Changes in the concentrations of total RNA and DNA in the cerebral cortex and internal organs (liver and heart) after prolonged hypovolemic hypotension and in the post-resuscitation period

It was shown in experiments on dogs that after 4-hour hypovolemic hypotension the content of total RNA in brain cortex and myocardium homogenates decreased. In the liver, there was a significant decrease both in RNA and DNA content. In the postresuscitation period, the content of nucleic acids in the myocardium returned to normal after 14--21 days, and that in the liver after 3--4 months. The gray matter of the brain manifested a delayed lowering of DNA content (after 14--21 days), and the level of nucleic acid did not return ot normal over 3--4 months after resuscitation.     

The effects of phenylpyruvate and hyperphenylalaninemia on incorporation of (6- 3 H)glucose into macromolecules of slices of rat cerebral cortex

The effects of phenylpyruvate and hyperphenylalaninemia on the incorporation of [6-³H]glucose into lipids, proteins and nucleic acids were examined in differentiating and adult rat brain. Foetal brain was most sensitive to inhibition by phenylpyruvate in vitro, with significant effects occurring at 2·5 mM for labelling of lipids and proteins and at 5 mM for labelling RNA and DNA. Older age groups were less affected, and cortical slices from adult brain were slightly or not at all affected by phenylpyruvate. The inhibition by phenylpyruvate of incorporation of [6-³H]glucose into nucleic acids, proteins, and lipids could be further distinguished by the reversibility of the effect on nucleic acid and protein synthesis at high levels of glucose and the irreversibility of the effect on lipid synthesis. Lipid synthesis was most sensitive to inhibition by phenylpyruvate at the stage of fatty acid synthesis, with lesser effect on the formation of glyceride glycerol. Exposure in utero of the foetal brain to maternal hyperphenylalaninemia resulted in reduction of 26–38 per cent in the subsequent incorporation in vitro of [6-³H]glucose into lipids, proteins, RNA and DNA of brain slices from foetal animals. Feeding hyperphenylalaninemic pregnant rats a high-glucose diet significantly protected the foetal brain from the neurotoxicity accompanying the hyperphenylalanemia.     

Synthesis of nucleic acids in the Schwann cells as the early cellular response to nerve injury

Abstract— The early effect of mechanical injury of the sciatic nerve in cats and rats on the amount of nucleic acids and on the number of Schwann cells was studied. The content of RNA and DNA increased at both ends of a severed nerve as early as 2 hr after operation; at 8 hr and up to 24 hr, their level was about twice as high as at the beginning of experiment. The increase in nucleic acids seemed to be chiefly due to their biosynthesis in the Schwann cells although the possibility of a contribution of axonal RNA must also be taken into consideration. The division of Schwann cell nuclei was observed not earlier than 36 hr after operation. The injury stimulates the synthesis of nucleic acids not only in the Schwann cells directly damaged, but also in those from neighbouring internodes. The increase in DNA and RNA observed 24 hr after a fresh lesion had been made in a degenerating nerve was smaller than the increase observed 24 hr after cutting or crushing a normal nerve.     

CHANGES OCCURRING IN THE CHEMICAL COMPOSITION OF THE CENTRAL NERVOUS SYSTEM DURING FOETAL AND POST-NATAL DEVELOPMENT OF THE SHEEP

(1) The chemical composition of the CNS (separated into cerebrum, cerebellum, brain stem and spinal cord) was determined in sheep during foetal and post-natal development and in adults. (2) The spinal cord differed from the remainder of the CNS in growing more after the period studied (50-day-old foetuses to 5-week-old lambs) than before it. This was largely attributable to lipid accumulation. (3) Chemical growth (accumulation of DNA, protein and lipid) proceeded linearly in spinal cord, logarithmically in cerebrum and cerebellum while in brain stem growth was described by a sigmoid function. (4) Fat-free dry matter, protein, total lipid, cholesterol and phospholipid concentrations increased progressively in all parts of the CNS but DNA concentrations changed little. In the cerebrum alone there was an increase in DNA concentration during maturation suggesting an increased cell population. Cholesterol was present predominantly in the free form but esters were detected in foetal tissues from 70 up to 120 days gestation. (5) Cerebroside, the characteristic lipid of myelin, increased in concentration soon after 85 days of gestation, up to which point very low values were recorded, the rate varying according to the region of the CNS examined. Rates of increase in total regional cerebroside content were used to identify periods of myelination and the results suggest that there are two periods of peak activity, one about 20 days before birth and the other at 10-20 days after birth. (6) The composition of lipids added during the two phases of myelination and during maturation were characteristically different. In the spinal cord, lipid analyses best reflect changes in myelin composition.     

