Administration Of CB Research Articles

Probiotic Clostridium butyricum ameliorated motor deficits in a mouse model of Parkinson’s disease via gut microbiota-GLP-1 pathway

A connection between gut microbiota and Parkinson’s disease (PD) indicates that dysbiosis of the gut microbiota might represent a risk factor for PD. Microbiota-targeted interventions, including probiotic Clostridium butyricum (Cb), have been recently shown to have favorable effects in PD by regulating microbiota-gut-brain axis. However, the potential beneficial roles and its mechanisms of Cb on PD were still unknown. Male C57BL/6 mice were subjected to a PD model-induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) and were treated intragastrically with Cb for 4 weeks. The motor functions were assessed by a series of behavioral tests including pole test, beam walking teat, forced swimming test and open field test. The dopaminergic neuron loss, synaptic plasticity and microglia activation, as well as the levels of colonic glucagon-like peptide-1 (GLP-1), colonic G protein-coupled receptors GPR41/43 and cerebral GLP-1 receptors were assessed. Gut microbial composition was assessed by 16S rRNA sequencing analysis. Our results showed that oral administration of Cb could improve motor deficits, dopaminergic neuron loss, synaptic dysfunction and microglia activation in the MPTP-induced mice. Meanwhile, Cb treatment could reverse the dysbiosis of gut microbiota and the decreased levels of colonic GLP-1, colonic GPR41/43 and cerebral GLP-1 receptor in the MPTP-induced mice. These findings indicated that the neuroprotective mechanism of Cb on PD might be related to the improvement of abnormal gut microbiota-gut-brain axis.

Abstract 4927: Silencing of the RAD50 gene contributes to enhancing the sensitivity of the triple-negative breast cancer cells to carboplatin

Abstract Triple-negative (TN) breast cancer (BC) is the most aggressive molecular subtype of BC that affected over 250 thousand females worldwide just in 2018. Patients with TNBC have exhibited a higher probability of cancer relapses and poor prognosis of disease outcome which are due to the absence of established and reliable targets for therapy of this subtype of tumors. Only 10% of TN breast tumors have BRCA1/2 mutations associated with high sensitivity of cancer cells to the chemotherapy with platinum salts drugs (e.g., cisplatin, carboplatin (Cb), etc.) and PARP-inhibitors. Recent studies indicated that administration of Cb in neoadjuvant chemotherapy of TNBC increase pCR (pathologic complete response) of patients received Cb in comparison with a control group. Also, Phase II and III of clinical trials have shown that TNBC patients respond differently to adjuvant chemotherapy with Cb. Therefore further studies are required to define subgroups of TNBC patients, which might benefit from carboplatin therapy. In our previous studies, the RAD50 gene involved in radiation-induced DNA double-strand break repair was identified as a tumor-associated antigen and potential BC marker. We have shown that low expression of RAD50 gene is associated with better TNBC prognosis. The current study was aimed to evaluate RAD50 as a predictive marker of TNBC cells sensitivity to Cb. The RAD50 gene was silenced in triple negative breast cancer cell lines with wild-type BRCA genes namely MDA-MB-231, MDA-MB-436, and MDA-MB-453 by RNA interference. Then the changes of the cytotoxic sensitivity of these cells to Cb treatment in comparison to the control cells with original RAD50 expression were investigated by using a cell viability assay. Obtained data were analyzed by the Wilcoxon signed-rank test. The statistical analysis was performed using GraphPad Prism 7 software. Results of this study demonstrated that the knockdown of RAD50 gene expression in human TNBC cells could significantly increase their susceptibility to treatment with Cb (MDA-MB-231: IC50 - 20,65uM (silenced RAD50) and 24,93uM (control), p-value = 0,0098; MDA-MB-436: IC50 - 7,497uM (silenced RAD50) and 10,39uM (control), p-value = 0,0137; MDA-MB-453: IC50 - 7,336uM (silenced RAD50) and 8,711uM (control), p-value = 0,002). These results strongly indicate that silencing of the RAD50 expression contributes to the sensitization of TNBC cells to treatment with platinum-based drug Cb. Therefore RAD50 could be considered as important TNBC predictive biomarker. Further validation of RAD50 by using the tumors of TNBC patients and animal xenograft models could prove to be essential to use this marker for improving the therapy regimens of TNBC tumors without BRCA1/2 mutations. This work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University. Citation Format: Kristina V. Havrysh, Mikhail V. Bogdanov, Ramziya G. Kiyamova. Silencing of the RAD50 gene contributes to enhancing the sensitivity of the triple-negative breast cancer cells to carboplatin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4927.

