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Insects Sep 2021Arthropods, including insects, convert sterols into cholesterol due to the inability to synthesise cholesterol de novo. 24-dehydrocholesterol reductase (DHCR24) plays an...
Arthropods, including insects, convert sterols into cholesterol due to the inability to synthesise cholesterol de novo. 24-dehydrocholesterol reductase (DHCR24) plays an important role in the conversion. Not only involving the cholesterol biosynthesis in vertebrates, DHCR24 is required for the conversion of desmosterol into cholesterol in phytophagous insects. The current study extensively examined DHCR24 in omnivorous insects, which feed on both plants and animals, using as the experimental model. We identified cDNAs encoding two homologues of DHCR24 from , which were designated as GbDHCR24-1 and GbDHCR24-2. Both homologues contained the flavin adenine dinucleotide binding domain, which is a feature of DHCR24. Quantitative polymerase chain reaction revealed that among tissues of adult crickets, fat body and anterior midgut expressed high levels of GbDHCR24s. Both fat body and anterior midgut demonstrated DHCR24 activities in which one of the functions is the conversion of desmosterol into cholesterol in vitro. Knockdown of GbDHCR24-1 significantly reduced the conversion activity in the anterior midgut while knockdown of the GbDHCR24-2 did not. Additionally, the accumulation of desmosterol was detected in a feeding experiment with a specific DHCR24 inhibitor, azacosterol. We finally concluded that GbDHCR24-1 is the major enzyme that facilitates the desmosterol-to-cholesterol-conversion in crickets.
PubMed: 34564222
DOI: 10.3390/insects12090782 -
Journal of Chromatography. B,... Oct 2017Wildlife contraceptives are an emerging tool for minimizing human-wildlife conflicts. One promising avian contraceptive compound, 20,25-diazacholesterol (DAC), reduces...
Wildlife contraceptives are an emerging tool for minimizing human-wildlife conflicts. One promising avian contraceptive compound, 20,25-diazacholesterol (DAC), reduces fertility by inhibiting cholesterol synthesis. A reliable analytical method for DAC was required in support of its registration for use as a reproductive control agent in pest bird species. A liquid chromatographic method employing tandem mass spectrometry (LC-MS/MS) was developed for the analysis of tissue extracts following solid phase extraction clean-up. Tissues analyzed were whole body samples from crows, monk parakeets, and quails and liver samples from crows and quails. Excellent sensitivity and selectivity was afforded by tandem mass spectrometry. The method accuracy of DAC from various tissue samples fortified at parts-per-million (ppm) and parts-per-billion (ppb) concentrations was high (>90%) with excellent precision (<10% relative standard deviation). Lower limits of detection were excellent in all tissues types, ranging from 1 to 11ppb in whole body matrices and 9.9-34ppb in liver matrices.
Topics: Animals; Azacosterol; Birds; Chromatography, High Pressure Liquid; Contraceptive Agents; Limit of Detection; Linear Models; Liver; Pest Control; Reproducibility of Results; Solid Phase Extraction; Tandem Mass Spectrometry; Tissue Distribution
PubMed: 28985619
DOI: 10.1016/j.jchromb.2017.09.028 -
Integrative Zoology Dec 2011Grey squirrels (Sciurus carolinensis) are an invasive species in Britain and Italy. They have replaced native red squirrels (Sciurus vulgaris) throughout most of...
Grey squirrels (Sciurus carolinensis) are an invasive species in Britain and Italy. They have replaced native red squirrels (Sciurus vulgaris) throughout most of Britain, and cause damage to trees. Currently, lethal control is used to manage grey squirrel populations in Britain, but nonlethal methods might be more acceptable to the public. One such method is contraception with 20,25-diazacholesterol dihydrochloride (DiazaCon™). DiazaCon™ inhibits the conversion of desmosterol to cholesterol, resulting in increasing desmosterol concentrations and decreasing cholesterol concentrations. Because cholesterol is needed for the synthesis of steroid reproductive hormones, such as progesterone and testosterone, inhibition of cholesterol synthesis indirectly inhibits reproduction. Desmosterol is used as a marker of efficacy in laboratory studies with species that do not reproduce readily in captivity. Grey squirrels were gavaged with a DiazaCon™ solution for 2 days, and then fed DiazaCon™-coated peanuts for an additional 8 days at target doses of 50 and 100 mg DiazaCon™ per kg body weight. There was a significant difference in cholesterol concentrations in the treatment groups compared to the control group. Cholesterol was reduced by ≥ 40% for 2 months in both treatment groups. There were no differences among groups with respect to blood chemistry and hematology parameters, and mean values are reported. The mean overall dose of DiazaCon™ received was 29.0 ± 1.6 and 55.3 ± 4.3 mg/kg in the low (50 mg/kg) and high dose (100 mg/kg) groups, respectively. DiazaCon™ might provide an effective, acceptable alternative to lethal control.
