Chronic GnRH administration in prepubertal male pigs

1988 ◽  
Vol 118 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Grietje Dijkstra ◽  
J. Martje Fentener van Vlissingen ◽  
C. J. G. Wensing ◽  
P. M. M. van Dorst-Bruijns ◽  
H.J. Degenhart ◽  
...  

Abstract. The effect of chronic pulsatile low-dose GnRH treatment on the juvenile testis and associated structures was evaluated in relation to hormonal parameters in the peripheral blood in the pig. Starting at 8 weeks of age, male pigs (crossbreds of Dutch Landrace and Yorkshire breeds) were injected 6 times daily im with 0, 75 or 250 ng GnRH/kg body weight during 4 weeks. Immediately after the treatment period, a GnRH stimulation test with 750 ng GnRH/kg iv was carried out. Samples for plasma LH, FSH, testosterone and 5αDHT measurement were obtained weekly (basal level) and after GnRH stimulation. The pigs were castrated at 12 weeks of age and the weights and lengths of the testis, epididymis and cremaster muscle were recorded. Intratesticular testosterone and 5αDHT concentrations were determined, and the testis and epididymis were evaluated for histological changes. Basal plasma hormone concentrations, intratesticular androgen concentrations and the response of the pituitary gland to stimulation had not been affected by GnRH treatment. Pigs receiving the higher treatment dose of GnRH showed less increase in testosterone levels in response to the stimulation dose at 12 weeks of age than the other pigs. Morphologically, no changes were observed in the epididymis and cremaster muscle after GnRH treatment and no signs of reactivation of structures that can provoke testicular descent could be seen. The development of the seminiferous epithelium was more advanced in the GnRH-treated groups, apparently in a dose-dependent manner.

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 723
Author(s):  
Jiang Ma ◽  
Mi Li ◽  
Na Li ◽  
Wood Yee Chan ◽  
Ge Lin

Pyrrolizidine alkaloids (PAs) with 1,2-unsaturated necine base are hepatotoxic phytotoxins. Acute PA intoxication is initiated by the formation of adducts between PA-derived reactive pyrrolic metabolites with cellular proteins. The present study aimed to investigate the correlation between the formation of hepatic pyrrole–protein adducts and occurrence of PA-induced liver injury (PA-ILI), and to further explore the use of such adducts for rapidly screening the hepatotoxic potency of natural products which contain PAs. Aqueous extracts of Crotalaria sessiliflora (containing one PA: monocrotaline) and Gynura japonica (containing two PAs: senecionine and seneciphylline) were orally administered to rats at different doses for 24 h to investigate PA-ILI. Serum alanine aminotransferase (ALT) activity, hepatic glutathione (GSH) level, and liver histological changes of the treated rats were evaluated to assess the severity of PA-ILI. The levels of pyrrole–protein adducts formed in the rats’ livers were determined by a well-established spectrophotometric method. The biological and histological results showed a dose-dependent hepatotoxicity with significantly different toxic severity among groups of rats treated with herbal extracts containing different PAs. Both serum ALT activity and the amount of hepatic pyrrole–protein adducts increased in a dose-dependent manner. Moreover, the elevation of ALT activity correlated well with the formation of hepatic pyrrole–protein adducts, regardless of the structures of different PAs. The findings revealed that the formation of hepatic pyrrole–protein adducts—which directly correlated with the elevation of serum ALT activity—was a common insult leading to PA-ILI, suggesting a potential for using pyrrole–protein adducts to screen hepatotoxicity and rank PA-containing natural products, which generally contain multiple PAs with different structures.


2021 ◽  
Author(s):  
Jianguo Li ◽  
Zhen Li ◽  
Zefeng Gao ◽  
Juan Xia ◽  
Jia Cui ◽  
...  