A Synthetic Receptor as a Specific Antidote for Paraquat Poisoning.

Accidental or suicidal ingestion of the world's most widely used herbicide, paraquat (PQ), may result in rapid multi-organ failure with a 60% fatality rate due to the absence of an effective detoxification solution. Effective, specific antidotes to PQ poisoning have been highly desired.Methods: The binding constant of PQ and a synthetic receptor, cucurbit[7]uril (CB[7]), was first determined in various pH environments. The antidotal effects of CB[7] on PQ toxicity were firstly evaluated with in-vitro cell lines. With in-vivo mice models, the pharmacokinetics and the biodistribution of PQ in major organs were determined to evaluate the influence of CB[7] on the oral bioavailability of PQ. Major organs' injuries and overall survival rates of the mice were systemically examined to evaluate the therapeutic efficacy of CB[7] on PQ poisoning.Results: We demonstrate that CB[7] may complex PQ strongly under various conditions and significantly reduce its toxicity in vitro and in vivo. Oral administration of PQ in the presence of CB[7] in a mouse model significantly decreased PQ levels in the plasma and major organs and alleviated major organs' injuries, when compared to those of mice administered with PQ alone. Further studies indicated that oral administration of CB[7] within 2 h post PQ ingestion significantly increased the survival rates and extended the survival time of the mice, in contrast to the ineffective treatment by activated charcoal, which is commonly recommended for PQ decontamination.Conclusion: CB[7] may be used as a specific oral antidote for PQ poisoning by strongly binding with PQ and inhibiting its absorption in the gastrointestinal tracts.

Anti-inflammatory and antioxidant effect of Kerabala: a value-added ayurvedic formulation from virgin coconut oil inhibits pathogenesis in adjuvant-induced arthritis.

Kerabala (CB) is a novel ayurvedic formulation used for treating various inflammatory diseases. This formulation was made from virgin coconut oil and it comprises extracts of Sida cordifolia, coconut milk and sesame oil. The current study was performed to evaluate the anti-inflammatory action of CB on carrageenan-induced acute and adjuvant-induced chronic experimental models. 5mg/kg bwt was found to be potent dose from carrageenan model and evaluated its effect in adjuvant-induced chronic arthritic model. The antioxidant assays like SOD, catalase, glutathione peroxidase, lipid peroxidation product, nitrate level and GSH were measured in paw tissue. Hematological parameters like hemoglobin (HB) count, ESR, WBC count, plasma CRP levels were analyzed. By RT-PCR, the inflammatory markers like cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) expressions were evaluated. The extracellular matrix proteins like MMP-2 and MMP-9 were determined by zymography and its expression by western blotting. Histopathology and cytology of paw tissue and synovium were analyzed. The result indicated that there was a significant increment in the levels of antioxidant enzymes on CB administration. The hematological markers such as ESR, WBC and plasma CRP levels were reduced by CB treatment and it also increases the HB level. The upregulated gene level expressions of inflammatory markers like COX-2, iNOS, TNF-α and IL-6 were down regulated by administration of CB. MMP-2 and MMP-9 expression significantly reduced by CB administration. Massive influx of inflammatory cell infiltration, proliferative collagen in histological analysis of paw tissue of arthritic rat was decreased by CB administration. Synovial cytology of CB administrated group shows reduced number of reactive mesothelial cells and synovial inflammatory cells. This current study shows that ayurvedic drug CB has an antioxidant, anti-inflammatory and anti-arthritic activity in experimental arthritic model. CB as an anti-arthritic drug has beneficial effect for treating inflammation, tissue damage and pain associated with arthritis.

