantly stimulates the biosynthesis of both JHB(3) and JHIII in vitro.
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Sex‐peptide activates juvenile hormone biosynthesis in the Drosophila melanogaster Corpus Allatum
Archives of Insect Biochemistry and Physiology, 1996Co-Authors: Pnina Moshitzky, Irène Fleischmann, Nivi Chaimov, Philippe Saudan, Stefan Klauser, Eric Kubli, Shalom W. ApplebaumAbstract:Mating elicits two well-defined reactions in sexually matured females of many insects: reduction of receptivity and increased oviposition. These post-mating responses have been shown to be induced by factors synthesized in the reproductive tract of the adult male and transferred in the seminal fluid to the female during copulation. One of these factors, named sex-peptide (SP), has been identified in Drosophila melanogaster. Using an in vitro radiochemical assay, we show that synthetic sex-peptide considerably activates juvenile hormone III-bisepoxide (JHB3) synthesis in Corpus Allatum (CA) excised from Days 3 and 4 post-eclosion virgin females. Base levels are significantly lower at emergence (Day 0) than on subsequent days, and only weak stimulation is obtained on Day 1, while none is obtained on Day 2, where maximal basal synthesis occurs. The CA of mated females cannot be stimulated further for at least 7 days, but regain responsiveness by Day 10 after mating. Synthesis of JHB3 stimulated by SP in vitro persists for at least 4 h after removal of the peptide. Development of responsiveness of the CA to SP in vitro is compared with development of the post-mating reactions of sex-peptide injected virgin females. Our results suggest that the CA is a direct target for SP in vivo and that sexual maturity is established separately for the two post-mating reactions. © 1996 Wiley-Liss, Inc.
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sex peptide activates juvenile hormone biosynthesis in the drosophila melanogaster Corpus Allatum
Archives of Insect Biochemistry and Physiology, 1996Co-Authors: Pnina Moshitzky, Irène Fleischmann, Nivi Chaimov, Philippe Saudan, Stefan Klauser, Eric Kubli, Shalom W. ApplebaumAbstract:Mating elicits two well-defined reactions in sexually matured females of many insects: reduction of receptivity and increased oviposition. These post-mating responses have been shown to be induced by factors synthesized in the reproductive tract of the adult male and transferred in the seminal fluid to the female during copulation. One of these factors, named sex-peptide (SP), has been identified in Drosophila melanogaster. Using an in vitro radiochemical assay, we show that synthetic sex-peptide considerably activates juvenile hormone III-bisepoxide (JHB3) synthesis in Corpus Allatum (CA) excised from Days 3 and 4 post-eclosion virgin females. Base levels are significantly lower at emergence (Day 0) than on subsequent days, and only weak stimulation is obtained on Day 1, while none is obtained on Day 2, where maximal basal synthesis occurs. The CA of mated females cannot be stimulated further for at least 7 days, but regain responsiveness by Day 10 after mating. Synthesis of JHB3 stimulated by SP in vitro persists for at least 4 h after removal of the peptide. Development of responsiveness of the CA to SP in vitro is compared with development of the post-mating reactions of sex-peptide injected virgin females. Our results suggest that the CA is a direct target for SP in vivo and that sexual maturity is established separately for the two post-mating reactions. © 1996 Wiley-Liss, Inc.
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Pathway and regulation of JHIII-Bisepoxide biosynthesis in adult Drosophila melanogaster Corpus Allatum.
Archives of insect biochemistry and physiology, 1995Co-Authors: Pnina Moshitzky, Shalom W. ApplebaumAbstract:Adult female Drosophila melanogaster Corpus Allatum (CA) synthesize JHB3 from endogenous and exogenous precursors in vitro. We present evidence supporting the thesis that biosynthesis proceeds from precursor FA via initial epoxidation and terminal methylation on the basis of the following: (1) Methyl farnesoate is not epoxidized to JHIII or JHB3; (2) Authentic JHIII is not epoxidized to JHB3; and (3) FABE is markedly metabolized to JHB3. Cerebral allatostatic factors act at some stage subsequent to FA and this precursor is not normally rate-limiting. Additionally, neural inhibition from the brain acts at some biosynthetic step prior to FA. © 1995 Wiley-Liss, Inc.
Lawrence I. Gilbert - One of the best experts on this subject based on the ideXlab platform.
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Biosynthetic maturation of the Corpus Allatum of the female adult medfly, Ceratitis capitata, and its putative control.