Elevated Monoamine Levels in the Cerebral Hemispheres of Microencephlic Rats Treated Prenatally with Methylazoxymethanol or Cytosine Arabinoside

Abstract: Methylazoxymethanol (MAM) injection to rats on day 15 of gestation caused a significant rise in monoamine concentrations (1.6, 2.0, and 2.8 times the control value for serotonin, norepinephrine, and dopamine, respectively) accompanying a decrease in the brain weight and DNA content in the cerebral hemispheres of the offspring at 3 months of age; in the brain stem, these changes were much smaller. Similar change of monoamine concentrations was observed in cytosine arabinoside-induced microencephaly. The decrease of DNA content and the elevation of monoamine levels were lower with MAM injection on day 15, 13, or 17 of gestation (in that order). Serotonin content of the MAM-treated cerebral hemispheres was already 50% higher than the control immediately after birth. The activity of tryptophan hydroxylase in the MAM-treated cerebrum was 1.6 times the control value, with no change in the brain stem, while the concentration of tryptophan in the brain and plasma was equal to the control value, suggesting an important role played by this enzyme in the elevation of serotonin content. Although the marked decrease of DNA content in the cerebral hemispheres of MAM-treated rats indicates a loss of cerebral cells due to prenatal MAM poisoning, the kind of cells destroyed remain to be studied. That the remaining neurons, axons, and oligodendroglia were intact was suggested by the normal activity of CNPase.     

Effect of denervation on the synthesis of ribonucleic acid and deoxyribonucleic acid in rat diaphragm muscle

1. The effect of unilateral denervation of rat diaphragm muscle on its content of nucleic acids and their incorporation of precursors was investigated. 2. After denervation the paralysed hemidiaphragm hypertrophies and within 3 days its content of RNA increases considerably. The concentration of DNA/unit mass remains fairly constant. 3. During this period there is some increase in the rate of incorporation of [(14)C]adenine into RNA, whereas there is some diminution in the rate of incorporation of [(14)C]orotic acid. 4. Incorporation of [(14)C]adenine and [(3)H]thymidine into DNA is much increased in the paralysed tissue, reaching its maximum by about the third day, but returning to normal by the tenth. 5. The significance of these results in relation to the hypertrophy after denervation is discussed.     

Nitrosamine-induced carcinogenesis. The alkylation of nucleic acids of the rat by N-methyl-N-nitrosourea, dimethylnitrosamine, dimethyl sulphate and methyl methanesulphonate

1. N[(14)C]-Methyl-N-nitrosourea, [(14)C]dimethylnitrosamine, [(14)C]dimethyl sulphate and [(14)C]methyl methanesulphonate were injected into rats, and nucleic acids were isolated from several organs after various time-intervals. Radioactivity was detected in DNA and RNA, partly in major base components and partly as the methylated base, 7-methylguanine. 2. No 7-methylguanine was detected in liver DNA from normal untreated rats. 3. The specific radioactivity of 7-methylguanine isolated from DNA prepared from rats treated with [(14)C]dimethylnitrosamine was virtually the same as that of the dimethylnitrosamine injected. 4. The degree of methylation of RNA and DNA produced in various organs by each compound was determined, and expressed as a percentage of guanine residues converted into 7-methylguanine. With dimethylnitrosamine both nucleic acids were considerably more highly methylated in the liver (RNA, about 1% of guanine residues methylated; DNA, about 0.6% of guanine residues methylated) than in the other organs. Kidney nucleic acids were methylated to about one-tenth of the extent of those in the liver, lung showed slightly lower values and the other organs only very low values. N-Methyl-N-nitrosourea methylated nucleic acids to about the same extent in all the organs studied, the amount being about the same as that in the kidney after treatment with dimethylnitrosamine. In each case the RNA was more highly methylated than the DNA. Methyl methanesulphonate methylated the nucleic acids in several organs to about the same extent as N-methyl-N-nitrosourea, but the DNA was more highly methylated than the RNA. Dimethyl sulphate, even in toxic doses, gave considerably less methylation than N-methyl-N-nitrosourea in all the organs studied, the greatest methylation being in the brain. 5. The rate of removal of 7-methylguanine from DNA of kidneys from rats treated with dimethylnitrosamine was compared with the rate after treatment of rats with methyl methanesulphonate. No striking difference was found. 6. The results are discussed in connexion with the organ distribution of tumours induced by the compounds under study and in relation to the possible importance of alkylation of cellular components for the induction of cancer.     

