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Toad
About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.
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TL;DR: Novel findings in the toad testis are reported using freeze‐fracture techniques and the fact that they are present in amphibia might indicate that they represent a widespread pattern.
Abstract: The present work reports novel findings in the toad testis using freeze-fracture techniques. Tight and gap junctions are observed in the nonfenestrated endothelial cells. Numerous gap junctions are present between interstitial cells. Sertoli-Sertoli junctional specializations in the toad are similar to those described in mammals although they appear to be less elaborate. The appearance of nuclear pores, in the seminiferous epithelium, ranges from a uniformly and apparently random distribution in Sertoli cells to large aggregations of closely spaced pores separated by free areas in the nuclear envelope of spermatocytes. Inasmuch as these features have also been described in mammals, the fact that they are present in amphibia might indicate that they represent a widespread pattern.
Concomitantly with increasing chromatin condensation, nuclear pores diminish in round spermatids and seem to disappear in the more mature germ cells. The en face freeze-fracture views of annulate lamellae in the postnuclear cytoplasm and membranous features of the acrosome formation, flagellum, and undulating membrane of elongating spermatids are also described.
10 citations
TL;DR: The present results furnish an explanation for the previous findings, i.e. good yield of binding to (digitonin/NaCl) solubilized binding sites from rat brain can only be obtained with labeled opiate antagonists, and explain why good yields ofbinding to the soluble opioidbinding sites from toad brain can be obtained in the absence of sodium.
10 citations
TL;DR: The respiratory quotient of metabolism associated with sodium transport in the toad bladder may be greater than 1.0 and this tissue was directly examined to directly examine the respiratory quotients of this tissue.
Abstract: IT has been inferred1 that the respiratory quotient of metabolism associated with sodium transport in the toad bladder may be greater than 1.0. We have therefore directly examined the respiratory quotient of this tissue.
10 citations
TL;DR: The data indicate that tropical fishes may have reduced xenobiotic-metabolizing ability compared to the rat and amphibians, and the use of sodium dithionate as a reducer, rather than NADPH, may be preferential in b5 determinations.
Abstract: We performed a comparative analysis of cytochrome P450, cytochrome b5, MFO associated enzymes and cytosolic antioxidant enzymes in hepatic microsomes and cytosolic fractions prepared from five animal species representing three vertebrate classes living in tropical conditions (Brazil). The data obtained show that rats have higher hepato-somatic index, specific cytochrome b5 concentration, and NADPH-dependent cytochrome c (P450) activity compared to ectothermic species, SOD activity similar to those in amphibians, and specific concentration of cytochrome P450 and catalase activity lower than in a toad, but higher than in fishes and a frog. Our data indicate that tropical fishes may have reduced xenobiotic-metabolizing ability compared to the rat and amphibians. In contrast to fish and rat, amphibians have a low ratio (<0.5) of cytochrome b5 concentration to that of P450. Most species showed cytochrome b5 sensitivity to oxygen. Thus, the use of sodium dithionate as a reducer, rather than NADPH, may be preferential in b5 determinations.
10 citations
10 citations