Journal of insect physiology, 2003Co-Authors: P Moshitzky, Lawrence I. Gilbert, Shalom W. ApplebaumAbstract:The major juvenile hormone (JH) homolog synthesized in vitro by the adult female Medfly (Ceratitis capitata) Corpus Allatum (CA) is JHB(3), with JH-III the minor homolog. Methyl-incorporation in vitro in post-eclosion virgin females is age-dependent. Basal activity occurs during the first four days post-eclosion and increases significantly thereafter, peaking at five days. Biosynthetic maturation of the mated female CA is delayed by one day and reduced considerably. The delayed response may be due to direct cerebral or neural inhibition. Synthetic Drosophila melanogaster sex peptide depresses JH biosynthesis by the Medfly female CA in vitro. Male-derived accessory gland peptides of the Medfly are transferred to the female during mating and a Medfly SP-analog may be responsible for down-regulation of JH synthesis by the CA in mated Medfly females. Mevinolin, an inhibitor of the mevalonate pathway, significantly reduces the biosynthesis of JHB(3), while farnesoic acid, a proximate precursor of JHIII, significantly stimulates the biosynthesis of both JHB(3) and JHIII in vitro.
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An ultrastructural and developmental analysis of the Corpus Allatum of juvenile hormone deficient mutants ofDrosophila melanogaster
Roux's archives of developmental biology, 1993Co-Authors: Ji-da Dai, Lawrence I. GilbertAbstract:The ultrastructure of the Corpus Allatum of the apterous mutants ap ^4 and ap ^56f of Drosophila melanogaster during larval-pupal-adult metamorphosis and adult life was correlated with the gland's ability to synthesize juvenile hormone in vitro. During the early wandering period of the third instar of both mutants, a high concentration of smooth endoplasmic reticulum, mitochondria and mitochondrion-scalariform junction complexes are typical features of an active Corpus Allatum cell. Juvenile hormone biosynthesis by the glands is high at that time and, in fact, only slightly lower than that of wild type glands. In contrast to the wild type gland, the cells of the pupal and pharate adult Corpus Allatum of both mutants contains highly electron dense mitochondria with tubular cristae but no whorls of smooth endoplasmic reticulum nor glycogen clusters. The frequency and size of the lipid droplets, putatives depots of the juvenile hormone precursors, in cells of the ap ^56f gland is a function of the insect's age, but both are lower than in wild type gland cells. Juvenile hormone biosynthesis by both mutant glands remains at the basal level when compared to increased synthesis by the wild type gland. The frequency and density of lipid droplets in cells of the ap ^4 Corpus Allatum are much lower than in the ap ^56f glands. During adult life, the ultrastructural profile of the ap ^56f Corpus Allatum is similar to that of the wild type gland although the in vitro production of juvenile hormone by the former is much lower than that of the wild type gland. The ultrastructural features of the adult Corpus Allatum of ap ^4 homozygotes reveal precocious degeneration and support the view that this non-vitellogenic mutant is a juvenile hormone deficient mutation.
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Metamorphosis of the Corpus Allatum and degeneration of the prothoracic glands during the larval-pupal-adult transformation of Drosophila melanogaster: a cytophysiological analysis of the ring gland.
Developmental biology, 1991Co-Authors: Ji-da Dai, Lawrence I. GilbertAbstract:The degeneration of the prothoracic glands of Drosophila melanogaster during pupal-adult metamorphosis was analyzed by light microscopy, scanning, and transmission electron microscopy. The ultrastructural observations were correlated with the ability of the ring gland to synthesize ecdysteroids in vitro. The ring gland is prominent during larval life and is identifiable until just before adult eclosion but undergoes dramatic changes in location, shape, size, ultrastructure, and function during pupal-adult development. Prothoracic gland degeneration is characterized by: a gradual decrease in its ability to synthesize ecdysteroids; a decreasing quantity of smooth endoplasmic reticulum (SER) and mitochondria; the absence of intercellular channels; cytoplasmic fragmentation; and the separation of the prothoracic gland from the Corpus Allatum and Corpus cardiacum. An ultrastructural analysis of the Corpus Allatum during larval-pupal-adult metamorphosis and adult life was also correlated with function, i.e., juvenile hormone biosynthesis, using a radiochemical assay of ring glands and adult corpora allata in vitro. A relatively high concentration of SER, mitochondria, and mitochondrion-scalariform junction complexes are typical features of an active Corpus Allatum cell. The migration of the Corpus Allatum from the ring gland to its position as a separate gland in the adult fly was studied in detail. The capacity of the Corpus Allatum to synthesize juvenile hormone is at its peak in the ring gland of the early wandering third instar larva, whereas the Corpus Allatum of 2-day-old female adults displayed the greatest synthetic activity during adult life. The physiological significance of the alterations in gland activity is discussed.
