Purification of a candidate gonadotrophin surge attenuating factor from human follicular fluid

Gonadotrophin surge attenuating factor (GnSAF) is a new non-steroidal ovarian substance, different from inhibin, which attenuates the pre-ovulatory luteinizing hormone (LH) surge in superovulated women. Human follicular fluid (FF) was used as a source for the isolation of GnSAF, the activity of which was monitored in an in-vitro pituitary bioassay. Primary rat pituitary cells were incubated with test substances for 48 h and subsequently washed and incubated with 0.1 micromol/l gonadotrophin releasing hormone (GnRH) plus test substances for 4 h. GnSAF activity was expressed as the reduction of GnRH-induced LH secretion in the 4 h incubation. GnSAF was purified from 250 ml of FF which was heat-treated at 80 degrees C for 5 min. Heparin-sepharose chromatography, Con-A sepharose chromatography, reversed-phase high-performance liquid chromatography (HPLC) and preparative native gel electrophoresis were used for GnSAF fractionation. Using these purification steps, we have obtained an apparently homogeneous preparation that stains as a single band on sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. GnSAF has an apparent molecular weight of 12.5 kDa and was identified by amino acid sequence (mass spectrometry) to be the C-terminal fragment of human serum albumin.

Development and application of competitive ELISA assays for rat LH and FSH

Rat LH (rLH) and FSH (rFSH) were measured by sensitive and specific competition ELISAs. The rat LH ELISA used rLH-I-9 coated plates, an antiserum against rLH and an antibody against rabbit IgG labeled with peroxidase. Using rLH-RP-3 as a standard, rat LH was determined by binding of the anti-LH antibody to rLH-I-9 coated plates. The sensitivity of the assay was 0.8 ng/mL. Similarly, the rat FSH-ELISA used rFSH-I-8 coated plates, an antiserum against rFSH and an antibody against rabbit IgG labeled with peroxidase. Using rFSH-RP-3 as a standard, the FSH-ELISA was also determined by binding of the anti-FSH antibody to rFSH-I-8 coated plates. The sensitivity of this assay was 1.25 ng/mL. Both rat LH and FSH ELISA assays are highly specific and provide accurate determination of gonadotrophins in buffers, sera, cell culture media, and anterior pituitary extracts. These assays were used for monitoring the gonadotrophin surge-attenuating factor (GnSAF) and inhibin activities present in human follicular fluid (hFF). The 2 new ELISA procedures have practical advantages (safety, convenience, economy) over the RIA methods, and they perform as well as the RIA techniques at the same range of concentrations.

The effect of sclareol on growth and cell cycle progression of human leukemic cell lines

Sclareol, a labdane-type diterpene, was tested for cytotoxic effect against a panel of established human leukemic cell lines. The compound showed an IC50 lower than 20 microg/ml in most cell lines tested, while it was higher for resting peripheral blood mononuclear leukocytes (PBML). Furthermore, the compound was tested for cytostatic activity against four of the leukemic cell lines used. At a concentration of 20 microg/ml the compound showed a significant cytostatic effect as soon as 4 h after continuous incubation against two from B and two from T lineage cell lines. The morphology and the kind of death induced from sclareol in three cell lines, was also investigated. The effect of sclareol on the cell cycle progression of two cell lines, using flow cytometry, was examined. The results show that sclareol kills cell lines, through the process of apoptosis. The appearance of the apoptotic signs is time and dose dependent. From the flow cytometry experiments, a delay of the cell population on G0/1 seems to take place. This is the first report, that a labdane type diterpene kills tumor cells via a phase specific mechanism which induces apoptosis.