Abstract Vitamin D was empirically applied for Tuberculosis (TB) treatment in the past, and is currently used as an adjuvant for TB therapy. Although an increasing pile of evidences suggests that vitamin D has no therapeutic effect against TB infection, the prophylactic effect of vitamin D in preventing TB remains largely undetermined. To experimentally valuate the potential prophylactic effect of calcitriol (the active form of vitamin D) against mycobacterium infection, we performed dose-gradient calcitriol soaking in 30-day-old zebrafish before Mycobacterium marinum (M. marinum) challenge through tail vein injection. 1H-NMR metabolomics analysis was further performed for illustration of potential mechanisms underlying the prophylactic effect of calcitriol against M. marinum. The results suggested that calcitriol exerts dose-dependent prophylactic anti-mycobacterium effects, i.e., the bacterial load and the corresponding inflammatory factors (IL-1β, TNF-α, and IFN-γ) expressions in M. marinum challenged zebrafish were reduced by low-dose (25 µg/L) or high-dose (2500 µg/L) calcitriol soaking, rather than by moderate-dose (250 µg/L) calcitriol soaking. Body weight of the M. marinum challenged zebrafish was recovered by high-dose prophylactic calcitriol soaking rather than by low-dose or moderate-dose calcitriol. The 1H-NMR metabolomic profiling identified 29 metabolites with altered abundance among the dose-gradient calcitriol groups, among which 22 metabolites were co-varied with the dose of calcitriol, the rest 7 metabolites were co-varied with the bacterial load and the inflammatory response in term of cytokine expression. Further pathway analysis indicated that the glycine, serine, and threonine metabolism pathway was the activated in both of the two metabolite groups, indicating that the pathway was altered by dose-gradient of calcitriol and was in response to M. marinum infection in zebrafish. The results of the present study suggested that the activation of glycine, serine and threonine metabolism pathway may play a potential role for the dose-dependent anti-mycobacterium effect induced by prophylactic calcitriol soaking.


2011 ◽  
Vol 6 (5) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Jakub Chlebek ◽  
Kateřina Macáková ◽  
Lucie Cahlíková ◽  
Milan Kurfürst ◽  
Jiří Kuneš ◽  
...  

Tubers of Corydalis cava were extracted with ethanol and fractionated using n-hexane, chloroform and ethanol. Repeated column chromatography, preparative TLC and crystallization led to the isolation of fifteen isoquinoline alkaloids. The chemical structures of the isolated compounds were determined on the basis of spectroscopic techniques and by comparison with literature data. All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. (+)-Canadaline inhibited acetylcholinesterase as well as butyrylcholinesterase in a dose-dependent manner with IC50 values of 20.1 ± 1.1 μM and 85.2 ± 3.2 μM, respectively. (+)-Canadine, with an IC50 value of 12.4 ± 0.9 μM, was the most potent inhibitor of acetylcholinesterase, whilst (±)-corycavidine and (+)-bulbocapnine were effective inhibitors of butyrylcholinesterase with IC50 values of 46.2 ± 2.4 uM and 67.0 ± 2.1 μM, respectively. The other isolated alkaloids were considered inactive (IC50 > 100 μM).


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chunyan Hao ◽  
Zefeng Gao ◽  
XianJun Liu ◽  
Zhijiang Rong ◽  
Jingjing Jia ◽  
...  

AbstractPropionate has been reported to exert antidepressant effects, but high-dose propionate may induce autism-like symptoms in experimental animals through induction of dysbiosis of neurotransmitters. The bi-directional effects of propionate seem to be dose-dependent. However, due to the pathological discrepancies between depression and autism, conclusions drawn from autism may not be simply transferable to depression. The effect and underlying action mechanisms of high-dose propionate on depression remains undetermined. To investigate the effects of propionate on depression, propionate dose gradients were intravenously administrated to rats exposed to chronic unpredictable mild stress (CUMS) for 1 week. Results of these behavioral tests demonstrate that low-dose propionate (2 mg/kg body weight/day) induces antidepressant effect through bodyweight recovery, elevated reward-seeking behaviors, and reduced depression-like behaviors, while high-dose propionate (200 mg/kg body weight/day) induces prodepressant effects opposite of those of low-dose propionate. A comprehensive profiling of neurotransmitters in the hippocampus demonstrated that CUMS induces reduction of NE (Norepinephrine), DA (Dopamine). GABA (γ-aminobutyric acid) was recovered by low-dose propionate, while high-dose propionate exerted more complicated effects on neurotransmitters, including reduction of NE, DA, 5-Hydroxytryptamine and Tryptophan, and increase of GABA, Kynurenine, Homovanillic acid, 3-hydroxyanthranilic acid, 3-hydroxykynurenine, 3,4-dihydroxyphenylacetic acid, and 3-methoxytyramine. The neurotransmitters disturbed by high-dose propionate suggest metabolic disorders in the hippocampus, which were confirmed by the clear group separation in PCA of metabolomic profiling. The results of this study demonstrate the double-edged dose-dependent effects of propionate on depression and suggest potential cumulative toxicity of propionate as a food additive to mood disorders.