Ann-shyn Chiang - One of the best experts on this subject based on the ideXlab platform.
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nadph diaphorase activity in Corpus Allatum cells of the cockroach diploptera punctata
Insect Biochemistry and Molecular Biology, 2000Co-Authors: Ann-shyn Chiang, Chih-yung Lin, Chihjen Wen, Chienhung YehAbstract:Using the fixation insensitive NADPH-diaphorase reaction as a histochemical marker for the enzyme nitric oxide synthase (NOS), we investigated the possible sites of putatively NOS-related NADPH-diaphorase in the brain and retrocerebral complex of the cockroach, Diploptera punctata. In the cerebral ganglion, NADPH-diaphorase expression was localized in antennal lobes, optic lobes, mushroom bodies and neurosecretory cells. The highest NADPH activity was detected in the corpora allata (CA). Spectrophotometric quantitation indicated that NADPH-diaphorase activity first increased and then decreased (cycled) in the CA of mated females. In addition, during the first ovarian cycle, NADPH-diaphorase activity fluctuated concurrently with cyclic changes in the size of Corpus Allatum cells. In virgin females, NADPH-diaphorase activity remained at a low level, but it increased if the neural connectives between CA and brain were severed, indicating that the brain inhibited NADPH-diaphorase expression in the CA. Although nerve terminals were abundant in the CA, NADPH-diaphorase was clearly endogenous and synthesized by glandular cells, as was shown by histochemical staining of the cytosol in all dissociated cells of the CA. We have also demonstrated NADPH-diaphorase activity in the CA of the American cockroach Periplaneta americana, the house cricket Acheta domesticus, the lepidopteran Leucania loreyi, and the fruit fly Drosophila melanogaster, suggesting that NOS occurs in the CA of most, if not all insects. It is therefore possible that Corpus Allatum cells release NO, along with juvenile hormone, which presumably can function as a messenger molecule.
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glutamate induced rise in cytosolic calcium concentration stimulates in vitro rates of juvenile hormone biosynthesis in Corpus Allatum of diploptera punctata
Molecular and Cellular Endocrinology, 1999Co-Authors: Maciej A Pszczolkowski, Hsin Ping Liu, Weishiang Lee, Ann-shyn ChiangAbstract:Abstract We show that in a cockroach, Diploptera punctata, endocrine function of the Corpus Allatum may be modulated by l -glutamate, a major fast excitatory neurotransmitter in the central nervous system of vertebrates and invertebrates. The widely accepted concept that synthesis of juvenile hormone (JH) depends upon intracellular calcium concentration, is extended by the finding that 60 and 100 μM l -glutamate induces both an increase in calcium concentration in the cytosol of Corpus Allatum cells, and stimulates JH synthesis in vitro. We show that l -glutamate stimulates JH synthesis by inducing calcium influx since in calcium-free medium the stimulatory effect is not observed. Furthermore, the non-specific glutamate-receptor antagonist, 100 μM kynurenate, and 1.8 mM magnesium, inhibit the stimulatory effect of l -glutamate on JH synthesis in vitro. These results suggest that functional ionotropic glutamate receptors are present on the surface of the cells in Corpus Allatum, and that rates of JH are at least in part regulated via these receptors.
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Juvenile hormone synthesis in relation to Corpus Allatum development in embryos ofthe viviparous cockroach
1998Co-Authors: Glenn L. Holbrook, Ann-shyn Chiang, Yuan-ju Lee, Chih-yung Lin, Coby SchalAbstract:Summary Few studies have addressed endocrinology ofthe corpora allata (CA) in insect embryos. We now report on development and biosynthetic activity of CA in embryos of a viviparous cockroach, Diploptera punctata. When newly-eclosed adult females of D. punctata were mated, they oviposited and gave birth, respectively, about 8 and 73 days later; thus, gestation and corresponding embryogenesis lasted approximately 65 days. Dorsal closure, which coincides with differentiation of the CA, was concluded when embryos were about 13 days old and had completed 20% of embryogenesis. Reverse phase-high performance liquid chromatography revealed that embryonic CA released predominantly juvenile hormone III (JH) in vitro. Furthermore, an in vitro radiochemical assay showed that between day 28 of embryogenesis (43% of embryonic development completed) and hatch rates ofJH synthesis rose, plateaued and then fell. When CA activity was increasing or was high, from day 28 to 54 (83% development), mitosis occurred at low and constant rates within embryonic CA, and Corpus Allatum cell number increased gradually. Between days 56 (86% development) and 60 (92% development), CA activity fell to a low level, rates of mitosis peaked, and Corpus Allatum cell number rose rapidly. Throughout embryogenesis, CA volume increased in parallel with CA cell number, suggesting that glandular growth was due largely to cell proliferation. Although CA activity and volume changed considerably in embryos, the diameter of Corpus Allatum cells, as measured from enzymatically dissociated CA, remaind surprisingly constant at 11-12,um on days 32, 46 and 60 (49, 71 and 92% development). Ultrastrucarral observations confIrmed the large size of cells in low-activity CA of 60-day-old embryos and also showed that these cells, like those in highly active CA of 46-day-old embryos, contained abundant cytoplasm, ribosomes, microtubules and mitochondria.