Effects of methylazoxymethanol given at different stages of postnatal life on development of the rat brain. Comparison with those of thyroid deficiency

Newborn rats were treated at different stages of their development with low doses of methylazoxymethanol acetate. The postnatal increase of the DNA content of the cerebrum did not differ from that of controls. In the cerebellum, the DNA content was transitorily reduced, but later, the external granular layer became thicker and DNA deposition increased in comparison with controls; finally, the cerebellar DNA returned to a normal value. Morphological abnormalities of the cerebellum, abnormal orientation of migrating cells, scattering of Purkinje cell bodies within the internal granule cells and specially striking abnormalities of the morphology and orientation of Purkinje cell dendrites were noted in rats treated with MAM from birth to day 3. The effects on the Purkinje cell morphogenesis persisted but were much less marked when MAM was given from 4 to 7 or from 8 to 11 days. Neonatal thyroid deficiency, as MAM-treatment between days 0 and 3, leads to an abnormal position of Purkinje cell bodies within the cerebellar cortex; it also leads to morphological abnormalities of their dendritic arborization which closely resemble those observed after MAM-treatment during the second postnatal week. It also alters the cell formation in the cerebellum. Thyroid deficiency probably exerts its effect on cell formation earlier than previous biochemical studies have shown. On another hand, the morphological abnormalities of Purkinje cell arborizations in the thyroid-deficient animals may be partly due to the perturbations of cell formation which persist later in the cerebellum.     

Effect of undernutrition on DNA and RNA synthesis in subcellular fractions from different regions of the developing rat brain

The effect of undernutrition on the incorporation of [methyl-³H]thymidine into DNA and of 5-[³H]uridine into RNA of cerebral hemispheres, cerebellum, and brain stem was studied in vivo and in vitro in rats. The labeling of DNA from nuclei and mitochondria and of RNA from nuclei, mitochondria, microsomes, and soluble fractions, was also measured in vitro. The results demonstrate that nucleic acid synthesis is impaired and delayed during undernutrition. Specific effects were observed for the different brain regions and subcellular fractions: at 10 days nuclear and mitochondrial DNA and RNA synthesis was impaired, whereas at 30 days only the mitochondrial nucleic acid synthesis was affected.The delay of DNA and RNA labeling, caused by undernutrition, was most evident in the cerebellum, probably due to its intense cell proliferation during postnatal development. The specific sensitivity of mitochondria as compared to other subcellular fractions, may be due to the intense biogenesis and/or turnover of nucleic acids in brain mitochondria not only during postnatal development, but also in the adult animal.     

Animal models of brain maldevelopment induced by cycad plant genotoxins

Cycads are long‐lived tropical and subtropical plants that contain azoxyglycosides (e.g., cycasin, macrozamin) and neurotoxic amino acids (notably β‐N‐methylamino‐l ‐alanine l ‐BMAA), toxins that have been implicated in the etiology of a disappearing neurodegenerative disease, amyotrophic lateral sclerosis and parkinsonism‐dementia complex that has been present in high incidence among three genetically distinct populations in the western Pacific. The neuropathology of amyotrophic lateral sclerosis/parkinsonism‐dementia complex includes features suggestive of brain maldevelopment, an experimentally proven property of cycasin attributable to the genotoxic action of its aglycone methylazoxymethanol (MAM). This property of MAM has been exploited by neurobiologists as a tool to study perturbations of brain development. Depending on the neurodevelopmental stage, MAM can induce features in laboratory animals that model certain characteristics of epilepsy, schizophrenia, or ataxia. Studies in DNA repair‐deficient mice show that MAM perturbs brain development through a DNA damage‐mediated mechanism. The brain DNA lesions produced by systemic MAM appear to modulate the expression of genes that regulate neurodevelopment and contribute to neurodegeneration. Epigenetic changes (histone lysine methylation) have also been detected in the underdeveloped brain after MAM administration. The DNA damage and epigenetic changes produced by MAM and, perhaps by chemically related substances (e.g., nitrosamines, nitrosoureas, hydrazines), might be an important mechanism by which early‐life exposure to genotoxicants can induce long‐term brain dysfunction. Birth Defects Research (Part C) 99:247–255, 2013. © 2013 Wiley Periodicals, Inc.     

