Comparative biochemistry and physiology. C: Comparative pharmacology最新文献

1. The optical isomers of 2-methoxy-5-phenyl-l,3,2-oxazaphospholidine 2-sulfide (5-PMOS) were synthesized by a chiral two-step phosphorylating method, and their absolute configurations and optical purities were determined by ¹H-NMR.

2. (S)c(R)p-trans-5-PMOS showed the highest activity and the activity decreased in the order of (S)c(R)p-trans->(R)c(R)p-cis->(R)c(S)p-trans->(S)c(S)p-cis-5-PMOS in reducing larval growth and inhibiting acetylcholinesterase (AChE) of the red flour beetle Tribolium castaneum Herbst.

3. (R)c(R)p-cis-5-PMOS showed the highest anti-AChE activity followed by (R)c(S)p-trans- >(S)c(R)p-trans->(S)c(S)p-cis-5-PMOS, corresponding with insecticidal activity against Musca domestica L.

4. Optical isomers of 5-PMOS were not effective in stimulating adenylate cyclase prepared from ventral nerve cords of Periplaneta americana L.

5. The reversed stereospecificity between the T. castaneum larval growth-inhibitory and M. domestica insecticidal activities of 5-PMOS optical isomers is due to a stereospecific difference in the intrinsic potency of active form of 5-PMOS isomers as AChE inhibitors with the two insects.

1. The premise of this review is that many of the biological effects of Pb are reflections of tissue peroxidation.

2. Enhanced tissue levels of arachidonic acid in Pb toxicosis appear to be involved in the peroxidative changes.

3. The altered arachidonate metabolism may be related to changes in membrane structure and function.

4. The induction of enhanced glutathione levels in animal tissues by Pb may afford protection from peroxidative damage.

1. Crayfish were exposed to $\text{1}\text{25}$ th 96-hr lc₅₀ and 96-hr lc₅₀ of lindane and endosulfan for 1, 24, 48, 72 and 96 hr.

2. Concentrations of lindane and endosulfan were determined in gill tissue at 22°C and 29°C.

3. Clear differences were found in all concentrations, times and temperatures tested in gill tissues.

4. The highest accumulation of pesticide was found in the lc₅₀ endosulfan value.

1. The acute combined effects of cadmium (Cd) and nickel (Ni) on rat hepatic glutathione S-transferase (GST) activities toward the substrates 1-chloro-2,4-dinitrobenzene (CDNB), l,2-dichloro-4nitrobenzene (DCNB) and ethacrynic acid (EAA) were determined and compared to those of Cd or Ni alone.

2. Male adult rats (225–275 g) were administered either a single dose of Cd (3.58 mg CdCl₂ · $\text{H}{}_2\text{O}\text{kg}$, i.p.) 72 hr prior to sacrifice or a single dose of Ni (59.5 mg NiCl₂ · $\text{6H}{}_2\text{O}\text{kg}$, s.c.) 16 hr prior to sacrifice. For the combined treatment, animals received the single dose of Ni 56 hr after the single dose of Cd and they were killed 16hr later.

3. Cd treatment alone did not produce any changes in the hepatic GST activities toward the substrates studied.

4. Ni treatment alone, however, significantly increased hepatic GST activity toward EAA whereas it was ineffective on GST activities for CDNB and DCNB.

5. Combined treatment of metals did not alter hepatic GST activities toward the substrates CDNB and DCNB. Hepatic GST activity for EAA, however, was significantly increased by the combined treatment. Nevertheless, the combined treatment did not augment the increase in GST activity for EAA noted by Ni treatment alone.

1. Plasma antioxidant activity was determined in rats, guinea pigs, rabbits and humans.

2. Low levels of antioxidant activity were observed in rats and guinea pigs. Both species showed high susceptibility to lipid peroxidation in red blood cells.

3. In rabbit and human plasma antioxidant activity was high. In these species, susceptibility to lipid peroxidation was low.

1. Calmitine and mitochondrial calcium were studied after injection of chlorpromazine into control and denervated gastrocnemius muscle in rat.

2. Calmitine decreased under the effect of chlorpromazine and then increased again. Regenerative capacity was more marked for denervated than control muscle. Calcium increased and then returned to its normal level in control muscle while remaining elevated in denervated muscle.

3. Thus, it would appear that calmitine synthesis can occur in the absence of innervation and that denervation, which probably causes disturbances in mitochondrial calcium regulation systems, may prevent total regeneration of muscle after an injury.

1. Addition of the β-adrenergic agonist clenbuterol to the diet of steers increased blood flow in portal-drained viscera, liver and tissues of the hindquarters.

2. Uptake of oxygen increased with clenbuterol feeding in hindquarters but not portal-drained viscera or liver.

3. On day 1 of clenbuterol feeding, the principal source of circulating l-lactate switched from portal-drained viscera to hindquarters.

4. Both net release of α-amino nitrogen by the portal-drained viscera and net uptake by the hindquarters decreased on day 1 of clenbuterol feeding. Over time of clenbuterol feeding, both release of α-amino nitrogen by the portal-drained viscera and uptake by the hindquarters increased to equal or greater than pretreatment values, respectively.

1. Administration of dexamethasone significantly reduced the amount of hepatic cytochrome P₄₅₀ in Syrian golden and Chinese hamsters, while it increased the amount in rats.

2. In contrast to rats, the induction rate of the activities of erythromycin and troleandomycin N-demethylases by dexamethasone was relatively low, while that of the testosterone 6β-hydroxylase was high in the two hamster strains.

3. Western blot analysis revealed that dexamethasone did not modify markedly the pattern of the P₄₅₀IIIA subfamily proteins in the two hamster strains.

1. We examined the effects of stizolobic acid, an amino acid isolated from a plant, Stizolobium hassjoo, on the binding of [³H]glutamic acid and [³H]kainic acid to synaptosomes from frog spinal cords and on the depolarization at the ventral roots of frog spinal cords.

2. Stizolobic acid inhibited the binding of [³H]kainic acid more potently than that of [³H]glutamic acid.

3. Among Stizolobic acid derivatives, 3-Br-stizolobic acid was the most potent inhibitor of the binding of [³H]kainic acid, but the inhibitory potency was 100 times weaker than that of kainic acid.

4. Stizolobic acid and its derivatives could cause depolarization of the ventral root of frog spinal cord in a dose dependent manner, and 3-Br-stizolobic acid was a more potent inducer of depolarization than kainic acid, but the dose dependency of 3-Br-stizolobic acid was a little different from that of kainic acid.

5. The results suggest that Stizolobic acid and its analogues act as a kainic acid agonist in frog spinal cord.

6. The present results and others indicate that Stizolobic acid may interact with the different types of excitatory amino acid receptors dependent on the species of animals.

1. The main mechanisms involved in heavy metal cation homeostasis in marine invertebrate cells are described.

2. Metallothioneins are probably the most important soluble compounds involved in heavy metal cation homeostasis. The biochemical characteristics of these metalloproteins and the relationship between their amino acid composition and heavy metal binding capacity are elucidated. Moreover data are reported concerning the physiological role of metallothioneins e.g. heavy metal detoxification, cellular metal redistribution, free radical scavenger action, etc. The possible meaning of different soluble compounds in heavy metal cation homeostasis is also discussed.

3. The biochemical role of lysosomes in heavy metal cation compartmentalization and the involvement of these organelles in metallothionein accumulation and sequestration are shown.

4. Data are reported concerning the sequestration of heavy metal cations in insoluble granules as a mechanism of metal detoxification.