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Ovarian regulation of cyclic changes in size and activity of Corpus Allatum cells in Blattella germanica
Journal of Insect Physiology, 1991Co-Authors: Ann-shyn Chiang, Edina L. Burns, Coby SchalAbstract:The roles of the ovary and egg case in the regulation of the development and activity of the corpora allata were studied in Blattella germanica adult females. The corpora allata of ovariectomized females exhibit a delayed pattern of development and activity compared with intact females. Implantation of a young ovary into ovariectomized females resulted in a faster activation of the corpora allata to the same peak juvenile hormone biosynthetic rates exhibited by intact females. Injection of 20-hydroxyecdysone caused transient declines in both the activity and the size of Corpus Allatum cells. Insertion of a waxed egg case into the genital atrium of ovariectomized females, with or without injection of 20-hydroxyecdysone, mimicked the 21-day pregnancy in intact females and caused Corpus Allatum cells to become small and inactive. The size and activity of Corpus Allatum cells increased again when the inserted egg case was removed manually or had been carried by the ovariectomized female for more than 3 weeks. In both intact and ovariectomized females, the activity of the corpora allata, as measured by the spontaneous and farnesoic acid-stimulated rates of juvenile hormone biosynthesis, and Corpus Allatum development, as reflected by the size of cells, always exhibited the same patterns and responded concurrently to the various ovarian factors. These results indicate that ovarian factors, both stimulatory and inhibitory, regulate juvenile hormone production mainly by inducing changes in the cellular machinery rather than in rate-limiting enzymes.
Maciej A Pszczolkowski - One of the best experts on this subject based on the ideXlab platform.
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chilling stress effects on Corpus Allatum proliferation in the hawaiian cockroach diploptera punctata a role for ecdysteroids
Journal of Insect Physiology, 2004Co-Authors: Maciej A Pszczolkowski, Dale B GelmanAbstract:Endocrine regulation of Corpus Allatum (CA) cell proliferation in response to chilling was studied in mated females of the Hawaiian cockroach, Diploptera punctata. Chilling alone, when applied 24 h post-mating, suppressed CA cell division, and elevated ecdysteroid levels in Diploptera’s haemolymph. Application of 20-hydroxyecdysone (20E) at 24 h post-mating similarly suppressed CA cell division, but had no effects at 48 h or 72 h post-mating. Severance of the ventral nerve cord prior to chilling or to the application of 20E prevented suppression of CA cell division, indicating that the effects of either chilling or 20E application are mediated by the ventral nerve cord.
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glutamate induced rise in cytosolic calcium concentration stimulates in vitro rates of juvenile hormone biosynthesis in Corpus Allatum of diploptera punctata
Molecular and Cellular Endocrinology, 1999Co-Authors: Maciej A Pszczolkowski, Hsin Ping Liu, Weishiang Lee, Ann-shyn ChiangAbstract:Abstract We show that in a cockroach, Diploptera punctata, endocrine function of the Corpus Allatum may be modulated by l -glutamate, a major fast excitatory neurotransmitter in the central nervous system of vertebrates and invertebrates. The widely accepted concept that synthesis of juvenile hormone (JH) depends upon intracellular calcium concentration, is extended by the finding that 60 and 100 μM l -glutamate induces both an increase in calcium concentration in the cytosol of Corpus Allatum cells, and stimulates JH synthesis in vitro. We show that l -glutamate stimulates JH synthesis by inducing calcium influx since in calcium-free medium the stimulatory effect is not observed. Furthermore, the non-specific glutamate-receptor antagonist, 100 μM kynurenate, and 1.8 mM magnesium, inhibit the stimulatory effect of l -glutamate on JH synthesis in vitro. These results suggest that functional ionotropic glutamate receptors are present on the surface of the cells in Corpus Allatum, and that rates of JH are at least in part regulated via these receptors.
Coby Schal - One of the best experts on this subject based on the ideXlab platform.