The uptake of [3H]uridine into the nucleic acids of rat uterus during early pregnancy

1. Changes in content and uptake of [(3)H]uridine into the nucleic acids of rat uterus during the first 9 days of pregnancy were studied. 2. From day 6 implantation sites were separated from the rest of the uterine tissue for independent analysis. 3. Up to day 5 of pregnancy no changes were found in the total dry matter or in RNA and DNA content/unit dry matter nor in the RNA/DNA ratios. 4. From day 6, when implantation sites are visible, the water content of the implantation sites increased by 2-3%, and the RNA content/unit dry wt. and the RNA/DNA ratios increased. The DNA content/unit dry wt. did not increase in the implantation sites until day 8. 5. Uptake of [(3)H]uridine into the acid-soluble fraction of the tissues was markedly higher in implantation sites than in non-implantation sites. 6. Uptake of [(3)H]uridine into RNA was significantly increased on day 3 of pregnancy and again on day 5. 7. On days 6 and 7, the incorporation into RNA of implantation sites was significantly higher than in the remainder of the uterine tissue but decreased on days 8 and 9 to the same value as that of the normal tissue. 8. No change occurred in uptake into DNA until day 6, when there was an increase in uptake by the implantation sites. 9. It is suggested that the increase in RNA synthesis on day 3 is a preparation of the uterus for the onset of implantation on day 5, and that increased synthesis in implantation sites on days 6 and 7 is the elaboration of new RNA necessary for this early stage of pregnancy to commence.     

The effect of feeding 11-ketotestosterone on the food conversion efficiency and tissue protein and nucleic acid contents of juvenile carp, Cyprinus carpio L.

Juvenile common carp were fed 11-ketotestosterone for 60 days with the diet and the effect on food conversion efficiency, organ weights and protein and nucleic acids (RNA, DNA) content of the liver, kidney, brain and muscle were observed. Feeding of the steroid increased the food conversion efficiency of all the experimental groups studied as compared with controls. A decrease in weight of brain, liver and kidney in relation to body weight was noticed after 60 days of the hormone feeding. No change in the visceral weight was observed. These changes in relative weights of the organ were ameliorated 30 days after the withdrawal of the steroid from the food. The weight of the viscera decreased compared with the control weight during this time. Feeding of the hormone brought variable changes in the total proteins, RNA/DNA, protein/RNA and protein/DNA in all the organs studied. In addition to these findings, changes in the moisture, total lipid and ash contents of the muscle were also observed. The results are discussed in the light of existing knowledge of the effect of anabolic-androgenic steroids on the growth processes of different organisms.     

A COMPARATIVE STUDY OF THE METABOLISM OF DE NOVO SYNTHESIZED FATTY ACIDS FROM ACETATE AND GLUCOSE, AND EXOGENOUS FATTY ACIDS, IN SLICES OF RABBIT CEREBRAL CORTEX DURING DEVELOPMENT

Slices of rabbit cerebral cortex, from the foetal stage to the adult have been used to compare lipid synthesis from fatty acids synthesized de novo from [U-¹⁴C]glucose and [1-¹⁴C]acetate, with lipid synthesis from exogenous albumin-bound [1-¹⁴C]palmitate. Incorporation into cellular lipid has been determined in terms of DNA, protein, wet wt. of tissue and wet weight of whole brain. On a wet wt. basis, maximum incorporation of glucose carbon into lipid occurred in the foetal brain while lipid synthesis from acetate and palmitate was maximum at 4–14 days after birth. Glucose and acetate were incorporated into a diversity of lipids (with increasing amounts of phosphatidylcholine synthesized during maturation), while palmitate was incorporated into the free fatty acid and triglyceride fractions. A greater proportion of acetate was incorporated into fatty acids of chain-length longer than C16 compared with the incorporation of palmitate. However, on a molar basis de novo synthesized and exogenous palmitate were elongated, desaturated and incorporated into phospholipids at a similar rate, while exogenous palmitate was incorporated to a greater extent than de nova synthesized fatty acid into the triglyceride fraction. This difference in metabolism may be due to the different size of the non-esterified fatty acid pool in the two situations. At the period of their most active formation, the very long-chain fatty acids may be synthesized from a pool of the C18 series of fatty acids (saturated and monoenoic) not in equilibrium with the bulk of C₁₈ acids in cerebral lipids. This could be a pool of acyl groups derived from ethanolamine phospholipids.     

