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PubMed1978

Diurnal variations in the influence of the ultimobranchial glands on calcium homeostasis in the frog (Rana pipiens).

The effect of the light-darkness cycle on the efficiency of the ultimobranchial and parathyroid glands in altering duodenal calcium transport and plasma and urinary concentrations of calcium was examined in the adult male frog (Rana pipiens). Frogs were unfed, but were allowed access to 0.05 M-CaCl2 in the surrounding medium after ultimobranchialectomy or parathyroidectomy. Calcium transport, as assayed by the everted gut-sac technique, was increased in ultimobranchialectomized frogs at sunrise, concomitant with acute hypercalcaemia and hypercalciuria. An opposite but chronic response was observed in parathyroidectomized frogs with intact ultimobranchial glands. The maximum response observed at sunrise occurred when the concentration of calcium in the plasma of control frogs was decreasing; the minimum response, which occurred 6 h after sunrise, was coincident with a diurnal peak in the concentration of calcium. Vitamin D3 (500 microgram/frog) enhanced calcium transport in ultimobranchialectomized frogs, which resulted in chronic hypercalcaemia and hypercalciuria. The results suggest that diurnal variations in the plasma concentration of calcium do not initiate ultimobranchial activity, but are a response to endocrine control synchronized with the transition from darkness to light.

Animals↗
PubMed2004

Plasma sex steroid concentrations and gonadal aromatase activities in African clawed frogs (Xenopus laevis) from South Africa.

Adult African clawed frogs (Xenopus laevis) were collected from a corn-growing region (CGR) and a non-corn-growing region (NCGR) with different exposure profiles for atrazine and related triazines. Physical, chemical, and biological parameters from the catchment areas were also measured. Frogs were surveyed for possible effects of exposure to triazine herbicides on plasma testosterone (T) and estradiol (E2) titers, gonadal aromatase activity, and gonad growth (GSI). Concentrations of both T and E2 varied among locations and were correlated to some accessory factors, such as pH, several ions, and metals. Greatest median plasma T concentrations (males: 19 ng/ml; females: 16 ng/ml) occurred in frogs inhabiting NCGR as compared to those from the CGR (males: 4 ng/ml; females: 1 ng/ml). Median E2 concentrations were also greater in frogs collected from the NCGR (males: 3 ng/ml; females: 28 ng/ml) than those in frogs from the CGR (males: 2 ng/ml; females: 5 ng/ml). Because some exposure to agricultural chemicals at both regions occurred, as did simultaneous exposures to multiple chemicals, a regression analysis was employed. Negative correlations were observed between plasma T concentrations and concentrations of atrazine, deisopropylatrazine, deethylatrazine, and tertbuthylazine in females and between T and diaminochlorotriazine in males. Estradiol in females exhibited a significant negative correlation with atrazine and deethylatrazine. No correlations were observed between gonadal aromatase activity or GSI and any of the agricultural chemicals measured. Median aromatase activities in ovaries varied among sampling sites ranging from 7 to >3000 times greater than those in males when measurable. Testicular aromatase activity was below the detection limit of the assay in male frogs at most of the sites. Although exposure to agricultural inputs did not affect aromatase activities, effects of atrazine or coapplied pesticides on sex steroid homeostasis cannot be excluded at this point.

Agriculture↗
PubMed2004

Pesticides in mountain yellow-legged frogs (Rana muscosa) from the Sierra Nevada Mountains of California, USA.

In 1997, pesticide concentrations were measured in mountain yellow-legged frogs (Rana muscosa) from two areas in the Sierra Nevada Mountains of California, USA. One area (Sixty Lakes Basin, Kings Canyon National Park) had large, apparently healthy populations of frogs. A second area (Tablelands, Sequoia National Park) once had large populations, but the species had been extirpated from this area by the early 1980s. The Tablelands is exposed directly to prevailing winds from agricultural regions to the west. When an experimental reintroduction of R. muscosa in 1994 to 1995 was deemed unsuccessful in 1997, the last 20 (reintroduced) frogs that could be found were collected from the Tablelands, and pesticide concentrations in both frog tissue and the water were measured at both the Tablelands and at reference sites at Sixty Lakes. In frog tissues, dichlorodiphenyldichloroethylene (DDE) concentration was one to two orders of magnitude higher than the other organochlorines (46+/-20 ng/g wet wt at Tablelands and 17+/-8 Sixty Lakes). Both gamma-chlordane and trans-nonachlor were found in significantly greater concentrations in Tablelands frog tissues compared with Sixty Lakes. Organophosphate insecticides, chlorpyrifos, and diazinon were observed primarily in surface water with higher concentrations at the Tablelands sites. No contaminants were significantly higher in our Sixty Lakes samples.