D-amphetamine, cocaine and caffeine: a comparative study of acute effects on locomotor activity and behavioural patterns in rats

Although open-field behaviour has been considered a valid and reliable index of locomotor activity in rodents, the simple measures traditionally recorded in this test do not readily allow for differentiation between compounds of the same general class, e.g. psychostimulants. The present methodology was developed to facilitate detailed and continuous observations on the behaviour of drug-treated rats. In addition to an automated (photocell) measure of general locomotor activity, ethological techniques were used to record the frequency and duration of standing, moving, sniffing, rearing, grooming, scratching, sniffing air, freezing, head-swinging and licking. A series of factor analyses was also performed in order to further characterize treatment-induced changes in the structure of behaviour. Compounds studied were d-amphetamine (0.5, 1.5, 3, 6 mg/kg), cocaine (5, 10, 20, 50 mg/kg) and caffeine (5, 10, 20, 40 mg/kg). Although all three psychostimulants increased the automated measure of general locomotor activity, cocaine (which produced the largest effects) monotonically increased general activity over the dose range tested, whereas the stimulant effects of the other two compounds were either reduced (d-amphetamine) or eliminated (caffeine) at higher doses. More detailed observations provided confirmation of the differences in effect produced by these compounds. For example, the frequency and duration of 'moving' dose-dependently increased after cocaine, while d-amphetamine and caffeine again produced bell-shaped dose-response curves. However, whereas low-intermediate doses of d-amphetamine reduced the mean duration of moving, sniffing and rearing, no such effect was observed at the highest dose tested. This finding, together with the appearance of licking in the behavioural repertoire, suggests a stereotyped character to responses seen at high doses of this compound, though neither cocaine nor caffeine induced stereotypy. As factor analyses also revealed quite different behavioural structures associated with these three drugs, present findings demonstrate that detailed observation of behaviour represents a useful approach to research on the behavioural pharmacology of psychostimulants.

Alterations in central monoaminergic neurotransmission induced by polycyclic aromatic hydrocarbons in rats

Benzo[alpha]pyrene (B[a]P) is a product derived from incomplete combustion of organic material and is considered responsible for chemically-induced cancer in humans. In the present study, the levels of noradrenaline (NA), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in the brains of female Wistar rats 6, 12, 24 and 96 h after a single dose of B[alpha]P (50 mg kg(-1) b.w., i.p.), and also after repeated administration of B[alpha]P (50 mg kg(-1) b.w., i.p., 2 x wk, 1 mo). The brain regions studied were the striatum, hypothalamus, midbrain and cortex. Catecholamines were measured using high performance liquid chromatography (HPLC) and electrochemical detection. Significant changes were observed in the striatum where NA, DA, DOPAC were decreased after 24 h and HVA was decreased after 6 h. In contrast, no major alterations occurred in 5-HT and 5- HIAA. In the hypothalamus, a significant decrease in NA was observed after 96 h. In the midbrain, the most important change observed was the decrease in NA after 24 h. A trend toward an increase in 5-HIAA was observed in the cortex after 6 h. The results demonstrate that B[alpha]P induces alterations in the dopaminergic and serotoninergic systems throughout the brain. These alterations may lead to behavioural and hormonal disturbances.

Evidence of alpha2-adrenoceptor involvement in B[alpha]P induction processes of drug-metabolizing enzymes: the effect of stress

Central to the appropriate regulation of behavioral and physiological changes induced by stress are the noradrenergic neuronal systems which have been implicated in a large number of stress-induced pathophysiological states. Endoplasmic reticulum-bound cytochromes (CYPs) play a crucial role in drug metabolism, resulting in deactivation or formation of reactive derivatives. In turn, these products may be responsible for the chemotherapeutic, mutagenic or carcinogenic properties of the parent compound. The present study assesses the effect of a specific alpha2- adrenoceptor agonist, dexmedetomidine (DEXT), on stress-induced modification of cytochrome activity in rats using a restraint stress model. The results indicated that activation of the alpha2-adrenoceptor with DEXT did not alter basal hepatic methoxyresorufin 7-dealkylase (MROD). On the other hand, it appeared to enhance MROD in benzo[alpha]pyrene (B[alpha]P) treated animals. Of interest was the finding that stress blocked DEXT-induced MROD enhancement in B[alpha]P- treated rats. In addition, DEXT had no effect on basal hepatic pentoxyresorufin 7-dealkylase (PROD), while it further enhanced the strong induction by B[alpha]P. Stress was also found to block this effect. Hepatic ethoxyresorufin 7-dealkylase (EROD) activity was strongly increased by B[alpha]P; this effect was enhanced by DEXT. In contrast, the DEXT enhanced induction was further strengthened by stress. These findings suggest that alpha2-adrenoceptors may modulate the induction of cytochromes CYP1A1, 1A2 and 2B1 by B[alpha]P in rats and that stress may modify this process. In particular, stress may regulate the inducibility of P4501A1 activity by B[alpha]P via mechanisms related to alpha2-adrenoceptors.