Stimulation of mouse lymphocytes by a mitogen derived from Mycoplasma arthritidis. V. A small basic protein from culture supernatants is a potent T cell mitogen

Previous studies established that Mycoplasma arthritidis produces a soluble T cell mitogen (MAM), and that response of murine T cells to MAM is genetically restricted. MAM appeared predominantly in the supernatants of senescent cultures, but was not extracted in significant amounts from whole cells. A quantitative assay of MAM activity was devised. MAM formed noncovalent complexes with nucleic acids and uncharacterized high m.w. constituents of sera and of complex media. Partially purified MAM was adsorbed or denatured by glass and plastic surfaces. MAM was protease-labile, had pI greater than or equal to 9, and had Mr ca 15,000 according to gel filtration experiments. MAM was a very minor component of culture supernatant proteins, and even after 200- to estimated 5 X 10(4)-fold purification was not identified as a stainable or ultraviolet-absorbing entity in electrophoretigrams or chromatograms. It was estimated that MAM was half-optimally active at less than 1000th the half-optimal concentration of concanavalin A or phytohemagglutinin. Culture supernatants and highly purified MAM exhibited the same haplotype specificity (H-2k-dependent response) for stimulated proliferation of lymphocytes and for induction of interferon in vitro.     

A cellular gene encodes scrapie PrP 27-30 protein

A clone encoding PrP 27-30, the major protein in purified preparations of scrapie agent, was selected from a scrapie-infected hamster brain cDNA library by oligonucleotide probes corresponding to the N terminus of the protein. Southern blotting with PrP cDNA revealed a single gene with the same restriction patterns in normal and scrapie-infected brain DNA. A single PrP-related gene was also detected in murine and human DNA. PrP-related mRNA was found at similar levels in normal and scrapie-infected hamster brain, as well as in many other normal tissues. Using antisera against PrP 27-30, a PrP-related protein was detected in crude extracts of infected brain and to a lesser extent in extracts of normal brain. Proteinase K digestion yielded PrP 27-30 in infected brain extract, but completely degraded the PrP-related protein in normal brain extract. No PrP-related nucleic acids were found in purified preparations of scrapie prions, indicating that PrP 27-30 is not encoded by a nucleic acid carried within the infectious particles.     

Characterization of nucleic acids in membrane vesicles from scrapie-infected hamster brain.

This study reports the partial characterization of nucleic acids present in gradient fractions enriched for large membrane vesicles from scrapie-infected and uninfected hamster brains. Labeling of phenol-extracted nucleic acids at the 3' or 5' ends revealed abundant amounts of low-molecular-weight RNA and little or no DNA. These nucleic acids survived nuclease treatment of membrane vesicles but were sensitive to RNase after phenol extraction. Analysis of 5'-end-labeled nucleic acids by one- and two-dimensional gel electrophoresis revealed an RNA of ca. 100 bases in preparations from scrapie-infected hamster brain that could not be detected in uninfected brain. The possibility that this apparently unique small RNA may result from tissue damage or abnormal RNA processing or may be a component of the infectious complex is discussed.     

Characterization and metabolism of ovine foetal lipids

1. Total phospholipid concentrations in liver, kidney and brain of the 140-day ovine foetus were only half of those in comparable maternal tissues. 2. Phosphatidylcholine was the predominant phospholipid in all foetal tissues examined. The most striking difference between foetal and maternal tissues in individual phospholipids was in the heart; foetal heart contained more ethanolamine plasmalogen than choline plasmalogen, whereas in adult tissue the concentration of these was reversed. Sphingomyelin content of foetal brain was only one-sixth of that of maternal brain tissue. 3. Oleic acid (18:1) was the predominant acid in the phospholipid extracted from foetal tissues, except in brain where palmitic acid (16:0) was slightly higher. In phospholipids from adult tissues there was a higher proportion of unsaturated fatty acids (linoleic acid, 18:2, and linolenic acid, 18:3) and a correspondingly lower proportion of oleic acid (18:1). The distribution of fatty acids in the neutral lipid fraction of foetal and maternal tissues was very similar; oleic acid (18:1) was generally the principal component. 4. (14)C derived from [U-(14)C]-glucose and [U-(14)C]fructose infused into the foetal circulation in utero was incorporated into the neutral lipids and phospholipids of heart, liver, kidney, brain and adipose tissue. 5. Phospholipid analysis revealed that the specific activity of phosphatidic acid was higher in liver than in other tissues. The specific activity of phosphatidylethanolamine was less than that of phosphatidylcholine in heart, but in other tissues they were about the same. The specific activities of phosphatidylinositol and phosphatidic acid in brain were very similar and were higher than the other components. The specific activity of phosphatidylserine was highest in liver and brown fat. 6. The pattern of incorporation of (14)C derived from [(14)C]glucose and [(14)C]fructose into foetal neutral lipids was similar. Diglyceride accounted for most of the radioactivity in brain, whereas triglyceride had more label in heart, liver, kidney and fat.     