Animals↗
PubMed1997

Stage-dependent distribution of calreticulin in oocytes of the frog, Rana rugosa.

We studied immunohistologically the distribution of a Ca2(+)-binding protein, calreticulin (CLT), at different stages of growing oocytes in the frog, Rana rugosa. Northern blot analysis showed that the CLT gene expression in gonads of metamorphosing tadpoles was low, but was extremely strong in the ovary, but not in the testis, of 2-month post-metamorphosis frogs, followed by decline to a lower level in adult frogs. On the contrary, the beta-actin gene expression did not increase in the same ovary. As for the distribution of CLT protein, a weak immunostaining was observed in indifferent gonads of tadpoles at stage I. The CLT distribution in oocytes from stage A to F was stage-dependent. In addition, Western blot analysis revealed that the CLT level was low in gonads of tadpoles at stage I, but increased at stage XVI. It still increased in the ovary of frogs 2 months after metamorphosis, and then dropped to a lower level in adult frogs. The results indicate that CLT gene expression occurs in the early stage of growing oocytes, and that CLT is synthesized actively in oocytes in the ovary of frogs after metamorphosis. Based on these findings, the role of CLT is discussed.

Actins↗
PubMed1999

Inhibition and stimulation of K+ transport across the frog erythrocyte membrane by furosemide, DIOA, DIDS and quinine.

Frog erythrocytes were incubated in iso- or hypotonic media containing 10 mmol/l Rb+ and 0.1 mmol/l ouabain and both Rb+ uptake and K+ loss were measured simultaneously. Rb+ uptake by frog red cells in iso- and hypotonic media was reduced by 30-60% in the presence of 0.01-0.1 mmol/l [(dihydroindenyl)oxy] alkanoic acid (DIOA) or 0.5-1.0 mmol/l furosemide. Furosemide inhibited K+ loss from frog erythrocytes incubated in hypotonic media but did not affect it in isotonic media. DIOA at a concentration of 0.05 mmol/l inhibited of K+ loss from frog erythrocytes in both iso- and hypotonic media. At the concentrations of 0.01 and 0.02 mmol/l DIOA significantly suppressed K+ loss in a K+-free chloride medium but not in a K+-free nitrate medium. The Cl(-)-dependent K+ loss was completely blocked at a concentration of 0.1 mmol/l DIOA and the concentration required for 50% inhibition of K-Cl cotransport was approximately 0.015 mmol/l. However, the inhibitory effect of DIOA on K-Cl cotransport was masked by an opposite stimulatory effect on K+ transport which was also observed in nitrate medium. Quinine in a concentration of 0.2-1.0 mmol/l was able to inhibit Rb+ uptake and K+ loss only in hypotonic media. In isotonic media, quinine produced a stimulation of Rb+ uptake and K+ loss. A three to five-fold activation of Rb+ uptake and K+ loss was consistently observed in frog erythrocytes treated with 0.05-0.2 mmol/l 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). In contrast, another stilbene derivative 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid (SITS) had no effect on K+ transport in the cells. Thus, of these drugs tested in the present study only DIOA at low concentrations may be considered as a selective blocker of the K-Cl cotransporter in the frog red blood cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2000

Rhodanese activity and total sulfur content in frog and mouse liver.

The activity of rhodanese was histochemically tested in cryostat sections of the frog (Rana temporaria) and mouse liver. The activity levels were evaluated in sections, and the results were expressed as the ratio of the area of all granules, products of the enzymatic test, to the total analyzed area (area fraction). The present study confirmed the biochemically detected activity of rhodanese, and showed a large pool of endogenous sulfane sulfur donors, substrates for rhodanese, in the frog liver. The area of a single granule corresponded to the size of the mitochondrium, what suggests enzyme localization in this organelle. In view of this it should be considered whether the rhodanese activity, biochemically detected in the cytosolic fraction of the frog liver, results from the enzyme action. The total content of sulfur in cryostat sections of the mouse and frog liver was calculated and compared on the basis of the Energy Dispersion Spectrum (EDS) obtained by a scanning microscope. These studies showed higher total sulfur content in the frog liver than in the mouse liver. The high total content of sulfur in the frog liver in autumn might be associated with sulfur storing for protein biosynthesis during the period of hibernation.