Toxicity effect of sub-chronic oral administration of class bitters® - a polyherbal formula on serum electrolytes and hematological indices in male Wistar albino rats

The indiscriminate administration of ready-to-use herbal formulations has become a major concern due to their potential health risk. The study investigated the effect of class bitters® (CB) - a polyherbal formula prepared with Mondia whitei, Khaya senegalensis, Capparis erythrocarpus, Thoningia sanguinea and Xylopia aethiopica on serum electrolytes and hematological parameters in male Wistar albino rats. Two doses (500 and 1000 mg kg–1) of the polyherbal drugs were administered orally to male Wistar albino rats for a period of 9 weeks. The results showed that administration of 500 and 1000 mg kg–1 body weight of CB recorded a marked increase in the levels of sodium and chlorum when compared with control. However, there was a marked reduction in the levels of potassium and hydrogen carbonate. The results of the study also showed a significant (P≤0.05) decrease in the level of hematological parameters such as hemoglobin (Hb), packed cell volume (PCV), red blood cells (RBCs) and platelets levels in the male Wistar albino rats, when compared with control. The marked decrease in Hb, PCV, RBCs and platelets concentrations observed in experimental rats in this study suggest that CB may have an adverse effect on erythropoiesis. These observations therefore showed that long-term administration of CB might cause renal disease and anemia.

A comparative study on toxicity induced by carbosulfan and malathion in Wistar rat liver and spleen

Organophosphorus (OP) and carbamate (CM) pesticides are widely used in agriculture. These pesticides are highly toxic to humans and their residues in food pose potential threat to human health. In this comparative study, we investigated the effect of subchronic exposure of OPs (malathion, MAL) and CM (Carbosulfan, CB) on rat liver and spleen. Biochemical analysis showed that levels of hepatic enzymes (ALT, ALP, LDH and PAL) changed after exposure to the pesticides. In the liver extracts, lipid peroxidation index increased after the treatment by pesticides. Our results indicated that exposure to MAL and CB leads to alteration of liver redox status. Both pesticides induced focal inflammation and fibrosis in the liver. After subchronic administration of MAL (200 mg/kg) and CB (25 mg/kg), systemic inflammation, as depicted by the increase in IFN-δ activity in liver, was observed in both malathion and carbosulfan treated animals. In addition, the results showed that MAL significantly increased TCD4+ and TCD8+ lymphocyte number. It also decreased INF-δ and IL-4 production. However, CB induced a reduction of TCD8+ number and cytokine production in spleen cells. In conclusion, malathion and carbosulfan had significant immunomodulatory properties in the spleen with inflammation and oxidative stress induction in the liver.

Abstract 5728: The synergistic effect of Cucurbitacin B and radiation treatment

Abstract Cucurbitacin B (CB), a small molecule purified from Trichosanthes kirilowii Maximowicz, possesses a potent antitumor effect. In this study, we investigated the combined effect of CB and ionizing radiation (IR) on aggressive 4T1 breast cancer cells. In a clonogenic assay, different doses of CB (0, 1.7, or 5 nM) and IR (0, 2, 4, or 6 Gy) were applied to 4T1 cells either in a single regimen or in combination. The surviving fraction at 2 Gy was greatly reduced with the increased doses of CB. The results calculated with CompuSyn program indicated that the combination index (CI) was <1 and the dose reducing index (DRI) was >1, suggesting that the combination of CB and IR has a synergistic effect against cancer cells. Our studies of the underlying mechanism revealed that: 1) CB enhanced IR-induced loss of mitochondria potential, as evidenced by a 10-20% increase in the transition of aggregative JC-1 (representing healthy cells) into monomeric JC-1 (representing early apoptotic cells); 2) cell-cycle analysis revealed that although samples treated with CB or 3 Gy alone had 38% or 29% of cells, respectively, in the G2-M phase as compared to 23% of the vehicle control, the combined treatment encouraged 51% of cells to accumulate in the G2-M phase; and 3) the Western blot assay indicated that survival-related molecules (e.g., phosphorylated Stat 3, c-Myc, Bcl-2, and Bcl-xL) were downregulated, while apoptosis-related molecules (e.g., caspase-9, p21, and p53) were upregulated in the combined treatment group. The data reveal that the systemic administration of CB will not only stop the spread of micrometastases but also enhance local tumor control, which will result in better treatment outcomes. The clinical value of CB should be further explored. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5728. doi:1538-7445.AM2012-5728

