Mutagenic carcinogens and noncarcinogens in transgenic mice.
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Animals↗
Biomedical subjects
P Günzel
Publications and source records attributed to P Günzel.
Commentary on the publication: Tucker MJ, Jones DV. Effects of cyproterone acetate in C57B1/10J mice.
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Animals↗
Animal toxicity studies performed for risk assessment of the once-a-month injectable contraceptive Mesigyna.
Results from toxicity studies performed for risk assessment of the combined injectable hormonal preparation Mesigyna are reviewed. Both components of Mesigyna, i.e., estradiol valerate (E2Val) and norethisterone enanthate (NET-EN), have been thoroughly investigated as individual compounds and some limited toxicity data have been obtained for the combination. Most findings which were gathered in these studies from different animal species occurred in the gonads, accessory genital and endocrine organs and can be related to the known species-specific pharmacological activity of a typical estrogen or progestin, respectively. No additional or unexpected information which might indicate a possible estrogen/progestin interaction was gained from the administration of the combined preparation to animals. Based on the results from toxicity testing, there were no objections to the long-term therapeutic use of Mesigyna for hormonal contraception. The predictive value of the effects (including the tumorigenicity) observed in the common laboratory animals with regard to human safety is critically discussed, taking the vast amount of previous experience with hormonal contraceptives into consideration. The conclusion is drawn that there is no animal model for safety assessment of sex steroids that adequately represents the human situation. Quantitative extrapolations from animal toxicity findings to humans, therefore, are not possible. Especially, the value of long-term studies and of toxicity studies on estrogen/progestin combinations is put into question. Like endocrine pharmacology studies, the toxicity studies with these steroid hormones are useful for the characterization of the possible endocrine pharmacological profile only.
Animals↗
Effect of norethisterone acetate on serum lipid and lipoprotein parameters as well as on blood coagulation in female monkeys (M. fascicularis).
The effects of daily oral administration of a high dose of 10 mg norethisterone acetate (NET-Ac.)/kg/day over 14 weeks on serum lipid and lipoprotein parameters as well as on blood coagulation were investigated in female monkeys (M. fascicularis). Measurements of lipids and lipoprotein cholesterol were performed in weeks--5 and -1 before treatment and in weeks 4, 8 and 12 after treatment. In addition, various blood coagulation and fibrinolytic parameters were determined in weeks 11-14 after treatment with NET-Ac. Furthermore, the serum levels of norethisterone (NET) were determined in order to monitor the real systemic compound exposure and revealed that Cmax and AUC (0-3 h) values reached for norethisterone in this experiment in monkeys were about 25 times higher than those obtained after an oral contraceptive dose of NET-Ac. in women. The results of lipid and lipoprotein cholesterol determinations showed decreases in serum total lipids, phospholipids, triglycerides and total cholesterol associated with similar decreases in HDL-, LDL- and VLDL-cholesterol fractions after NET-Ac.-treatment in monkeys. These effects were observed from week 4 onwards and maintained their magnitude up to week 12 after treatment. Since both HDL- and LDL-cholesterol fractions decreased, the HDL/LDL-ratio remained almost unchanged. Thus, the results obtained in this study after high-dose treatment with NET-Ac. in monkeys did not indicate any changes of lipid and lipoprotein parameters which in humans are supposed to be associated with an increased risk of cardiovascular lesions, namely a decrease in HDL- and increase in LDL-cholesterol fractions. The results of blood coagulation and fibrinolytic parameters showed increased antithrombin-III and plasminogen levels besides minor changes in other parameters, thus indicating that NET-Ac.-treatment does not contribute to an increased risk of cardiovascular thrombotic events in the cynomolgus monkey.
Animals↗
Serum lipoprotein pattern in rats, dogs and monkeys, including method comparison and influence of menstrual cycle in monkeys.
