/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ eighteen female sheep received amounts of roquefortine equivalent to concentrations of zero, 5 and 25 mg/kg silage over a period of 16 to 18 days. During the experimental period no clinical signs of an intoxication could be recognized, Neither clinoco-chemical (ALT, AST, GLDH, bilirubin, blood glucose) nor hematological parameters (numbers of erythrocytes, leucocytes and thrombocytes; hemoglobin, packed cell volume) were changed by roquefortine. The profiles of LH, FSH and progesterone during the experimental period were similar to those of the control period. Only the pH of the rumen fluid decreased significantly (up to 0.5 units).
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Studies were undertaken to prescreen these hazardous chemicals for developmental toxicity utilizing a fresh water coelenterate, Hydra attenuata (HA). The assay was performed in a series of three phases. Phase I consisted of exposing only the adult hydra to whole-log concentrations of the individual toxins. The minimal affective concentrations (MACs) of the toxins were determined in the adult hydra and regenerating artificial hydra embryos (AHE) by bracketing the toxic endpoint to the nearest tenth (1/10) of a log in Phase II. The results (from Phase II) were confirmed in Phase III. Findings from the HA assay indicated that the MACs of MPA, ROQ, PA and PAT which resulted in toxic endpoints were equal to: 40.0, 30.0, 0.7 and 15.0 mg/L (in the adult hydra) and 30.0, 20.0, 0.7 and 15.0 mg/L (in the AHE), respectively. PAT produced the highest toxicity in the hydra. The A/D ratios (developmental hazard indices) of the toxins were in the range of 1.0 to 1.5, suggesting that these chemicals are co-effective developmental toxins.
/ALTERNATIVE IN VITRO TESTS/ Roquefortine interaction with rat and human liver cytochromes P450 was monitored by difference UV-vis spectroscopy. It was found to interact with different forms of the cytochromes, giving rise to a type II difference spectrum, characteristic of the binding of an amino function to the heme iron. Roquefortine exhibited high affinity for microsomes from rats treated with various inducers, the K(s) values being in the range 0.2-8 microM. Similar results were observed with human P450 enzymes 1A1, 1A2, 2D6, and 3A4. Roquefortine had no effect on NAPDH cytochrome c reductase. Therefore, inhibition of NADPH consumption was observed using various rat liver microsomes alone or in the presence of 100 microM testosterone in the case of dexamethasone (DEX)-rat microsomes. Enzymatic inhibition was studied in terms of P450 3A activities, i.e., testosterone 6beta-hydroxylase (IC(50) around 10 microM) or bromocriptine metabolism (IC(50) > 50 microM) using DEX-rat liver microsomes or P450 3A4, benzphetamine N-demethylase using phenobarbital-rat liver microsomes (IC(50) > 30 microM), and ethoxyresorufin metabolism using 3-methylcholanthrene-rat liver microsomes (IC(50) 0.1 microM), P450 1A1, and 1A2. Roquefortine was compared with compounds of similar structure: cyclo(Phe-His), cyclo(Phe-dehydroHis), cyclo(Trp-His), phenylahistin. These studies indicate that the =N- imidazole moiety coordinates with the heme iron, and suggest that the dehydroHis moiety and the presence of a fused tetracycle play an important part in roquefortine inhibitory power.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
非人类毒性摘录
/其他毒性信息/ 据报告,它能够产生神经毒性效应并抑制革兰氏阳性细菌的生长。
/OTHER TOXICITY INFORMATION/ It has been reported to cause neurotoxic effect and to inhibit Gram-positive bacteria growth.
Residues of roquefortine could be analysed in rumen fluid, feces, liver, bile, kidneys, and muscle /eighteen female sheep received amounts of roquefortine equivalent to concentrations of zero, 5 and 25 mg/kg silage over a period of 16 to 18 days/.