Animals↗
PubMed2002

Frequency of feeding and formation of bone growth marks in frog, Rana cyanophlyctis (Schn.).

Frogs, R. cyanophlyctis (n = 45) divided into four groups, were exposed to different feeding regimens (live guppies were used as food) such as, daily, alternate day, every fourth day and weekly feeding for 5 months, during wet months of the year (April-September). Two toe clippings were made, one at the beginning and the other at the termination of the experiment. Clipped toes were demineralized, and processed for histology. In 6 out of 45 frogs one line of arrested growth (LAG) was present in the phalangeal histology at the beginning of the experiment while, at the termination of experiment 34 out of 43 frogs exhibited one LAG each indicating that in 26 frogs LAG appeared freshly during the experimental period. The fact that LAGs are formed in regularly fed frogs suggests the humid weather/seasonal rainfall may play relatively important role than the feeding in cyclic bone growth and formation of growth marks in this frog.

Animals↗
PubMed1992

Flavobacterium indologenes infection in leopard frogs.

An investigation of an epidemic of infectious disease in a frog (Rana pipiens) colony was conducted. Six of 40 frogs in a continuous (once through) water flow housing system had weight loss, swollen abdomen, corneal edema, uveitis, subcutaneous edema, petechial hemorrhage, incoordination, and respiratory distress. The frogs had lesions consistent with bacterial septicemia. A gram-negative, nonfermenting bacillus, Flavobacterium indologenes (Flavobacterium sp biovar IIb), was isolated in pure culture from tissues and blood. The clinical isolate was used to inoculate healthy frogs sc. An isolate identical to the one isolated from the sick frogs was recovered from tissues and blood of the inoculated frogs. Inoculation of the housing water in a nonflow-through system did not result in disease, despite proliferation of the Flavobacterium spp in the water; therefore, it is likely that establishment of infection requires the presence of the organism in sufficient numbers and a portal of entry into the body.

Animals↗
PubMed2004

Cutaneous acariasis in the African clawed frog (Xenopus laevis).

Increased mortality was observed in a single colony of 50 Xenopus laevis. The frogs were used as oocyte donors in developmental biology studies. Necropsy findings included dermal erythema and petechiation consistent with red leg syndrome; dermal ulcerations and white, filamentous growths on the skin were consistent with Saprolegnia sp. Microscopic evaluation of the skin and fungus revealed an astigmatid mite similar to those of the genus Rhizoglyphus. The mite was also found in the water and the biological filter of the tanks housing the frogs. This mite is considered not to be a parasite of X. laevis; instead, it feeds off moss, fungi, and detritus. Subsequent evaluation of the sphagnum moss used for shipping the frogs from the supplier revealed the same mite in the moss. Our hypothesis is that the mite was introduced into the tank with the shipment of new frogs in sphagnum moss. The mites lived within the biological filter, and were only found after the growth of Saprolegnia sp. attracted the mites to the frogs. Laboratory animal care and veterinary personnel should consider non-pathogenic species of mites in the differential diagnosis of acariasis in Xenopus frogs.

Acaridae↗
PubMed1991

Helminth infracommunities of the frogs Rana catesbeiana and Rana clamitans from Turkey Marsh, Michigan.

One hundred twenty-seven bullfrogs, Rana catesbeiana, and 120 green frogs, Rana clamitans, collected in July and August 1987 from Turkey Marsh, Michigan, were examined for helminths. Of the 16 helminth species found, Falcaustra catesbeianae had the highest prevalence and mean intensity in bullfrogs. In green frogs, Megalodiscus temperatus had the highest prevalence and Haematoloechus parviplexus had the highest mean intensity. Taxonomically, 1,030 (30.5%) trematodes and 2,348 (69.5%) nematodes occurred in bullfrogs; 2,874 (96.4%) trematodes, 2 (0.1%) cestodes, and 105 (3.5%) nematodes were found in green frogs. The larger and more aquatic of the 2 hosts, R. catesbeiana, had the highest mean number of helminth species, helminth intensity, diversity, and evenness. Adult frogs of both species had a significantly higher mean number of helminth species than did juveniles. Significant correlations existed between the number of helminth species and frog length. Although the helminth communities of Turkey Marsh frogs are isolationist in character, they are more diverse than other helminth communities studied in amphibians.