CB 1 receptors modulate the intake of a sweetened-fat diet in response to mu-opioid receptor stimulation of the nucleus accumbens

Previous research has demonstrated that concurrent systemic administration of CB 1 cannabinoid and mu-opioid receptor agonists increases feeding in rats. However, the possible neural loci of this cooperative effect have yet to be identified. These studies tested whether the nucleus accumbens shell may be one site of the interactive effects of opioid and cannabinoid ligands on feeding. Injection of the mu-opioid agonist DAMGO (at 0, 0.025, 0.25, or 2.5 µg/0.5 µl/side) directly into the rat nucleus accumbens shell increased feeding on a sweetened-fat diet, and this effect was blocked by pretreatment with either the mu-opioid antagonist naltrexone (20 µg/0.5 µl/side) or the CB 1 antagonist SR141716 (0.5 µg/0.5 µl/side). Activation of nucleus accumbens shell CB 1 receptors with WIN55212-2 alone (at 0.1 or 0.5 µg/0.5 µl/side) had no apparent effect on food intake. However, local injections of the low dose of DAMGO (.025 µg/0.5 µl/side) in this region along with WIN55212-2 (at 0.25 or 0.50 µg/0.5 µl/side) increased feeding above that induced by DAMGO alone. These data suggest an important modulatory role for cannabinoid receptors in the expression of feeding behaviors in response to mu-opioid receptor activation of the nucleus accumbens shell.

Toxicity of cucurbit[7]uril and cucurbit[8]uril: an exploratory in vitro and in vivo study

Cucurbit[n]urils (CB[n]) are potential stabilizing, solubilizing, activating, and delivering agents for drugs. The toxicity of the macrocyclic host molecules cucurbit[7]uril (CB[7]), the most water-soluble homologue, as well as cucurbit[8]uril (CB[8]) has been evaluated. In vitro studies on cell cultures revealed an IC(50) value of 0.53 +/- 0.02 mM for CB[7], corresponding to around 620 mg of CB[7] per kg of cell material. Live-cell imaging studies performed on cells treated with subtoxic amounts of CB[7] showed no detrimental effects on the cellular integrity as assessed by mitochondrial activity. For CB[8], no significant cytotoxicity was observed within its solubility range. The bioadaptability of the compounds was further examined through in vivo studies on mice, where intravenous administration of CB[7] showed a maximum tolerated dosage of 250 mg kg(-1), while oral administration of a CB[7]/CB[8] mixture showed a tolerance of up to 600 mg kg(-1). The combined results indicate a sufficiently low toxicity to encourage further exploration of CB[n] as additives for medicinal and pharmaceutical use.

Central Versus Peripheral Antagonism of Cannabinoid CB1 Receptor in Obesity: Effects of LH‐21, a Peripherally Acting Neutral Cannabinoid Receptor Antagonist, in Zucker Rats