The serum lipoprotein pattern (HDL-, LDL- and VLDL-cholesterol) was determined in normal untreated rats, dogs and monkeys using the density gradient centrifugation method, and compared with that in humans. The serum of rats (Wistar) and dogs (Beagle) was found to contain mainly HDL-cholesterol, whereas the serum of monkeys (Macaca fascicularis) consists of similar amounts of HDL-cholesterol and LDL-cholesterol, as in humans. In contrast to rats and dogs, monkeys showed a very low amount of serum VLDL-cholesterol. Comparison of four different methods (density gradient centrifugation, FPLC, agarose gel electrophoresis and precipitation methods) for determination of HDL- and LDL-cholesterol in monkey serum showed that density gradient centrifugation and FPLC-methods have the highest accuracy and recovery rate. The FPLC-method offers the extra advantages that it requires less sample volume and is less laborious. In a separate experiment, the influence of the menstrual cycle on the serum lipoprotein pattern was investigated in female monkeys. No changes in total cholesterol, HDL- or LDL-cholesterol were detected in serum samples obtained in the follicular and luteal phases of the cycle. In conclusion, monkeys (Macaca fascicularis) may be more suitable than rats or dogs for the comparison of the effect of different compounds on serum lipoproteins in pharmacological and toxicological studies, because the lipoprotein pattern in this species is similar to that of humans.
Animals↗
ZK 90 695: a new antiarthritic drug with tissue targeting properties.
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Animals↗
Considerations regarding the development of individual nonclinical test strategies in the European Community.
The wish of pharmaceutical companies to be given the most binding possible preclinical test programmes for a new product, and the tendency of authorities to regulate to a great extent the preclinical testing of new drugs (especially at a multinational level), has led to differing requirements and practices in preclinical testing in different areas of the world. These differing requirements and practices have of necessity brought in their wake varying scientific criteria, with particular regard to animal protection, ethical standards, as well as imposing apparently unjustified extra financial costs. In order to improve this situation, the development of drug-specific preclinical test strategies is proposed in a drafted E. C. Note for Guidance, which incorporates already existing drug-testing guidelines and method recommendations. This draft Note for Guidance points to general methods of analysing problems and reaching decisions and thus appears to be worthy of recommendation as practical and desirable. It requires the co-operation of drug producers and supervisory authorities at a high scientific and ethical level. With regard to the state-of-the art and the socio-political background, the fulfillment of these requirements would appear not only to be appropriate but also imperative. To put them into practice would contribute enormously to the improvement of drug development and to de-emotionalization of the public debate. Therefore, comments on these draft guidelines from societies and associations are urgently sought and awaited with keen interest.
Animals↗
The use of urinary N-acetyl-beta-D-glucosaminidase (NAG) for the detection of contrast-media-induced 'osmotic nephrosis' in rats.
Excretion of urinary N-acetyl-beta-glucosaminidase (NAG), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and gamma-glutamyltransferase (gamma-GT) was studied following single intravenous administrations of a non-ionic monomeric contrast medium (iohexol) at doses of 5.0, 7.5, 10.0 and 12.5 g iodine/kg body wt in rats. Measurements of urinary enzymes, serum urea nitrogen and serum creatinine were carried out on the 2nd, 3rd, 4th and 8th days after treatment. Histological examinations of kidneys were performed on days 3 and 8. From 5.0 g iodine/kg onwards urinary NAG showed a dose-dependent and significant (multiple comparison, alpha = 0.05) increase in the first 18-h urine samples after application. A significant increase in urinary LDH could be observed only at the highest dose of 12.5 g iodine/kg. All other biochemical parameters showed no differences when compared to the control group. The dose-dependent increase in lysosomal NAG correlated with the histological findings, i.e. there was dose-dependent vacuolization of proximal tubular cells, so-called 'osmotic nephrosis'.
Acetylglucosaminidase↗
Effect of iloprost on serum creatine kinase and lactate dehydrogenase isoenzymes after isoprenaline-induced cardiac damage in rats.