Animals↗
PubMed1975

Identification of adenylate cyclase-coupled beta-adrenergic receptors in frog erythrocytes with (minus)-[3-H] alprenolol.

(minus)-Alprenolol, a potent, competitive beta-adrenergic antagonist labeled to high specific activity with tritium (17 Ci per mmol), has been used to identify binding sites in frog erythrocyte membranes having many of the characteristics to be expected of the beta-adrenergic receptors which are linked to adenylate cyclase in these membranes. The chromatographic behavior and biological activity of the labeled and native drug were essentially identical. (minus)-Alprenolol and (minus)-[3-H]alprenolol both competitively antagonize isoproterenol stimulation of frog erythrocyte membrane adenylate cyclase with a KD OF 5 TO 10 NM. (minus)-[3-H]Alprenolol binding to sites in the frog erythrocyte membranes was studied by a centrifugal assay. At 37 degrees, equilibrium binding was established within 5 min and the half-time for dissociation of bound (minus)-[3-H]alprenolol was approximately 30 s. This rapid onset and dissociation of (minus)-[3-H]alprenolol binding was in good agreement with the rapid onset of action of beta-adrenergic agonists and antagonists on the frog erythrocyte adenylate cyclase. (minus)-[3-H]Alprenolol binding was saturable. There were 0.25 to 0.35 pmol of (minus)-[3-H]alprenolol binding sites per mg of protein corresponding to 1300 to 1800 binding sites per intact frog erythrocyte. The binding sites showed half-maximal saturation at 5.0 to 10 nM (minus)-[3-H]alprenolol, which is in good agreement with the KD for alprenolol antagonism of isoproterenol stimulation of adenylate cyclase. The (minus)-[3-H]alprenolol binding sites exhibited strict stereospecificity. (minus)-Stereoisomers of beta-adrenergic antagonists or agonists were approximately 2 orders of magnitude more potent than the (+)-stereoisomers in competing for the binding sites. Comparable stereospecificity was apparent when agonists and antagonists were tested for their ability to interact with the adenylate cyclase-coupled beta-adrenergic receptors in the membranes. Potency series of 11 agonists and 13 antagonists for inhibition of binding and interaction with adenylate cyclase were identical and were characteristic of a beta2-adrenergic receptor. A variety of nonphysiologically active compounds containing a catechol moiety as well as several metabolites and cholinergic agents did not inhibit (minus)-[3-H]alprenolol binding or interact significantly as agonists or antagonists with the adenylate cyclase. The (minus)-[3-H]alprenolol binding sites studied appear to be equivalent to the beta-adrenergic receptor binding sites in the frog erythrocyte membranes.

Adenylyl Cyclases↗
PubMed1988

Isolation of terminal cisternae of frog skeletal muscle. Calcium storage and release properties.

Sarcoplasmic reticulum (SR) terminal cisternae (TC) of frog (Rana esculenta) fast-twitch skeletal muscle have been purified by isopycnic sucrose density gradient centrifugation. Biochemical characteristics and Ca2+ release properties have been investigated and compared to those of the homologous fraction of rabbit skeletal muscle TC. The frog SR fraction obtained at the 38/45% sucrose interface appears to be derived from the terminal cisternae region as judged by: (a) thin section electron microscopy showing vesicles containing electron opaque material and squarelike (feet) projections at the outer surface; (b) protein composition (Ca2+-ATPase, calsequestrin, and high Mr proteins); (c) Ca2+ fluxes properties. The content of calsequestrin was higher in frog TC by 50% and the Ca2+ binding capacity (624 or 45 nmol of Ca2+/mg of TC protein, depending upon experimental conditions) was 3-4 times that of rabbit TC. Species-specific antigenic differences were found between junctional SR proteins of frog and rabbit TC. After active Ca2+ preloading in the presence of pyrophosphate (Palade, P. (1987) J. Biol. Chem. 262, 6135-6141), caffeine and doxorubicin elicited Ca2+ release from either TC fraction but with much faster rates in frog TC than in rabbit TC (14 versus 3 mumol of Ca2+/min/mg of protein). The present results provide new evidence for the existence of marked differences in Ca2+ release properties between TC of amphibian and mammalian fast-twitch muscle. Higher Ca2+ binding capacity and faster release rates in frog TC might compensate for the comparably greater diffusion distance being covered by the released Ca2+ from the Z-line to the actomyosin cross-bridges in the A-I overlap region.