The role of stress in the regulation of drug metabolizing enzymes in mice

The role of stress in the regulation of several enzymatic systems which are involved in the biotransformation of xenobiotics in the liver was investigated in this study using restraint stress as a stress model. The results demonstrated that stress suppressed total basal P450 content (35%) and basal ethoxyresorufin 7-dealkylase (EROD) activity (33%), while slightly increasing basal methoxyresorufin 7-dealkylase (MROD) activity (20%). Basal pentoxyresorufin 7- dealkylase (PROD) and coumarin 7-hydroxylase (COH) activities were not affected. On the other hand, restraint stress increased total P450 content in 1,4-bis[2-(3,5- dichloropyridyloxy)]benzene (TCPOBOP)-treated mice (35%), while slightly suppressing PROD activity (26%). In addition, CYP2E1 dependent p-nitrophenol hydroxylation (PNP), was suppressed (40%) by stress in TCPOBOP-treated animals and cytosolic aldehyde dehydrogenases were not affected. Although stress had no effect on basal P4502A5 activity, the inducibility of this hepatic activity increased 2-fold after stress exposure. A pronounced suppression (7-fold) in glutathione content was observed in lungs of TCPOBOP treated mice after stress, whereas basal levels remained unaffected. In addition, only a slight suppression (20%) in liver glutathione content was found in both treatment groups. Northern blot analysis revealed that restraint stress had a relatively suppressive effect on control CYP1A2 expression in the liver. In contrast, stress markedly enhanced the expression of liver CYP2A5 in TCPOBOP-treated mice, but did so to a lesser extent in controls. Stress also increased CYP2A5 mRNA in TCPOBOP-treated mice to a greater degree than the activity of the corresponding cytochrome. On the other hand, liver P4502A5 activity was found to be induced by TCPOBOP by about 2.5-fold. However, the drug does not appear to be involved in the expression of CYP2A5. Finally, although the activity of liver P4502A5 cytochrome was found to be increased 3, 8 and 27 h after stress, after which it gradually declined up to 75 h, CYP2A5 liver expression appeared to be suppressed 3, 8, 27 and 51 h after stress, while 75 h later it apparently reached normal levels. In conclusion, the results of this study showed that restraint stress significantly alters several enzymatic systems differently at a basal level than under conditions of TCPOBOP induction. In addition, stress was found to significantly interfere with the expression processes of CYP1A2 and CYP2A5.

Anti-inflammatory agents and inducibility of hepatic drug metabolism

Two rat liver cytosolic aldehyde dehydrogenases, ALDH1 and ALDH3c, are of particular interest because they are inducible by different classes of xenobiotics. ALDHI is mainly increased by phenobarbital-type inducers; polycyclic aromatic hydrocarbons (PAHs), such as 3- methylcholanthrene (3MC), increase ALDH3c enzyme activity in all rat species currently tested. In addition, ALDH3c has been found to reflect the subfamily CYPIA of cytochrome P-450, as well as other enzymes functionally related to the aryl hydrocarbon receptor (the "Ah-receptor enzyme battery"), which is activated by the same type of inducers. In the present study we investigated whether the induction of ALDH3c might be connected with a chemically produced aseptic inflammation of the hepatocyte. To answer this question, we examined the relationship between the induction of ALDH3c by 3MC and the arachidonic acid cascade. Different non-steroid anti-inflammatory drugs (NSAIDs) were tested in combination with 3MC and in post-treatment. The 3MC-induced ALDH3c activity was significantly diminished by the co-administered anti-inflammatory agents. Two microsomal enzyme activities (ethoxyresorufin-O-deethylase, EROD; aryl-hydrocarbon-hydroxylase, AHH) were also decreased. Similar results were obtained with NSAIDs administered to animals pre- treated with 3MC, as far as the ALDH3c activity was concerned, but not for the microsomal enzyme activity (EROD and AHH). In conclusion, the induction of ALDH3c, after PAH treatment, may be related to an aseptic inflammation of the hepatocytes. This effect is reduced by commonly used steroid and non-steroid anti- inflammatory drugs, and although the mechanism of inhibition has not yet been elucidated, it appears likely that ALDH3c and CYP1A activities are associated with the "acute phase" response.