The endogenous cannabinoid system plays an important modulatory role in feeding behaviour and metabolism, acting at both central and peripheral levels. Chronic administration of cannabinoid CB(1) receptor antagonists has been found to be effective in experimental obesity. However, clinically available cannabinoid receptor antagonists are inverse agonists that can target CB(1) receptors located in both central circuits regulating appetite and motivation and in peripheral organs regulating metabolism and energy expenditure. This profile complicates understanding of cannabinoid CB(1) receptor blockade as a therapeutic strategy in obesity and metabolic disorders. This review aims to explore the relevance of both inverse agonism and peripheral cannabinoid receptor blockade on the beneficial actions of chronic cannabinoid receptor blockade, by comparing the actions of the reference antagonist/inverse agonist rimonabant and the newly designed drug LH-21. LH-21 is a triazol derivative and a neutral cannabinoid receptor antagonist; it has a poor penetration rate into the central nervous system. When given acutely it decreases food intake and enhances the anorectic actions of oleoylethanolamide, a feeding suppressant lipid that acts on peripheral sensory terminals in a similar way as rimonabant. Unlike rimonabant, chronic administration of LH-21 (3 mg/kg) reduces feeding but does not improve hypertriglyceridaemia or hypercholesterolaemia; nor does it reduce liver fat deposits in Zucker rats. These results suggest that the inverse agonism and/or the antagonism of central cannabinoid CB(1) receptors are necessary for the metabolic benefits of cannabinoid CB(1) receptor blockade, but not for the appetite reduction.

Hepatic nitroreduction, toxicity and toxicokinetics of the anti-tumour prodrug CB 1954 in mouse and rat

5-(Aziridin-1-yl)-2,4-dinitrobenzamide (CB 1954), a promising anti-tumour compound, is associated with clinical hepatotoxicity. We have previously demonstrated that human liver preparations are capable of endogenous 2- and 4-nitroreduction of CB 1954 to generate highly potent cytotoxins. The present study initially examined the in vitro metabolism of CB 1954 in S9 preparations of several non-clinical species and strains. The CD-1 nu/ nu mouse and Sprague–Dawley rat were subsequently chosen for further assessment of in vivo metabolism and hepatotoxicity of CB 1954, as well as the mechanisms that may be involved. Animals were administered the maximum tolerated dose (MTD). At 562 μmol/kg, the mouse exhibited transaminase elevation and centrilobular hepatocyte injury. Moreover, thiol adducts as well as hepatic glutathione depletion paralleled temporally by maximal nitroreduction were observed. The rat had a much lower MTD of 40 μmol/kg and showed signs of gastro-intestinal disturbances. In contrast to mouse, peri-portal damage and biliary changes were observed in rat without any alterations in plasma biomarkers or hepatic glutathione levels. Immunohistochemical analysis did not reveal any correlation between the location of injury and expression of cytochrome P450 reductase and NAD(P)H quinone oxidoreductase 1, two enzymes implicated in the bioactivation of this drug. In conclusion, the present study showed that following administration of CB 1954 at the respective MTDs, hepatotoxicity was observed in both mouse and rat. However, the degree of sensitivity to the drug and the mechanisms of toxicity involved appear to be widely different between CD-1 nu/ nu mice and Sprague–Dawley rats.

The local antinociceptive effects of paracetamol in neuropathic pain are mediated by cannabinoid receptors

Paracetamol analgesic mechanism of action is still poorly defined but mainly involves central inhibition of cyclooxygenases. Here we tested the peripheral antinociceptive effects of paracetamol (intraplantar injections) in a rat model of neuropathic pain. Paracetamol dose-dependently decreased mechanical allodynia and lowered nociceptive scores associated with hyperalgesia testing. These effects were inhibited by the administration of cannabinoid CB(1) (AM251) and CB(2) (AM630) receptor antagonists. The participation of the peripheral cannabinoid system in paracetamol analgesia is suggested.

Androgen receptor and c-Myc transcription factors as putative partners in the in vivo cross-talk between androgen receptor-mediated and c-Met-mediated signalling pathways.