Animals↗
PubMed1978

The properties of the extraocular muscles of the frog. I. Mechanical properties of the isolated superior oblique and superior rectus muscles.

The mechanical properties of two extraocular muscles (superior oblique and superior rectus muscles) of the frog were studied and compared with those of a frog's skeletal muscle (iliofibularis muscle) which contains the same types of muscle fibres as the oculorotatory muscles. The extraocular muscles are very fast twitching muscles. They exhibit a smaller contraction time, a smaller half-relaxation time, a higher fusion frequency, and a lower twitch-tetanus ratio than the skeletal muscles. The maximum isometric tetanic tension produced per unit cross-sectional area is lower in the extraocular muscles than in skeletal muscles. However, the extraocular muscles show a higher fatigue resistance than the skeletal muscles. With respect to the dynamic properties there are some differences between the various oculorotatory muscles of the frog. The superior rectus muscle exhibits a faster time-course of the contraction, a higher fusion frequency, and a higher fatigability than the superior oblique muscle. An increase of the extracellular K+-concentration evokes sustained contractures not only in the extraocular muscles but also in the iliofibularis muscle; between these muscles there are no striking differences in the mechanical threshold of the whole muscle preparation. The mechanical threshold depends on the Ca++-concentration of the bathing solution and it is found in a range between 12.5 and 17.5 mM K+ in a normal Ringer solution containing 1.8 mM Ca++. The static-mechanical properties of the extraocular muscles of the frog and the dependence of the active developed tension on the muscle extension are very similar to those which are known to exist in the extraocular muscles of other vertebrates. In tetanic activated frog's oculorotatory muscles a linear relationship exists between length and tension. A variation of the stimulation frequency does not change the slope of this curve but causes parallel shifts of the curve. The peculiar properties of the extraocular muscles of the frog are discussed with respect to the muscle fibre types in these muscles and to the diameter of the muscle fibres.

Animals↗
PubMed1979

Structural studies of natural actomyosin from thermally acclimated frogs.

Natural actomyosin was isolated from skeletal muscle of frogs (Rana catesbeiana) acclimated at 25 degrees C and 5 degrees C. It was found that preparations isolated from warm-acclimated frogs may display considerable degradation of myosin heavy chains as compared with preparations isolated from cold-acclimated frogs. However, degradation may be minimized by inclusion of protease inhibitors during purification, indicating enhanced protease activity in preparations of natural actomyosin from warm-acclimated frogs. When purified in the presence of protease inhibitors, natural actomyosin from both warm-acclimated and cold-acclimated frogs exhibits comparable subunit composition of SDS-gel electrophoresis. The overall gel pattern is similar to that obtained from rabbit natural actomyosin except that in the frog, troponin-T and troponin-C appear to co-migrate with tropomyosin and myosin light chain 2, respectively.

Acclimatization↗
PubMed1984

The onset and offset of the hydrosmotic response in frog epithelia.

The onset and offset of the hydrosmotic responses elicited by different agonists in frog urinary bladder, frog skin and isolated frog skin epithelium were studied and compared. The removal of the frog skin supporting layers accelerated the onset of the reactions to oxytocin and 8-bromo-cyclic AMP (8-Br-cAMP), which, however, remained slower than the onset in the urinary bladder. The offset of these actions was not affected by corion removal and was also slower than in the bladder. A marked asymmetry between onset and offset of the hydrosmotic response was observed when the isolated skin epithelium was stimulated with 8-Br-cAMP. The results show that the increases in water permeability elicited by oxytocin and cyclic-AMP derivatives in frog skin and frog urinary bladder, although attributable to the same general mechanisms, present different specific characteristics.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1983

The frog palate for studying mucus transport velocity and mucociliary frequency.