2008 ◽  
Vol 197 (2) ◽  
pp. 351-358 ◽  
Author(s):  
Masaki Kakeyama ◽  
Hideko Sone ◽  
Chiharu Tohyama

Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during the fetal and neonatal periods has been indicated to alter the development of the offspring later in life. In this study, we determined whether perinatal exposure to a low dose of TCDD affects the onset of puberty in the female offspring of Long-Evans hooded rats. On day 15 of gestation, pregnant female rats were administered TCDD by gavage at a single dose of 0 (vehicle), 200, or 800 ng/kg b.w. In the female offspring born to dams administered with TCDD at either 200 or 800 ng/kg b.w., the vaginal opening and first estrus occurred ∼4–7 days earlier than in the offspring born to vehicle-treated animals. The ovarian weight gain was also accelerated following exposure to TCDD in a dose-dependent manner. We next examined the ovarian compensatory hypertrophy (OCH) as an indicator of the maturation of the LH/GnRH-generating system in the pituitary and the hypothalamus. Exposure to TCDD accelerated the onset of OCH in the female offspring in a dose-dependent manner. In particular, in the offspring born to the dams exposed to TCDD at 800 ng/kg b.w., hypertrophy, which is characterized by hyperovulation and a marked increase in the weight of the remaining ovary after hemi-ovariectomy, was observed on postnatal days 27–30, which was 10 days earlier than in the offspring born to the vehicle-treated dams. These results indicate that perinatal exposure to a low dose of TCDD induces precocious puberty, including early maturation of the hypothalamic–pituitary axis, the gonads and genitals, in female Long-Evans hooded rats.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Liqing Zhang ◽  
Haifeng Ni ◽  
Zhen Zhou ◽  
Xiaoyang Yuan ◽  
Junbo Xia ◽  
...  

Background. Maternal supplementation with 1α,25-dihydroxyvitamin D3 (VD3) has immunologic effects on the developing fetus through multiple pathways. This study was aimed at investigating the effects of VD3 supplementation on immune dysregulation in the offspring during allergic rhinitis. Methods. Different doses of VD3 as well as control were given to pregnant female mice. Ovalbumin (OVA) challenge and aluminum hydroxide gel in sterile saline were used to induce allergic rhinitis in offspring mice. Nasal lavage fluids (NLF) were collected, and eosinophils were counted in NLF 24 hours after the OVA challenge. Th1, Th2, Th17, and Treg subtype-relevant cytokines, including IFN-γ, IL-4, IL-10, IL-17, TGF-β, and OVA-IgE levels from the blood and NLF of offspring mice, were detected by the enzyme-linked immunosorbent assay (ELISA) method. The Treg subtype was analyzed by flow cytometry. Treg cells were purified from offspring and were adoptively transferred to OVA-sensitized allogenic offspring mice. The outcomes were assessed in allogenic offspring. Results. Our data showed that VD3 supplementation significantly decreased the number of eosinophils, basophils, and lymphocytes in the peripheral blood and NLF. The proportion of CD4+CD25+FoxP3+Tregs had a positive correlation with VD3 in a dose-dependent manner. The levels of serum IgE, IL-4, and IL-17 were decreased while the expressions of IFN-γ, IL-10, and TGF-β were significantly enhanced in VD3 supplementation groups. Adoptive transfer CD4+CD25+FoxP3+Tregs of VD3 supplementation groups promoted Th1 and suppressed Th2 responses in the offspring during allergic rhinitis. Conclusion. Our findings indicated that low dose VD3 supply in pregnant mice’s diet suppressed Th2 and Th17 responses in allergic rhinitis by elevating the Th1 subtype and the proportion of CD4+CD25+FoxP3+Tregs in offspring. It suggested that low dose VD3 supply may have the potential to act as a new therapeutic strategy for allergic rhinitis.