Cross-talk between two signal transduction pathways leads to a negative regulation of androgen-induced ornithine decarboxylase (ODC) gene expression in the mouse kidney. One pathway is triggered by testosterone via the intracellular androgen receptor, AR, and the other is induced by antifolate CB 3717 or folate via hepatocyte growth factor and its cell membrane receptor c-Met. Here we report the studies of the expression of AR and c-Myc transcription factors involved in ODC transactivation. Administration of CB 3717 or folate decreased the expression of AR. In contrast, testosterone did not modify AR mRNA content but augmented the AR protein. Furthermore, we demonstrate that administration of folate, but not testosterone, increases c-Myc transcript and protein level. We also document that activation of both examined pathways does not decrease the testosterone-induced AR protein level, but markedly increases c-Myc protein which is nearly 2-fold up-regulated compared to its level evoked solely by testosterone. We suspect that this pronounced increase of c-Myc protein might have functional consequences mirrored by down-regulated expression of AR target genes, among them ODC.

Involvement of cannabinoid CB 2 receptors in the IgE-mediated triphasic cutaneous reaction in mice

Involvement of cannabinoid CB 2 receptors in the IgE-mediated cutaneous reaction was investigated. Epicutaneous challenge with 2,4-dinitrofluorobenzene caused a triphasic swelling in the ear of BALB/c and C57BL/6 mice passively sensitized with anti-dinitrophenol IgE. Peak responses of the ear swelling appeared at 1 h, 24 h, and 8 days after the challenge in both strains of mice. In contrast, cannabinoid CB 2 receptor-deficient mice failed to exhibit the obvious triphasic ear swelling observed in wild-type mice. Oral administration of cannabinoid CB 2 receptor antagonist/inverse agonists [ N-(benzo[1,3]dioxol-5-ylmethyl)-7-methoxy-2-oxo-8-pentyloxy-1,2-dihydroquinoline-3-carboxamide] (JTE-907) and { N-[(1S)- endo-1,3,3-trimethylbicyclo[2,2,1]heptan-2yl]5-(4-chloro-3-methyl-phenyl)-1-(4-methylbenzyl)pyrazole-3-carboxamide} (SR144528) at doses of 0.1–10 mg/kg significantly and dose-dependently suppressed all three phases of ear swelling in BALB/c mice. Interestingly, epicutaneous treatment with an ether-linked analogue of endogenous cannabinoids, 2-arachidonoylglycerol, caused an ear swelling that could be detected at 1 h, 24 h, and 8 days after treatment of both BALB/c and C57BL/6 mice. These results suggest that cannabinoid CB 2 receptors are involved in induction of the triphasic cutaneous reaction mediated by IgE, and that cannabinoid CB 2 receptor antagonist/inverse agonists may serve as anti-allergic agents in the treatment of allergic dermatitis.

Effects of Δ 9-THC on VIP-induced prolactin secretion in anterior pituitary cultures: evidence for the presence of functional cannabinoid CB 1 receptors in pituitary cells

Peripheral administration of cannabinoid CB 1 receptor agonists to laboratory rats induce a brief rise in plasma prolactin (PRL) levels followed by a prolonged decrease in PRL secretion from the pituitary. While the inhibitory component of this biphasic response depends on the cannabinoid-induced activation of dopamine release from hypothalamic terminals located in the median eminence, the neurobiological mechanisms underlying the activation phase of PRL release remains to be explained. In the present study the possible direct effect of the cannabinoid receptor agonist Δ 9-Tetrahydrocannabinol (THC) on prolactin secretion and cAMP accumulation was examined in anterior pituitary cultures. THC (0.1 and 1 μM) increased cAMP levels, and induced PRL release (1 and 10 μ). THC did not affect vasoactive intestinal peptide (VIP, 0.5 μM) induced cAMP accumulation in pituitary cultures, showing additive effects at THC 1 μM concentration. However, THC did prevent VIP-dependent increases in prolactin secretion. These results indicate that THC, through a direct pituitary action, activates both the synthesis of cAMP and PRL release and interferes with intracellular mechanisms involved in PRL secretion by VIP. These actions could be mediated through cannabinoid CB 1 receptors which were found to be present in anterior pituitary cells, including lactotrophs, as revealed by immunocytochemistry with a specific polyclonal antibody raised against the CB 1 receptor protein.