The palate of the frog possess a pseudostratified epithelium with mucus secreting cells and numerous ciliated cells covered with a continuous mucus blanket of 4 to 8 micron thickness. This palate can be used as a simple model for studying mucus transport and giving rapid information on the transportability of pathological bronchial secretion by the ciliary mechanism. The analysis of the relationship between the rheological properties of sputum an their transport rates on the frog palate showed that the highest transport rates were obtained with sputum samples characterized by a high spinability (Sp greater than 70 mm) and an intermediate range of viscosity (25-180 P) and elasticity (SR = 4-12 units). The mucociliary frequency (Fm) of the frog palate was measured by a photoelectric method and analyzed as a distribution function of the ciliary frequencies by the Fast Fourier Transform method. Fm decreased significantly after mucus depletion and was restored when adding a drop of frog mucus collected on a freshly excised frog palate. On the other hand, it remained about 20% lower than the original predepleted value, when adding purulent sputum collected in patients with chronic bronchitis and cystic fibrosis. The frog palate appears as a valuable model for analyzing the mucociliary transport rate and also for studying the effect of pathological secretions on the ciliary beating frequency.

Animals↗
PubMed1981

The effect of laser irradiation on the frog pineal.

The frog pineal is a functional photoreceptor with probable endocrine capabilities. Continuous wave Laser radiation at 514.5 nanometers for 300 sec at 200 mW, as focused on the pineal of the intact frog Rana esculenta to study the functional role of this structure. The investigation was carried out on 80 male specimens - 40 of which were controls - in light and in dark experimental conditions - during the months of March, July and November. The ratio gonad weight/body weight was used to measure the effect of the Laser. The response was consistently similar from control frogs kept in the dark and from Laser-irradiated frogs kept in the light. The same was observed in the opposite situation. Histological examination showed structural modifications of the gonads and skin of Laser-irradiated frogs. These results suggest a functional correlation between the pineal photoreceptor cells and the pineal secretory cells. We hypothesize that the pineal itself might influence gonadal activity through the secretion of an hormone within the third ventricle. The frog's skin did not change colour during the Laser irradiation, we therefore suppose that the structures responsible for the release of the hormone regulating colour changes are not effected by the Laser beam.

Animals↗
PubMed1996

Kinetics of acetyl coenzyme A:arylamine N-acetyltransferase from rapid and slow acetylator frog tissues.

N-acetyltransferase (NAT) activity was determined in 100 frog (Rana tigrina) livers using 2-aminofluorene and p-aminobenzoic acid as substrates. Overall, the liver NAT activity of the 50 females was higher than the liver NAT activity of the 50 males. The activities (mean +/- SD) of NAT from the bladder, blood, colon, and liver of males was 0.30 +/- 0.11, 0.05 +/- 0.03, 0.09 +/- 0.05, and 0.93 +/- 0.56 nmol/min/mg protein for the acetylation of aminofluorene and 0.29 +/- 0.06, 0.36 +/- 0.04, 0.26 +/- 0.02, and 0.32 +/- 0.14 nmol/min/mg protein for the acetylation of p-aminobenzoic acid. In the bladder, blood, colon, and liver from female frogs, the activities obtained were 1.00 +/- 0.41, 0.52 +/- 0.07, 0.08 +/- 0.05, and 1.27 +/- 0.49 nmol/min/mg protein for aminofluorene and 0.34 +/- 0.12, 0.36 +/- 0.04, 0.34 +/- 0.07, and 0.48 +/- 0.21 nmol/min/mg protein for p-aminobenzoic acid. Kinetic constants for arylamine NAT activity in the blood, liver, bladder, and colon from frogs with rapid, intermediate, and slow acetylator activities were determined. KM and Vmax values for aminofluorene were 2- to 6-fold higher for liver than for the other tissues. KM and Vmax values for p-aminobenzoic acid showed a smaller variation among the tissues examined, with values obtained for the liver and bladder being somewhat higher than the values for the blood and colon. An apparent KM difference for aminofluorene was found in the liver from frogs with high and low acetylator activity. Based on the aminofluorene NAT activity of liver, there seems to be a polymorphism in NAT activity with 4 rapid, 21 intermediate, and 75 slow acetylators among the 100 frogs assayed. Distribution of acetylator phenotypes was similar among the 50 males and 50 females in this study. This is the first demonstration of acetyl coenzyme A:arylamine NAT activity in an amphibian and could lead to the development of a frog model for monitoring the effect of pollution of wetland environments on native species.

Acetyl Coenzyme A↗