Topics: Animals; Azacosterol; Blood Chemical Analysis; Cholesterol; Contraceptive Agents; Desmosterol; Dose-Response Relationship, Drug; England; Hematologic Tests; Introduced Species; Sciuridae
PubMed: 22182332
DOI: 10.1111/j.1749-4877.2011.00247.x -
Poultry Science Feb 2004Contraception may provide a useful nonlethal management tool when it is desirable to reduce populations of birds. We tested the efficacy of 20,25 diazacholesterol, and...
Effectiveness of twenty, twenty-five diazacholesterol, avian gonadotropin-releasing hormone, and chicken riboflavin carrier protein for inhibiting reproduction in Coturnix quail.
Contraception may provide a useful nonlethal management tool when it is desirable to reduce populations of birds. We tested the efficacy of 20,25 diazacholesterol, and immunization with avian gonadotropin-releasing hormone (AGnRH-I) and chicken riboflavin carrier protein (cRCP) as contraceptives and investigated their modes of action in Coturnix quail (Coturnix coturnix japonica). Females that were paired with males treated with 20,25 diazacholesterol produced lower percentages of eggs that were fertile and hatched. Females treated with 20,25 diazacholesterol and paired with control males laid fewer eggs, and lower percentages of their eggs were fertile and hatched. Treatment with 20,25 diazacholesterol reduced testosterone levels in males and progesterone levels in females. Nonesterified cholesterol levels were reduced, whereas desmosterol levels increased in birds treated with 20,25 diazacholesterol. Treatment with AGnRH-I and cRCP immunocontraceptive vaccines did not decrease average egg production and hatchability or hormone levels, but this failure might have been due to the vaccination protocol. If registered, wildlife managers may be able to use 20,25 diazacholesterol when other methods, such as lethal control, are undesirable for reducing damage caused by specific breeding behaviors such as the building of nests.
Topics: Animals; Anticholesteremic Agents; Azacosterol; Carrier Proteins; Cholesterol; Contraceptive Agents; Coturnix; Desmosterol; Female; Fertility; Gonadotropin-Releasing Hormone; Male; Membrane Transport Proteins; Oviposition; Progesterone; Riboflavin; Testosterone; Treatment Outcome
PubMed: 14979575
DOI: 10.1093/ps/83.2.234 -
Reproductive Toxicology (Elmsford, N.Y.) 2003The effect of intraperitoneal administration for 28 days of 10, 20, and 30 mg/kg body weight per day of 20,25-diazacholesterol dihydrochloride (SC 12937), a...
The effect of intraperitoneal administration for 28 days of 10, 20, and 30 mg/kg body weight per day of 20,25-diazacholesterol dihydrochloride (SC 12937), a hypocholesterolemic agent, on the testis of Parkes (P) strain mice was investigated. Histologically, testes in mice treated with 10 or 20 mg/kg body weight of SC 12937 showed non-uniform degenerative changes in the seminiferous tubules as both affected and normal tubules were observed in the same section; the affected tubules showed intraepithelial vacuolation, occurrence of giant cells, exfoliation of germ cells, and marginal condensation of chromatin in round spermatids. In both dosage groups, only 11-12% of the seminiferous tubules were affected, and no significant differences were found in the frequency of affected tubules between the two groups. By contrast, testes in mice treated with 30 mg/kg body weight of the drug exhibited a degenerated appearance of germ cells in all seminiferous tubules. The treatment also had adverse effects on motility, viability, morphology, and number of spermatozoa in the cauda epididymidis, and on fertility. Even 56 days after drug withdrawal, the above parameters remained markedly affected. Our results thus suggest that SC 12937 treatment causes antispermatogenic and antifertility effects in P mice and that the effects are not reversible up to 56 days after drug withdrawal. This compound may prove useful in the control of rodent populations.