Zoxazolamine-induced paralysis in two rat substrains: differences in hepatic drug metabolism

Aldehyde dehydrogenase (ALDH) is involved in the metabolism of endogenous and exogenous aldehydes originating from biogenic amines, lipids, food and drugs. Rat liver contains at least two cytosolic ALDHs that can be stimulated by inducers of drug metabolism. Phenobarbital- type inducers increase ALDH1 activity while polycyclic aromatic hydrocarbons (such as benzo[alpha]pyrene) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increase ALDH3c isoenzyme activity. Two rat substrains were isolated according to a different induction of hepatic ALDH after treatment with phenobarbital (PB). Animals that responded to treatment (RR) and those that did not respond (rr) were inbred and divided into two homogenous groups. These animals constituted an ideal experimental model due to their common origin. Apart from the dramatic induction of cytosolic ALDH1 and ALDH3c, the effects of PB on pentoxy-, ethoxy- and methoxy-resorufin-O-dealkylase (P-, E-, and MROD) between the two substrains were also studied. 3-Methylcholanthrene (3MC) greatly increased ALDH3c levels in both substrains, although it was slightly more pronounced in the rr rats, in which it was assessed either as ALDH3c or as total cytosolic ALDH. A similar trend was also noted in EROD, PROD and MROD activities. Dealkylation of the methoxy group was found to be statistically different between the two substrains (rr > RR). The relevance of the biochemical findings with the in vivo hepatic capacity for drug metabolism was investigated by measuring the duration of zoxazolamine paralysis. Both animal substrains were tested with zoxazolamine either without pretreatment or after administration of PB or 3MC: the paralysis produced by zoxazolamine lasted for a longer period in rr than in RR rats. After pretreatment with PB, the duration of paralysis was greatly reduced, but the differences between the two substrains remained. Pretreatment with various doses of 3MC produced differences in the duration of paralysis in RR and rr rats, although the time period was much shorter than that observed in control animals.

Suppression of the acquisition of conditioned avoidance behavior in the rat by 3-methylcholanthrene

Repeated treatment with 3-methylcholanthrene (MC; 25 mg/kg body weight, i.p., two times per week, 1 month) in both male and female Wistar rats resulted in decreased performance in two sessions of a two-way active avoidance procedure. In addition, young male rats that were injected repeatedly with MC prepubertally showed diminished acquisition in conditioned avoidance behavior during both sessions. It appears that MC can alter both avoidance acquisition and retention test performance in adult male and female rats, as well as in young males. This effect was not associated with alterations in sex hormone levels. The findings of this study suggest a significant influence of MC on specific mental functions.

Modification of reproductive function in the rat by 3-methylcholanthrene

Repeated exposure of adult female Wistar rats to 3-methylcholanthrene (MC) (25 mg kg(-1) b.w., i.p., 2xwk, 1 mo) was associated with a significant increase in estrus cycle length. In addition, an increased frequency of females with constant diestrus and abnormal cycles was observed. Young females which had been exposed to MC prepubertally or whose parents had been treated with MC before and during mating also demonstrated cycle prolongation and an increased incidence of constant diestrus and abnormal cycles. These changes in female reproductive function were not associated with measurable changes in plasma sex hormone levels. In contrast, MC exposure in adult males was associated with significant reductions in circulating plasma testosterone levels. The present data also suggest that the offspring of parents who had been exposed repeatedly to MC before and during mating are also affected. Although the central nervous system in offspring of MC-treated parents appeared to be intact, their oral body temperature was significantly lower.