Norepinephrine Content in the Paraventicular Nucleus of the Hypothalamus as a Function of Photoperiod and Dopaminergic Tone

The decline in the release of various anterior pituitary hormones, particularly prolactin (PRL), as a result of exposure to inhibitory, short-day photoperiods in long-day breeders is a well-documented phenomenon. This alteration in the hypothalamic-hypophyseal-gonadal axis is largely controlled by changes in the duration of the nocturnal melatonin pulse secreted by the pineal gland. Increased duration of melatonin secretion serves to increase the inhibitory activity of the tuberoinfundibular dopaminergic (TIDA) neurons, which in turn suppress PRL release and synthesis. However, other hypothalamic factors also appear to stimulate anterior pituitary function, working in concert with changes in TIDA activity to modulate circulating PRL levels under different photoperiod conditions. Past work from this laboratory has suggested that neurochemical changes at the level of the hypothalamic paraventricular nuclei (PVN), particularly changes in norepinephrine (NE) activity, may represent one of these modulatory influences. The current study investigated potential alterations in NF, content within the PVN during the early stages of short-day exposure in Siberian hamsters. In addition, the interaction of NE content with the modulatory dopamine (DA) system was investigated via administration of a DA agonist (CD154) or antagonist (pimozide). Hamsters received CB 154 (500 micrograms), pimozide (45 micrograms), or control solution via the drinking water under either long days (16L:8D) or short days (10L:14D), and were sacrificed at 1, 3, or 5 wk of photoperiod and drug treatment. The brains were removed, and the PVN microdissected from the hypothalamus and analyzed for catecholamine content using high-pressure liquid chromatography with electrochemical detection (HPLC-EC). The results revealed the expected stimulation of circulating PRL under both photoperiods following pimozide administration, as well as the expected trend toward an accelerated suppression of PRL under short days induced by CB 154. For control animals, there were no changes in NE content, or the ratio of 3-methoxy-4-hydroxyphenyglycol (MHPG)/ NE in long-day exposed animalx, but for short-day animals, both NE content and the ratio of MHPG/NE declined over time. Administration of CB 154 had only a marginal effect on NE content and the ratio of MHPG/ NE, but pimozide administration resulted in a decline in NE content and an increase in the MHPG/NE ratio under short days, and an increase in NE content and the MHPG/NE ratio over time for long-day animals. These results suggest that both photoperiod and administration of a DA antagonist that increases circulating PRL levels induce alterations in NE terminal activity within the hypothalamic PVN.

Arginine and ornithine metabolizing enzymes in testosterone-induced hypertrophic mouse kidney

Administration of testosterone to female mice causes hypertrophy of their kidneys with spectacular induction of ornithine decarboxylase and significant increase in the level of putrescine. We tried to find out whether testosterone treatment affects also the renal activities of enzymes participating in the formation and utilization of ornithine, specifically arginase and ornithine aminotransferase, and whether they are dependent on putrescine level. Swiss, CFW, DBA2 or F1 (CFW × DBA2) female and male mice were injected with testosterone (125 mg/kg) or CB 3717 (100 mg/kg). DFMO was applied in the drinking water. The activities of the enzymes were determined 24 hr or 5 days after administration of CB 3717 or testosterone, respectively. Renal activities of ornithine decarboxylase (ODC), arginase and ornithine aminotransferase (OAT) were found to be sex-differentiated. The highest activity of ODC was characteristic for the kidneys of males, whereas those of arginase and OAT for the kidneys of females. In the kidneys of testosterone-treated female mice a decrease (50%) of OAT, and a significant increase of arginase activities (up to 200%), were observed. In the males these changes were less pronounced. DFMO, which completely inhibited the activity of renal ODC, did not influence significantly the testosterone-induced arginase and the testosterone-decreased OAT. Arginase and OAT, in contrast to ODC, were not changed in CB 3717-induced hyperplastic kidney. The study showed testosterone-induced differential changes in the activity of two enzymes involved in ornithine biosynthesis and catabolism which accompanied ODC induction in female mouse kidney. However ODC induction was not a prerequisite for these enzymatic changes as they did not follow ODC activation by CB 3717, and were not affected by DFMO, a specific inhibitor of ODC.