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Juvenile hormone synthesis in relation to Corpus Allatum development in embryos ofthe viviparous cockroach
1998Co-Authors: Glenn L. Holbrook, Ann-shyn Chiang, Yuan-ju Lee, Chih-yung Lin, Coby SchalAbstract:Summary Few studies have addressed endocrinology ofthe corpora allata (CA) in insect embryos. We now report on development and biosynthetic activity of CA in embryos of a viviparous cockroach, Diploptera punctata. When newly-eclosed adult females of D. punctata were mated, they oviposited and gave birth, respectively, about 8 and 73 days later; thus, gestation and corresponding embryogenesis lasted approximately 65 days. Dorsal closure, which coincides with differentiation of the CA, was concluded when embryos were about 13 days old and had completed 20% of embryogenesis. Reverse phase-high performance liquid chromatography revealed that embryonic CA released predominantly juvenile hormone III (JH) in vitro. Furthermore, an in vitro radiochemical assay showed that between day 28 of embryogenesis (43% of embryonic development completed) and hatch rates ofJH synthesis rose, plateaued and then fell. When CA activity was increasing or was high, from day 28 to 54 (83% development), mitosis occurred at low and constant rates within embryonic CA, and Corpus Allatum cell number increased gradually. Between days 56 (86% development) and 60 (92% development), CA activity fell to a low level, rates of mitosis peaked, and Corpus Allatum cell number rose rapidly. Throughout embryogenesis, CA volume increased in parallel with CA cell number, suggesting that glandular growth was due largely to cell proliferation. Although CA activity and volume changed considerably in embryos, the diameter of Corpus Allatum cells, as measured from enzymatically dissociated CA, remaind surprisingly constant at 11-12,um on days 32, 46 and 60 (49, 71 and 92% development). Ultrastrucarral observations confIrmed the large size of cells in low-activity CA of 60-day-old embryos and also showed that these cells, like those in highly active CA of 46-day-old embryos, contained abundant cytoplasm, ribosomes, microtubules and mitochondria.
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Ovarian regulation of cyclic changes in size and activity of Corpus Allatum cells in Blattella germanica
Journal of Insect Physiology, 1991Co-Authors: Ann-shyn Chiang, Edina L. Burns, Coby SchalAbstract:The roles of the ovary and egg case in the regulation of the development and activity of the corpora allata were studied in Blattella germanica adult females. The corpora allata of ovariectomized females exhibit a delayed pattern of development and activity compared with intact females. Implantation of a young ovary into ovariectomized females resulted in a faster activation of the corpora allata to the same peak juvenile hormone biosynthetic rates exhibited by intact females. Injection of 20-hydroxyecdysone caused transient declines in both the activity and the size of Corpus Allatum cells. Insertion of a waxed egg case into the genital atrium of ovariectomized females, with or without injection of 20-hydroxyecdysone, mimicked the 21-day pregnancy in intact females and caused Corpus Allatum cells to become small and inactive. The size and activity of Corpus Allatum cells increased again when the inserted egg case was removed manually or had been carried by the ovariectomized female for more than 3 weeks. In both intact and ovariectomized females, the activity of the corpora allata, as measured by the spontaneous and farnesoic acid-stimulated rates of juvenile hormone biosynthesis, and Corpus Allatum development, as reflected by the size of cells, always exhibited the same patterns and responded concurrently to the various ovarian factors. These results indicate that ovarian factors, both stimulatory and inhibitory, regulate juvenile hormone production mainly by inducing changes in the cellular machinery rather than in rate-limiting enzymes.
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Developmental regulation of juvenile hormone synthesis: ovarian synchronization of volumetric changes of Corpus Allatum cells in cockroaches.
Molecular and cellular endocrinology, 1991Co-Authors: Chiang Ann-shyn, Edina L. Burns, Michal Gadot, Coby SchalAbstract:The Corpus Allatum (CA) cells of adult Blattella germanica females undergo cyclic volumetric changes in relation to juvenile hormone (JH) synthesis. In intact females the size of CA cells changes synchronously during the gonotrophic cycle, resulting in cyclic JH synthesis. In ovariectomized females volumetric changes among CA cells become asynchronous, resulting in highly variable but high rates of JH synthesis. Injection of the steroid hormone 20-hydroxyecdysone into ovariectomized females with active CA resulted in a transient decline followed by an increase in both CA volume and JH biosynthesis. This response was due to a change in the size distribution of CA cells and not in the total number of CA cells. In ovariectomized females, CA cells can be re-synchronized into a uniform population of small inactive cells with injection of 20-hydroxyecdysone and implantation of an artificial egg-case, mimicking the successive events of ovulation, oviposition and pregnancy.