Ligands of four receptors in the nuclear steroid/thyroid hormone superfamily inhibit induction of rat cytosolic aldehyde dehydrogenase-3 (ALDH3c) by 3-methylcholanthrene

Using six ligands that bind to four different receptors in the nuclear steroid/thyroid hormone superfamily, we have examined the effects of these chemicals on induction of the cytosolic aldehyde dehydrogenase (ALDH3c) activity by 3-methylcholanthrene (3MC) in rat liver and uterus. In contrast to negligible activities in the untreated rat, ALDH3c enzyme activities are induced after a single dose of 3MC. Hepatic ALDH3c induction is decreased 60% to 90% when 3MC is administered together with any of the following ligands: estradiol, testosterone, progesterone, hydrocortisol, diethylstilbestrol, or tamoxifen. None of these same doses of chemicals, administered alone, affects ALDH3c enzyme activity. In addition, when these ligands are injected 2 days after 3MC, no changes are observed in liver or uterus ALDH3c induction. These results suggest that ligands that bind to different receptors in the nuclear steroid/thyroid hormone superfamily might inhibit the ALD3H3c induction process by polycyclic aromatic hydrocarbons; the molecular mechanism(s) of this inhibitory effect is not yet understood.

Lack of response of the rat liver "class 3" cytosolic aldehyde dehydrogenase to toxic chemicals, glutathione depletion, and other forms of stress

One of the rat liver "Class 3" cytosolic aldehyde dehydrogenases (EC 1.2.1.3), ALDH3c, is known to be markedly induced by polycyclic aromatic hydrocarbons and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin). In the present study we examined whether hepatic ALDH3c induction is a general response to toxicity. Treatment of Wistar rats for 4 days with known toxic doses of hepatotoxic agents--carbon tetrachloride, dimethylnitrosamine, diethylnitrosamine, aflatoxin B1, and D-ethionine--did not induce ALDH3c enzyme activity. Whereas dimethylaminoazobenzene at 100 mg/kg/day for 4 days did not increase ALDH3c, a 10-fold lower dose of dimethylaminoazobenzene for 4 days produced a 20-fold increase in ALDH3c activity. Treatment with phorone, diethylmaleate or L-buthionine-S,R-sulfoximine--which deplete reduced glutathione (GSH) by different mechanisms--did not affect ALDH3c activity. One dose of benzo[a]pyrene for 24 hr increased ALDH3c activity by 25-fold. Treatment with both the GSH-depleting chemicals and benzo[a]pyrene inhibited ALDH3c induction by 45% to 75%, suggesting a role for GSH during ALDH3c induction. After ALDH3c activity had already been induced by benzo[a]pyrene, however, the GSH-depleting chemicals did not affect ALDH3c activity. No changes in ALDH3c activity were seen 24 or 48 hr after partial hepatectomy, on the fifth day following surgical cholestasis, or after guanethidine-induced sympathectomy. These data indicate that hepatic ALDH3c inducibility in the rat is not a general or direct response to chemical toxicity, or to conditions of GSH depletion or other forms of stress.

Diethylstilboestrol: II, pharmacology, toxicology and carcinogenicity in experimental animals

Diethylstilboestrol (DES) exerts several toxic effects in experimental animals, by mechanisms which are still unclear. The genotoxicity of the drug has been attributed to a quinone metabolite and is mainly clastogenic, including sister chromatid exchange, unscheduled DNA synthesis, chromosomal aberrations, disruption of mitotic spindle and aneuploidy. There is evidence that genotoxic effects may occur also transplacentally. Intrauterine and early postnatal exposure to DES can cause a variety of dysplasias. In the offspring of female mice exposed to DES during pregnancy, histological changes are observed in the vaginal and cervical epithelium, the endometrium, the ovary, the testis and the epididymis. Prenatal exposure of rats to DES led to decreased litter size and to urethrovaginal cloaca, penile and testicular hypoplasia, and cryptorchidism. Vaginal ridging, vaginal adenosis, testicular hypoplasia and cryptorchidism have been observed in rhesus monkeys following prenatal exposure. There is sufficient evidence that diethylstilboestrol is carcinogenic in experimental animals, after either prenatal or postnatal exposure. Mice show a similar type of carcinogenicity to that observed in humans, target organs being vagina, cervix, uterus, ovary, mammary gland and testis. In rats, prenatal exposure to DES produces mostly mammary and pituitary tumours, but also some tumours of the vagina. Hamsters develop tumours of vagina, cervix, endometrium, epididymis, testis, liver and kidney. DES induces ovarian papillary carcinomas in dogs, and malignant uterine mesotheliomas in squirrel monkeys. Some experimental evidence points to the possibility of a transgenerational carcinogenic effect, since prenatal treatment of mice with DES is followed by an increased incidence of uterine and ovarian carcinomas in the second-generation descendants. Experimental results could have been used to predict the adverse effects of DES observed in humans in the early 1970s: DES had been reported to be carcinogenic in mice in the 1930s, while experiments in the 1960s had provided evidence that exposure during pregnancy could result in an increased cancer risk in the progeny.