The effect of iloprost was investigated in an experimental model of cardiac damage in rats after isoprenaline (isoproterenol) treatment. Iloprost was administered by continuous subcutaneous infusion at a dose of 0.44 micrograms/kg body weight (b.w.)/min over a total period of 9 days. On day 8, 5 mg isoprenaline/kg b.w. was applied subcutaneously to induce the cardiac damage. The determinations of creatine kinase (CK, EC 2.7.3.2) and CK isoenzymes, lactate dehydrogenase (LDH, EC 1.1.1.27) and LDH isoenzymes as well as a-hydroxybutyrate dehydrogenase (a-HBDH, no EC) were performed 2, 6 and 24 h after isoprenaline application. Immediately after the last blood sampling, the animals were sacrificed and the hearts were examined histologically. Iloprost-pretreated animals showed a reduction in the rise in heart-specific isoenzymes CK-MB and LDH1-3 in the serum after isoprenaline application. A decrease in isoenzymes CK-BB and LDH4-5 in the serum was also observed in iloprost-pretreated rats. However, no difference could be detected histologically in the extent of myocardial necrosis between animals treated with isoprenaline alone or in combination with iloprost. These results suggest a biochemical cardioprotective effect of iloprost in this rat model after isoprenaline application and the lack of correlation with histological findings is discussed.
Animals↗
Effect of three non-ionic contrast media on rats and rabbits with regard to renal changes. Interspecies comparison.
The effect of three non-ionic contrast media (iosimide, iopamidol and iopromide) was investigated in rabbits and rats after single i.v. application up to high doses with regard to renal changes. Determinations of serum urea nitrogen and creatinine and urinary enzymes (lactate dehydrogenase, gamma-glutamyl-transpeptidase and N-acetyl-beta-D-glucosaminidase) as well as histological examinations of the kidneys were performed. The results obtained demonstrate that rabbit as an experimental animal was more sensitive than rat in exhibiting renal changes to contrast media. Furthermore, determinations of urinary enzymes demonstrated that gamma-GT in rabbits and LDH in rats were the most sensitive indicators for detection of early kidney damage. With regard to the high dose levels required, these kidney changes do not indicate any risk to humans at diagnostic dose levels.
Animals↗
Diagnostic value of serum creatine kinase and lactate dehydrogenase isoenzyme determinations for monitoring early cardiac damage in rats.
Serum activities of creatine kinase (CK, EC 2.7.3.2) and CK isoenzymes, lactate dehydrogenase (LDH, EC 1.1.1.27) and LDH isoenzymes, alpha-hydroxybutyrate dehydrogenase (alpha-HBDH, no EC) and the LDH/alpha-HBDH ratio were studied following a single s.c. application of 5-250 mg isoproterenol/kg body weight (b.w.) in rats. Measurements of the serum enzymes and histological and enzyme-histochemical examinations of hearts were performed 2, 4, 6, 8 and 24 h after treatment. A drastic increase in serum levels of the isoenzymes CK-MB, LDH1, LDH2 and alpha-HBDH and decrease in the ratio LDH/alpha-HBDH were observed from 2 h onwards after isoproterenol application in all dose groups, the maximum effect being after 4-8 h. Focal cellular injury in the myocardium could also be observed from 2 h onwards after isoproterenol application by an enzyme-histochemical method using nitro blue tetrazolium (NBT) whereas the earliest histological alterations using haematoxylin and eosin (HE) stain could be detected 6 h after treatment. A dose-dependent effect as to enzyme values as well as to myocardial necrosis was observed 24 h after isoproterenol application. No kidney damage could be detected on the basis of serum urea nitrogen and histological examinations. Thus, measurement of serum activities of CK-MB isoenzyme alone or LDH1-2 isoenzymes in combination with other tests to exclude kidney damage are valuable indicators of cardiac lesions in rats.
Animals↗
Embryotoxicity of sex steroidal hormone combinations in nonhuman primates: I. Norethisterone acetate + ethinylestradiol and progesterone + estradiol benzoate (Macaca mulatta, Macaca fascicularis, and Papio cynocephalus).