Topics: Animals; Anticholesteremic Agents; Azacosterol; Chemosterilants; Dose-Response Relationship, Drug; Fertility; Injections, Intraperitoneal; Male; Mice; Mice, Inbred Strains; Models, Animal; Seminiferous Epithelium; Sperm Motility; Spermatogenesis; Spermatozoa
PubMed: 12507656
DOI: 10.1016/s0890-6238(02)00075-8 -
Journal of Agricultural and Food... Jan 200320,25-Diazacholesterol is being evaluated as a contraceptive for the nonlethal control of avian and mammalian wildlife pests. The identification of an analyte in blood...
20,25-Diazacholesterol is being evaluated as a contraceptive for the nonlethal control of avian and mammalian wildlife pests. The identification of an analyte in blood which was highly correlated with absorbed dose and efficacy is valuable for determining effective formulations and dosing variables. Such an analyte or biomarker is also valuable for determining the percentage of pest populations that consume an effective dose of the active ingredient in the field. HPLC analyses of blood collected from dosed animals failed to detect 20,25-diazacholesterol but indicated that levels of free cholesterol and related compounds were affected by 20,25-diazacholesterol absorption. The greatest percent change in chromatographic peak area associated with 20,25-diazacholesterol administration was observed for desmosterol, a cholesterol precursor. 20,25-Diazacholesterol appeared to block the conversion of desmosterol to cholesterol, resulting in an elevated concentration of the precursor. The elevation of blood desmosterol levels is being used as an indicator of 20,25-diazacholesterol absorption and to facilitate the development of a 20,25-diazacholesterol-based contraceptive for pest wildlife.
Topics: Animals; Azacosterol; Biomarkers; Chromatography, High Pressure Liquid; Contraceptive Agents; Coturnix; Deer; Desmosterol; Female; Gas Chromatography-Mass Spectrometry; Male; Pest Control
PubMed: 12502398
DOI: 10.1021/jf020731d -
Journal of AOAC International 2001Liquid chromatographic (LC) methods were developed for quantitating the potential avian contraceptive DiazaCon in quail feed and serum. DiazaCon was extracted from...
Liquid chromatographic (LC) methods were developed for quantitating the potential avian contraceptive DiazaCon in quail feed and serum. DiazaCon was extracted from ground quail feed with basic n-butyl chloride. The n-butyl chloride extract was evaporated to dryness. The DiazaCon residues were dissolved in an aqueous methanolic ion pairing solution and quantitated by LC at 206 nm. Avian sera was combined with an equal volume of a pH 4 aqueous solution of ion pairing reagent and filtered to remove interfering proteins. DiazaCon was quantitated by LC. Mean recoveries for 500 and 2000 ppm fortified feed were 89.1 and 91.0%, respectively. The mean recovery for sera fortified at 5 levels ranging from 35 to 2000 ppm was 84.9%. Method limits of detection were approximately 14 and 13 ppm for feed and sera, respectively.
Topics: Animal Feed; Animals; Azacosterol; Chromatography, High Pressure Liquid; Contraceptive Agents; Coturnix; Hydrogen-Ion Concentration; Indicators and Reagents; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Quality Control
PubMed: 11417624
DOI: No ID Found -
Bioorganic & Medicinal Chemistry May 2001A number of aza-steroids were synthesized as potent phosphatidylinositol phospholipase C (PI-PLC) inhibitors. The epimeric mixtures 22,25-diazacholesterol (8a) and...
A number of aza-steroids were synthesized as potent phosphatidylinositol phospholipase C (PI-PLC) inhibitors. The epimeric mixtures 22,25-diazacholesterol (8a) and 3beta-hydroxy-22,25-diazacholestane (8b) were among the most active of these inhibitors, with IC(50) values of 7.4 and 7.5 microM, respectively. The 20alpha epimer, 8a2 (IC(50)=0.64 microM), whose stereochemistry at C-20 coincides with that of cholesterol, was found 50 times more potent than the 20beta epimer, 8a1 (IC(50)=32.2 microM). In diaza-estrone derivatives, the 3-methoxy group on the aromatic A-ring of 23 exhibited moderate PI-PLC inhibitory activity (IC(50)=19.7 microM), while compound with a free hydroxyl group (21) was inactive. However, in diaza-pregnane derivatives, epimers with a 3-hydroxyl group (8a, IC(50)=7.4 microM) exhibited more potent PI-PLC inhibitory activity than their counterparts with 3-methoxyl group on the non-aromatic A-ring (26, IC(50)=17.4 microM). We have illustrated in our previous publication that 3-hydroxyl-6-aza steroids are potent PI-PLC inhibitors.(3) However, simultaneous presence of the 6-aza and 22,25-diaza moieties in one molecule as in 13, led to loss of activity. Epimeric mixture 8a showed selective growth inhibition effects in the NCI in vitro tumor cell screen with a mean GI(50) value (MG-MID) of 5.75 microM for 54 tumors.