The foetoplacental unit and the initiation of lactation in the rat.

Rats were either Caesarean-sectioned, ovariohysterectomized or ovariectomized on day 19 of gestation and the role of prolactin and corticosteroids in the initiation of lactation was studied by administering 2-bromo-alpha-ergocryptine (CB 154) and prolactin, and by using adrenalectomy and foetectomy. The concentrations of corticosteroids and prolactin in the plasma and the weight and lactose content of the inguinal mammary glands were determined 48 h after Caesarean section, and 24 h after ovariohysterectomy and ovariectomy. The ranges in concentrations of corticosteroids, prolactin and mammary lactose were 207-348 micrograms/l plasma, 21.9-65.3 micrograms/l plasma and 1.21-4.50 mg/g tissue, respectively, the Caesarean-sectioned, ovariohysterectomized and ovariectomized rats. The administration of CB 154 after either Caesarean section, ovariohysterectomy or ovariectomy decreased the concentration of prolactin to less than 8.8 micrograms/l. Whereas CB 154 significantly depressed the lactose content of the mammary tissue in Caesarean-sectioned and ovariohysterectomized rats (0.42 and 0.31 mg/g tissue, respectively), no effect was observed in ovariectomized rats (1.39 mg/g tissue). The administration of ovine prolactin reversed the inhibitory effects of CB 154. Furthermore, in two rats which were not ovariectomized and foetectomized, CB 154 did not inhibit lactose accumulation in the mammary tissue (2.02 mg/g tissue). Adrenalectomy of ovariohysterectomized rats decreased corticosteroid concentrations from 348 to 14 microgram/l plasma and the lactose content of mammary tissue from 1.31 to 0.19 mg/g tissue. Whereas adrenalectomy of ovariectomized rats decreased corticosteroid concentrations to 53 micrograms/l, the lactose content of mammary tissue (1.82 mg/g tissue) remained within the range for ovariohysterectomized rats. These finding show that hormones produced in late pregnancy by the foetus and placenta can support lactogenesis in the rat in the absence of maternal prolactin and corticosteroids.

Naloxone potentiation of 2-Br-α-ergocryptine (CB 154) effects on GH secretion in man

The effect of the combined administration of either CB 154 (2.5 mg/osM) or L-DOPA (500 mg/osM) and naloxone have been studied in six normal male volunteers. Naloxone cause a clear-cut potentiation of CB 154 effects on human growth hormone (hGH) secretion and only a slight, statistically non-significant, potentiation of L-DOPA effects on hGH secretion. These results have been discussed in the light of morphofunctional findings showing possible interactions between dopamine (DA) systems and somatostatin-positive and enkephalin-positive nerve terminals.

Altered growth hormone and prolactin responses to dopaminergic stimulation in Huntington's chorea.

Seven patients affected by Huntington's chorea were given an acute administration of 2-Br-alpha-ergocryptine (CB 154, Sandoz), a direct agonist at dopamine receptor sites. Seven nonobese hospitalized patients were used as controls. Oral administration of CB 154 (2.5 mg) induced a more prompt and consistent rise in plasma growth hormone (GH) levels in patients than in controls. GH levels rose from baseline values of 0.3+/-0.1 ng/ml to mean peak values of 20.4+/-5.1 ng/ml (120-270 min) in choreic subjects and from baseline values of 1.0+/-0.4 ng/ml to mean peak values of 5.7+/-1.6 ng/ml (180-300 min) in control subjects (P less than 0.02). Baseline plasma prolactin (PRL) values were significantly higher in choreic than in control subjects (22.1+/-6.6 ng/ml vs. 8.1+/-1.4 ng/ml, respectively, P less than 0.02); administration of CB 154 induced a more consistent PRL decrease in control than in choreic subjects. Collectively, these results suggest the existence of an abnormal regulation of GH and PRL secretion in Huntington's chorea, probably due to alterations in central dopaminergic neurotransmission.