Diethylstilboestrol: I, Pharmacology, Toxicology and carcinogenicity in humans

Diethylstilboestrol is still used as an adjunct palliative treatment in certain patients with breast and prostate cancer. Its pharmacological, toxicological and carcinogenic properties are reviewed. In addition to the usual untoward effects following subacute or chronic administration of oestrogens, treatment with diethylstilboestrol has been associated with serious cardiovascular sequelae. Most characteristic are, however, the carcinogenic properties of this drug. Many epidemiological data provide evidence that prenatal exposure to diethylstilboestrol is causally associated with vaginal and cervical clear-cell adenocarcinomas, a very rare type of cancer in the unexposed female population. The intrauterine exposure of males leads to an increased risk of testicular cancer, although the data are less conclusive in this respect. There is some evidence that administration of diethylstilboestrol in large doses to adult women during pregnancy increases the risk of subsequent breast cancer and it probably increases the incidence of endometrial carcinoma, as has been shown with other similar oestrogens given chronically for menopausal symptoms.

Carcinogenic properties of pharmaceutical agents evaluated in the IARC Monographs programme

Almost 200 pharmaceutical chemicals and groups of drugs have been evaluated for their carcinogenic properties by working groups convened by the International Agency for the Research on Cancer. Therapeutic agents are exceptional environmental carcinogens in that humans are exposed to relatively pure substances at well-defined dosages. Of those evaluated, 20 are conclusively carcinogenic to humans and 52 are probably or possibly carcinogenic. The human tissues most often affected are bone marrow, skin, urinary bladder, liver, lymphatic tissue and endometrium. In cases in which there is sufficient evidence for carcinogenicity from both epidemiological and experimental studies, the similarity between humans and animals with regard to the target organs involved is close (85%). Since data on carcinogenicity exist for several groups of pharmaceuticals, risk versus benefit evaluations should be made carefully in relation to possible clinical applications.

Effect of various chemicals on the aldehyde dehydrogenase activity of the rat liver cytosol

The cytosolic activity of aldehyde dehydrogenase (ALDH) was studied in the rat liver, after acute administration of various carcinogenic and chemically related compounds. Male Wistar rats were treated with 27 different chemicals, including polycyclic aromatic hydrocarbons, aromatic amines, nitrosamines, azo dyes, as well as with some known direct-acting carcinogens. The cytosolic ALDH activity of the liver was determined either with propionaldehyde and NAD (P/NAD), or with benzaldehyde and NADP (B/NADP). The activity of ALDH remained unaffected after treatment with 1-naphthylamine, nitrosamines and also with the direct-acting chemical carcinogens tested. On the contrary, polycyclic aromatic hydrocarbons, polychlorinated biphenyls (Arochlor 1254) and 2-naphthylamine produced a remarkable increase of ALDH. In general, the response to the effectors was disproportionate between the two types of enzyme activity, being much in favour for the B/NADP activity. This fact resulted to an inversion of the ratio B/NADP vs. P/NAD, which under constitutive conditions is lower than 1. In this respect, the most potent compounds were found to be polychlorinated biphenyls, 3-methylcholanthrene, benzo(a)pyrene and 1,2,5,6-dibenzoanthracene. Our results suggest that the B/NADP activity of the soluble ALDH is greatly induced after treatment with compounds possessing aromatic ring(s) in their molecule. It is not known, if this response of the hepatocytes is related with the process of chemical carcinogenesis.