Two sex steroid hormone combinations which have been used clinically as tests for detection of early pregnancy were examined for embryotoxic effects in macaques and baboons. Norethisterone acetate and ethinyl estradiol (NEA + EE) were orally administered to rhesus and cynomolgus monkeys and baboons at dosages ranging from one to 1,000 times the human dose equivalent (HDE) during days 20-50 of pregnancy. Progesterone and estradiol benzoate (P + EB) were delivered by two to six intramuscular injections to rhesus and cynomolgus monkeys between gestational days 20 and 35 at 0.1-25 X HDE. Fetuses were examined following cesarean section at 100 +/- 2 days (NEA + EE) or at term (P + EB). The results showed increased embryolethality over controls at 100-1,000 X HDE (NEA + EE) and at 10 and 25 X HDE (P + EB). Besides growth retardation, isolated cases of minor nongenital malformations were observed only in cynomolgus monkeys following treatment with both hormone combinations mainly at embryolethal dose levels and were considered spontaneous in nature. Virilization of female cynomolgus fetuses following NEA + EE treatment was manifested as two cases of clitoral enlargement in the 300 X HDE group and two cases of increased anogenital distance with reduced vaginal opening in the 1,000 X HDE group. The highest dose of NEA + EE was also maternally toxic, as two maternal deaths occurred at the end of the treatment period. One dead female cynomolgus fetus exposed to P + EB (10 X HDE) also exhibited masculinized external genitalia.(ABSTRACT TRUNCATED AT 250 WORDS)
Abnormalities, Drug-Induced↗
Embryotoxicity of sex steroidal hormones in nonhuman primates: II. Hydroxyprogesterone caproate, estradiol valerate.
Two sex steroid compounds which have been used clinically for parenteral supportive therapy of pregnancy were examined for embryotoxic effects in rhesus and cynomolgus macaques. Hydroxyprogesterone caproate (HPC) alone or in combination with estradiol valerate (EV) were administered intramuscularly (i.m.) to pregnant monkeys at 7-day intervals between 20 and 146 days of gestation and fetuses were examined following cesarean section at 150 +/- 2 days. HPC alone was tested in both species at doses ranging from 0.01 X to 10 X the human dose equivalent (HDE); only rhesus monkeys were exposed to the HPC + EV combination at 0.1 X to 10 X HDE. Total embryolethality resulted following the administration of HPC alone and combined with EV at 1 X and 10 X HDE in rhesus monkeys; the level of abortions in cynomolgus monkeys exposed to HPC (0.1 X to 1 X HDE) was comparable to controls. A small number of nonspecific malformations and developmental variations observed in cynomolgus fetuses after HPC exposure were considered to be incidental findings. No anomalies were found in surviving rhesus monkey fetuses treated with HPC + EV. The results indicate that long-term in utero exposure to the progestin, HPC, alone or in combination with EV in rhesus and cynomolgus monkeys, is embryolethal but not teratogenic at doses up to ten times the human therapeutic dose.
17 alpha-Hydroxyprogesterone Caproate↗
Value of enzyme determinations in urine for the diagnosis of nephrotoxicity in rats.
Excretion of urinary lactate dehydrogenase (LDH, EC 1.1.1.27), gamma-glutamyltransferase (gamma-GT, EC 2.3.2.2), alkaline phosphatase (ALP, EC 3.1.3.1), alanine aminopeptidase (AAP, EC 3.4.11.-), alanine aminotransferase (GPT, EC 2.6.1.2) and N-acetyl-beta-D-glucosaminidase (NAG, EC 3.2.1.30) was studied following a single i.v. application of 1 mg mercuric chloride/kg body weight or a radio contrast medium (SH H 340 AB) at a dose of 7.5 g iodine/kg body weight in rats. Measurements of urinary enzymes and serum urea nitrogen and creatinine were carried out on the second, third, fourth and ninth days after treatment. Histological examinations of kidneys were performed on day 9. A drastic increase in urinary LDH and moderate increase in gamma-GT, ALP and AAP and a very slight increase in GPT was observed in the first 18-h urine samples after mercuric chloride. This increase in enzymuria was associated with a drastic increase in serum urea nitrogen and creatinine, with a maximum on day 4. The radio contrast medium-treated animals showed a similar but less pronounced pattern of urinary enzymes excretion and only a slight increase of serum urea nitrogen on day 2. A good correlation was found between histological findings and enzymuria as well as serum urea nitrogen and creatinine. Thus, determination of only some urinary enzymes (LDH and gamma-GT) is valuable in predicting early nephrotoxicity and sufficient for the diagnosis of proximal tubule damage in rats.