Insects ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
Steven C. Cook

Use of neonicotinoid pesticides is now ubiquitous, and consequently non-targeted arthropods are exposed to their residues at sub-lethal doses. Exposure to these neurotoxins may be a major contributor to poor honey bee colony health. Few studies have explored how sub lethal exposure to neonicotinoids affects honey bee metabolic physiology, including nutritional and energetic homeostasis, both of which are important for maintaining colony health. Reported here are results from a study of chronic oral exposure of honey bees to two sub lethal concentrations of clothianidin and imidacloprid. Neonicotinoids altered important aspects of honey bee nutritional and metabolic physiology in a compound and dose-dependent manner; both compounds at low doses reduced honey bee body weight. Low-dose clothianidin exposure resulted in bees having protein, lipids, carbohydrates, and glycogen levels similar to newly emerged bees. High-dose clothianidin exposure lowered lipids and glycogen content of bees. High-dose imidacloprid exposure resulted in bees having depressed metabolic rate. Low-dose imidacloprid exposure resulted in bees consuming low and high levels of protein and carbohydrate rich foods, respectively. Results suggest neonicotinoids interfere with honey bee endocrine neurophysiological pathways. Compound and dose-dependent effects might represent respective chemical structural differences determining an observed effect, and thresholds of compound effects on honey bee physiology.


Biomolecules ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 265 ◽  
Author(s):  
Jeong Ah Lee ◽  
Seok Joon Hwang ◽  
Sung Chan Hong ◽  
Cheol Hwan Myung ◽  
Ji Eun Lee ◽  
...  

Melanosomes undergo a complex maturation process and migrate into keratinocytes. Melanophilin (Mlph), a protein complex involving myosin Va (MyoVa) and Rab27a, enables the movement of melanosomes in melanocytes. In this study, we found six miRNAs targeting Mlph in mouse using two programs (http://targetscan.org and DianaTools). When melan-a melanocytes were treated with six synthesized microRNAs, miR-342-5p, miR-1839-5p, and miR-3082-5p inhibited melanosome transport and induced melanosome aggregation around the nucleus. The other microRNAs, miR-5110, miR-3090-3p, and miR-186-5p, did not inhibit melanosome transport. Further, miR-342-5p, miR-1839-5p, and miR-3082-5p decreased Mlph expression. The effect of miR-342-5p was the strongest among the six synthesized miRNAs. It inhibited melanosome transport in melan-a melanocytes and reduced Mlph expression in mRNA and protein levels in a dose-dependent manner; however, it did not affect Rab27a and MyoVa expressions, which are associated with melanosome transport. To examine miR-342-5p specificity, we performed luciferase assays in a mouse melanocyte-transfected reporter vector including Mlph at the 3′-UTR (untranslated region). When treated with miR-342-5p, luciferase activity that had been reduced by approximately 50% was restored after inhibitor treatment. Therefore, we identified a novel miRNA affecting Mlph and melanosome transport, and these results can be used for understanding Mlph expression and skin pigmentation regulation.


1992 ◽  
Vol 263 (3) ◽  
pp. R572-R577 ◽  
Author(s):  
N. Calingasan ◽  
S. Ritter ◽  
R. Ritter ◽  
L. Brenner