Topics: Azacosterol; Azasteroids; Cholestanols; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; Inhibitory Concentration 50; Phosphatidylinositol Diacylglycerol-Lyase; Phosphoinositide Phospholipase C; Structure-Activity Relationship; Tumor Cells, Cultured; Type C Phospholipases
PubMed: 11377165
DOI: 10.1016/s0968-0896(00)00302-3 -
European Journal of Pharmacology Apr 1993It has been reported that an enantiomer ((S)-(-)-4) of clofibric acid, and the racemate, can block the chloride conductance of skeletal muscle membrane. It has also been...
It has been reported that an enantiomer ((S)-(-)-4) of clofibric acid, and the racemate, can block the chloride conductance of skeletal muscle membrane. It has also been reported that several analogs of clofibric acid inhibit the HCO3(-)-Cl- exchange of erythrocytes. Since the two effects are probably similar biophysical membrane phenomena, the possibility of a common molecular mechanism arises. We exposed Sprague-Dawley male rats to long-term administration of clofibrate and 20,25-diazacholesterol (20,25-D) for comparison, at equipotent doses. Clofibrate (but not 20,25-diazacholesterol) produced a significant increase in density of the 220,000 Da band (beta-spectrin) and a decrease, also significant, in density of bands 2.1, 2.2, 2.3, 2.6 (syndeins or ankyrins) and of bands 4.1 and 6. Thus, clofibrate exhibits a manifold effect on the protein profile of the erythrocyte membrane cytoskeleton which, due to the lack of effect of 20-25-D, does not seem to be produced by the hypolipidemic effect per se, and thus deserves further study.
Topics: Animals; Azacosterol; Blood Proteins; Cholesterol; Clofibrate; Cytoskeleton; Densitometry; Erythrocyte Membrane; Indicators and Reagents; Male; Microscopy, Electron, Scanning; Osmotic Fragility; Rats; Rats, Sprague-Dawley
PubMed: 8491258
DOI: 10.1016/0922-4106(93)90115-p -
Carcinogenesis Sep 1990The metabolism of zymosterol and mevalonic acid was studied in vitro using the skin homogenates of 3-methylcholanthrene (3MC), diazacholesterol-treated and untreated...
The metabolism of zymosterol and mevalonic acid was studied in vitro using the skin homogenates of 3-methylcholanthrene (3MC), diazacholesterol-treated and untreated mice. In normal mouse skin only lathosterol was a major metabolite and the other metabolites, cholesta-5,7,24-trien-3 beta-ol, desmosterol, cholesterol and 7-dehydrocholesterol were much less abundant. However, in the skin homogenate of mice treated with 3MC lathosterol production was depressed, while the production of cholesta-5,7,24-trien-3 beta-ol and desmosterol was significantly increased, the cholesterol level being normal or a little higher. In contrast, in the skin homogenate of mice administered diazacholesterol the production of both lathosterol and cholesterol was almost completely blocked with the slightly increased production of cholesta-5,7,24-trien-3 beta-ol and desmosterol. The metabolism in vitro of [2-14C]-mevalonic acid was quite similar to that of zymosterol, and no additional product which might possibly have been produced by the Kandutsch-Russell pathway was observed. Two pathways for cholesterol biosynthesis, therefore, may exist in mouse skin; the first is lanosterol----zymosterol----5 alpha-cholesta-7,24-dien-3 beta-ol----lathosterol----7-dehydrocholesterol----cholesterol, and the second by Bloch: lanosterol----zymosterol----5 alpha-cholesta-7,24-dien-3 beta-ol----cholesta-5,7,24-trien-3 beta-ol----desmosterol----cholesterol. When mouse skin is treated with 3-MC the former pathway is virtually blocked and the latter is stimulated, keeping the level of cholesterol in the tissue constant or a little higher than normal, which seems to be a significant change in the early stage of chemical carcinogenesis.
Topics: Animals; Azacosterol; Carcinogens; Cholesterol; Male; Methylcholanthrene; Mevalonic Acid; Mice; Mice, Inbred ICR; Radioisotope Dilution Technique; Reference Values; Skin; Sterols; Tritium
PubMed: 2205410
DOI: 10.1093/carcin/11.9.1647