Acetylglucosaminidase↗
Effect of tumor promoting contraceptive steroids on growth and drug metabolizing enzymes in rat liver.
Liver tumor formation in rats treated with oral contraceptive steroids for long periods has been associated with the tumor promoting potential of these agents. As other known liver tumor promoters, e.g., phenobarbital and hexachlorocyclohexane, induce liver growth and hepatic monooxygenases, we investigated whether or not estrogens have similar effects. Female rats were treated with a wide range of doses of ethinylestradiol, including human contraceptive doses, which are approximately 1 microgram/kg. The physiological estrogen estradiol was studied for comparison. Also included were norethynodrel and norethisteron and its acetate and enanthate because these human progestins act predominantly estrogenic in rats. Daily s.c. doses of ethinylestradiol (0.5 mg/kg) produced a rapid increase of liver mass, DNA, RNA, and protein which was almost maximal after 7 days. The percentages of parenchymal cells involved in DNA synthesis and mitosis were enhanced up to 20-fold, suggesting parenchymal hyperplasia as the main cause of liver growth. Sinus wall cells showed a proportionate increase of number and DNA synthesis. Likewise, all other steroids tested produced significant increases of liver mass and DNA. For ethinylestradiol and estradiol extrapolated threshold doses were in the range of 1 microgram/kg. These doses are below those used in previous tumor promotion studies in rats. Using 5 different substrates to check monooxygenase activities of isolated liver microsomes, no induction or only very weak induction by estrogens was found. These studies suggest that induction of liver growth may be a property relevant for the tumor promoting activity of estrogens; in contrast, induction of hepatic monooxygenases does not appear to be necessary for liver tumor promotion in the rat.
Adipose Tissue↗
[The LD50 in comparison with acute toxicity. A critical evaluation of the present method].
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Animals↗
Effect of cyproterone acetate and its metabolites on the adrenal function in man, rhesus monkey and rat.
The effect of oral administration of 17 alpha-acetoxy-6-chloro-1,2 alpha-methylene-4,6]pregnadiene-3,20-dione (cyproterone acetate, Androcur) on the adrenal function in male hypersexual subjects and in female rhesus monkey was investigated on the basis of cortisol and ACTH levels in serum or plasma and excretion of cortisol and 17-ketosteroids. In addition, cyproterone acetate and its main metabolite alcohol of the main metabolite were characterized for treatment of male hypersexual subjects and female rhesus monkeys did not reveal any signs of adrenal suppression. Cyproterone acetate and its metabolites gave on indication of any appreciable anti-inflammatory effect in the adjuvant edema test in rats. However, there was a general increase in the level of blood glucose and liver glycogen as well as a reduction in body weight and organ weight (spleen, thymus and adrenal) in rats, in which 15 beta-hydroxy cyproterone was slightly more active with the exception of adrenal weight tests. It can be concluded that adult man and rhesus monkey are much less sensitive, is so at all, to some corticosteroid-like activities of cyproterone acetate and its main metabolites than the rat.
17-Ketosteroids↗
Characterization of a new potent heparin. 6th communication: The comparison of the anticoagulant effect of the sodium and calcium salts of a new potent heparin after s.c. injection in beagle dogs.
The anticoagulant effect of the sodium and the calcium salts of a new potent heparin was compared in beagle dogs following a single s.c. injection. The determinations of whole-blood clotting time, activated partial thromboplastin time and plasma heparin levels using the amidolytic assay 1, 2, 4, 6, 8, 10 and 12 h post injection revealed that the calcium salt was just slightly more active than the sodium salt of heparin. The influence of the molecular composition in particular the inorganic ion content associated with heparin on the anticoagulation activity achieved after subcutaneous injection, is discussed.
Animals↗