In vivo alkylation of foetal, maternal and normal rat tissue nucleic acids by 3-methyl-1-phenyltriazene.

The carcinogen 3-methyl-1-phenyltriazene (MPT) was administered subcutaneously to normal or pregnant BD VI rats and DNA and RNA were isolated from various tissues after 8 h or 15 h, respectively. Sephadex G-10 chromatography of DNA hydrolysates showed the presence of 7-methylguanine in all tissues examined including that of the brain, one of the target organs for tumour induction. The amounts of the minor product, O6-methylguanine, were characteristic of an SN1 reaction mechanism. Dowex-50 chromatography of RNA hydrolysates showed the presence of 7-methylguanine and of the minor product, 3-methylcytosine. The relative amounts, both of the methylated bases in the individual nucleic acids and of 7-methylguanine in DNA and RNA, were similar to those found previously after administration of 3,3-dimethyl-1-phenyltriazene (DMPT). This suggests the involvment of a common alkylating intermediate. De novo incorporation of radioactivity into purine bases was detected in both DNA and RNA although the levels were not related to the amounts of methylation. The results show that MPT is sufficiently stable to alkylate nucleic acids in vivo and are consistent with the hypothesis that this reaction is a prerequisite for tumour induction. Futhermore, they support the proposal that MPT is the active intermediate in the induction of tumours by DMPT.     

Brain nucleic acids and protein in various neurological mutant mice

A study was made to compare alterations in the cerebral contents of nucleic acids and protein of several mouse strains affected by different neurological mutations: jimpy, msd, quaking, reeler, weaver, and dwarf. In normal and affected jimpy and msd mice the brain components analyzed were very similar. On the other hand, the cerebral hemispheres of quaking mice showed significant decreases in total RNA and DNA, when compared with those of normal littermates. In the affected reeler and weaver mice, total protein, RNA, and DNA in the cerebellum differed markedly from controls. Protein decreased slightly, whereas nucleic acids showed no significant variation in the cerebral hemispheres of the same mutants. The cerebella and cerebral hemispheres of affected dwarf mice had wet weights and total protein contents that were about 20% lower than those of their controls; DNA did not vary significantly in the various brain regions analyzed. The decrease of DNA we report in reeler and weaver mutant cerebellum in toto quantifies the lack of cell number, in contrast to histological studies which give only semiquantitative information.     

Brain changes in rats induced by prenatal injection of methylazoxymethanol

Various doses (0, 1, 5, 10, 15, 20, or 25 mg/kg) of methylazoxymethanol acetate (MAM), a potent alkylating agent, were injected singly into pregnant rats intraperitoneally on day 15 of gestation. Relationships between brain weights and neurochemical changes in the cerebral hemispheres (CHs; cerebral cortex and subjacent white matter, hippocampus, amygdala) and remainder of the brain (BGDM; basal ganglia, diencephalon, and mesencephalon) were examined at 60 days of age in offspring; varying degrees of microencephaly were observed. Dose-dependent reductions in the weights of CH and BGDM were observed. Reductions in total DNA content positively correlated with decreases in brain weights also observed. Dose-dependent elevations of noradrenaline (NA) and dopamine (DA) were observed in CH at MAM levels 10 mg/kg and above; dose-dependent elevations of 5-hydroxytryptamine (5-HT) were observed at 15 mg/kg and above; and in BGDM at 20 mg/kg and above dose-dependent elevations for NA and 5-HT were observed; dose-dependent elevations at 15 mg/kg and above were observed for DA. Monoamine concentrations were negatively correlated with brain weights or total DNA contents. NA and DA concentrations increased to the extent of approximately 1.3 times of control at a time when an 18% loss of CH weight was noted in animals treated with 10 mg/kg MAM. It is suggested that the above variables might be appropriately sensitive neurochemical markers for detecting minor developmental anomalies in the brain.