Alcohol and drug use, family situation and school performance in adolescent children of alcoholics

A survey was conducted in a population of about 8000 Greek high school students (grades 9 and 12) in order to investigate factors possibly contributing to alcohol consumption. A self-rating multiple choice questionnaire was used. The present report focuses on students with alcoholic parents. Parameters studied include students' alcohol and drug use, school performance, family relationships, socioeconomic factors and parental control. In 3.3% of the sample parental alcoholism was reported. The results indicated that parental alcoholism is a strong predictor variable for the student's alcohol and drug use. Furthermore, predictability of the student's alcohol and drug use is increased when relatives' and friends' alcoholism are taken into account. Thus, family and/or peer actual alcohol use patterns appear to be a strong influence on adolescent alcohol and drug use. School performance is worse in children of alcoholics, and family situations (eg. divorces) as well as family dynamics (relationships with the family) are disturbed, in comparison with families of students with nonalcoholic parents. These results are discussed in terms of 'modelling' for drinking and drug behaviour and the socialisation process within the family.

Changes in the inducibility of a hepatic aldehyde dehydrogenase by various effectors

A hepatic soluble aldehyde dehydrogenase (ALDH), inducible by polycyclic aromatic hydrocarbons, was studied in Wistar rats in connection with substances known to affect drug metabolism or aldehyde dehydrogenase activity, such as phenobarbital (PB), disulfiram (DS), beta-diethylaminoethyl diphenylpropylacetate (SKF 525A) and calcium cyanamide (CC). 3-Methylcholanthrene (MC) was given as a model inducer of ALDH (100 mg/kg, i.p., as a single dose) and the animals were killed after 3 days. Pretreatment with PB (1 g/l drinking water, for 2 weeks) enhanced the inducing effect of MC. On the contrary, pretreatment with DS (100 mg/kg, i.p., daily x 4) reduced by 70% the expected increase in ALDH activity. Neither SKF 525A (25 mg/kg, i.p., daily x 4), nor CC (5 mg/kg, i.p., daily x 4) could affect the action of the inducer. At the above doses, basal ALDH activity was inhibited by DS (30%) and CC (70%), but was not affected at all by PB or SKF 525A. The results were somewhat different when the various effectors tested were administered to animals already treated with MC (20 mg/kg, i.p., daily x 6). In this case, DS did not affect the already induced ALDH activity. On the contrary, CC was still an effective inhibitor. Unexpectedly, post-treatment with SKF 525A further enhanced the initial induction brought about by MC. Our findings show that substances affecting microsomal drug metabolism can interfere with the process of ALDH induction by MC. The additive result of PB pretreatment is probably due to the enhanced accumulation of an active metabolite of MC.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue distribution of inducible aldehyde dehydrogenase activity in the rat after treatment with phenobarbital or methylcholanthrene

Two genetically distinct substrains of the Wistar rat (RR and rr) were used to study the tissue distribution of the inducibility of aldehyde dehydrogenase (ALDH). The RR substrain is responsive to phenobarbital (PB), as far as the induction of the hepatic ALDH activity is concerned, whereas the rr substrain is deprived of this biochemical property. Both substrains, however, respond to treatment with methylcholanthrene (MC), exhibiting a uniform increase of the ALDH activity in the liver. It is known that PB and MC induce two different isozymes of the hepatic cytosol. The effect of PB (1 g/l in drinking water, for 12 days) on the inducibility of ALDH in extrahepatic tissues was examined in the RR substrain. On the contrary, MC was given (50 mg/kg x 4, intraperitoneally) to rr animals. The activity of ALDH was found to be induced by PB in the liver and the intestinal mucosa, when measured with NAD and propionaldehyde (P/NAD) or phenylacetaldehyde (Ph/NAD). An increase of the activity was also noticed when ALDH was measured with NADP and benzaldehyde (B/NADP). In rr animals, MC induced the B/NADP activity in the liver, the intestinal mucosa, the kidneys, the lungs, the spleen, the brain, the urinary bladder and the heart. The effect of MC on various tissues was less distinct, when ALDH was measured as P/NAD or Ph/NAD activity. It is concluded, that PB and MC not only induce different types of ALDH activity, but they also reveal differences in the tissue distribution of the inducibility of ALDH.