Exogenous cholecystokinin (CCK) suppresses food intake by acting on vagal sensory neurons. However, CCK doses used in behavioral experiments are generally much larger than those necessary to produce electrophysiological changes in vagal afferents. We made automated measurements of liquid food intake before, during, and after infusion of low doses of CCK octapeptide (CCK-8) through a chronic aortic catheter with its tip seated just above the celiac juncture. In parallel experiments, we made similar infusions while collecting blood from the hepatic portal and jugular veins for CCK assay. Injection of 10, 30, 50, and 70 pmol of CCK-8 suppressed feeding in a dose-dependent manner beginning 1 min postinfusion. The lowest dose to produce statistically significant suppression of preinfusion intake was 30 pmol. Infusion of the same CCK-8 doses into the jugular vein did not suppress feeding. Near-celiac injection of 30 pmol of CCK-8 produced systemic plasma CCK concentrations averaging 6.5 +/- 1 pM compared with less than 1 pM after saline injection. These findings show that exogenous CCK, by acting on tissues perfused by the celiac artery, can suppress feeding at doses that 1) are similar to those producing effects on the firing of vagal neurons and 2) do not increase plasma CCK concentrations above postprandial levels.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 999-999
Author(s):  
Denise E. Sabatino ◽  
Amy M. Lange ◽  
Melinda Mucci ◽  
Rita Sarkar ◽  
Aaron M. Dillow ◽  
...  

Abstract Hemophilia A (HA) is an X-linked bleeding disorder characterized by deficiency in clotting factor VIII (FVIII). Current treatment for hemophilia is protein replacement therapy while a gene-based therapy would provide continuous expression of even low levels of FVIII protein (>1% of normal) that is likely to improve the disease phenotype. It is challenging to utilize an AAV-mediated gene transfer approach for the FVIII cDNA (4.4kb) since the AAV vector can only efficiently accommodate a <5.3kb transgene cassette. The FVIII protein is composed of 2 chains -the heavy chain (HC) and the light chain (LC). FVIII undergoes proteolytic cleavage and processing of the 2 individual chains that form the active FVIII protein. In other studies in HA dogs (n=8), no dose-response and AAV serotype-dependent FVIII expression has been documented, which illustrates the difficulties in using a FVIII single-chain approach. We have utilized a 2-chain approach in which the 2.4kb LC cDNA is packaged in one AAV vector while the 2.5kb HC is packaged into a second AAV vector. Each construct contains a 695bp thyroxine-binding globulin gene promoter/enhancer fused to a 175bp intron along with a 263bp SV40 poly A signal. For this approach the LC and HC vectors packaged into either AAV8 or AAV9 were administered to HA dogs via the hepatic artery. Two male HA dogs received HC and LC in AAV8 and 2 male dogs received HC and LC in AAV9 at doses of 6x1012gc/vector/kg (low dose) or 1.25x1013gc/v/kg (high dose). At 150 days after vector infusion, the high dose group expressed FVIII at levels of 4.8% (AAV8) and 3% (AAV9) as detected by a functional assay (Coatest assay). FVIII remained stable for 797 days (AAV8) and >200 days (AAV9) (the longest time points to date) without any evidence of antibody formation to the transgene. In the low dose group at 150 days, FVIII levels were 1.5% (AAV8) and 0.5% (AAV9) cFVIII activity and were maintained in a follow up period of >150 days (AAV8) and >700 days (AAV9) without formation of antibodies to FVIII. Thus, no major differences between AAV8 and AAV9 vectors were observed. The transgene product is also functional based on shortening of whole blood clotting time (baseline values >50 min), in a dose-dependent manner, 10–15 min and 16–20 min for the high and low dose cohorts, respectively. Interestingly, high dose injection of AAV8 to 2 female HA dogs (1.25x1013 and 3x1013gc/v/kg) results in FVIII levels of 1–2%, which is consistent with data obtained in mice on the poor performance of AAV in mediating gene transfer to liver in female animals. Liver function tests and other blood chemistries were transiently elevated after the surgical procedure and were in normal limits within 4 days. Importantly, all dogs did not develop antibodies to FVIII. These findings suggest that FVIII chains efficiently assemble in vivo without increasing the protein immunogenicity. The 4 male dogs have remained asymptomatic with no spontaneous bleeds, whereas >20 bleeding episodes were expected for this group since untreated dogs require 5.5 plasma infusions/year. These data demonstrate for the first time, dose-dependent sustained expression of functional cFVIII in HA dogs by AAV8 and AAV9 vectors without formation of antibodies to cFVIII.


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