Chronic ?-tetrahydrocannabinol during adolescence increases sensitivity to subsequent cannabinoid effects in delayed nonmatch-to-position in rats

Early-onset marijuana use has been associated with short- and long-term deficits in cognitive processing. In human users, self-selection bias prevents determination of the extent to which these effects result only from drug use. This study examined the long-term effects of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), the major psychoactive constituent of marijuana, in a delayed nonmatch-to-position task (DNMP). Male Long-Evans rats were injected daily with 10 mg/kg Δ⁹-THC during or after adolescence [postnatal days (PN) 21-50 or PN50-79, respectively] or with vehicle. On PN91, training in DNMP was initiated. Successful acquisition and pharmacological challenge began on approximately PN300. Decreases in accuracy were observed at lower doses of Δ⁹-THC in Δ⁹-THC-treated rats (versus vehicle-treated rats). Administration of chronic Δ⁹-THC at a younger age tended to enhance this effect. While anandamide did not decrease accuracy in any group, rats treated with Δ⁹-THC during adolescence initiated fewer trials at the 30 mg/kg dose of anandamide than did rats in the other two groups. To the extent tested, these differences were pharmacologically selective for cannabinoids, as scopolamine (positive control) decreased accuracy at the same dose in all groups and amphetamine (negative control) did not affect accuracy in any of the groups at doses that did not impair overall responding. These results suggest that repeated administration of a modest dose of Δ⁹-THC during adolescence (PN21-50) or shortly thereafter (PN50-79) produces a long-term increase in latent sensitivity to cannabinoid-induced impairment of performance in a complex operant task.     

Attenuation of amphetamine-induced motor stimulation and stereotypy by 6-hydroxydopamine in the rat

1. In accord with previous reports, intraventricular administration of 6-hydroxydopamine (250 μg) to rats did not influence spontaneous locomotor activity. Neither was the stereotyped behaviour seen after high doses of (+)-amphetamine (5 mg/kg) changed by this treatment. Increases in motor activity induced by (+)-amphetamine (0·5 and 1·0 mg/kg) were significantly reduced after 6-hydroxydopamine.

2. When 6-hydroxydopamine (250 μg) was administered to tranylcypromine (5 mg/kg) pretreated animals, spontaneous activity was significantly reduced. The stimulant effects of (+)-amphetamine (0·5 and 1·0 mg/kg) were completely abolished and amphetamine stereotypy (5·0 mg/kg) was absent or reduced after this treatment.

3. Bilateral injections of 6-hydroxydopamine (10 μg) into the substantia nigra abolished the more pronounced features of amphetamine stereotypy. However, although significantly reduced, amphetamine-induced locomotor stimulation was observed in these animals. Spontaneous activity was also reduced.

4. These observations suggest that dopaminergic nigro-striatal neurones mediate some of the stimulant effects of amphetamine as well as being of critical importance in amphetamine-induced stereotypy. However, other catecholaminergic neurones also appear to be involved in amphetamine motor stimulation. The results are consistent with the view that amphetamine exerts its behavioural effects indirectly through its action on brain catecholamines.

     

The effect of amantadine and (+)-amphetamine on motility in rats after inhibition of monoamine synthesis and storage

The effect of amantadine and (+)-amphetamine on motility was investigated by subcutaneous administration to rats. Amantadine 50 and 100 mg/kg induced a moderate increase of motility. (+)-amphetamine 1, 2.5 and 5 mg/kg showed a more potent locomotor stimulant effect. A stereotyped licking was found during the hypermotility induced by (+)-amphetamine 5 mg/kg.Pretreatment with the catecholamine synthesis inhibitor -methyl-p-tyrosine inhibited the effect of (+)-amphetamine but not that of amantadine. Reserpine potentiated the effects of both amantadine and (+)-amphetamine. Tetrabenazine antagonized the hyperactivity produced by (+)-amphetamine but potentiated amantadine induced hyperactivity. The locomotor stimulant effect of amantadine seems to differ in certain respects from that of amphetamine.     

The influence of prolonged amphetamine treatment and amphetamine withdrawal on brain biogenic amine content and behaviour in the rat

Male Wistar rats were treated orally with D-l-amphetamine sulphate in a dose of 3 mg/kg daily during 9 months. An increase of locomotor activity during the first 3 months was observed, while in the following 6 months locomotor activity was similar to the control group. The estimations of noradrenaline and 5-hydroxytryptamine levels in 9 discrete areas of brain, after 9 months of amphetamine treatment showed no changes in 5-HT level, but a significant decrease of the noradrenaline level in the pons. Withdrawal of amphetamine from rats treated for 9 months with this drug caused an inhibition of locomotor activity and a decrease of noradrenaline and 5-hydroxytryptamine level in the cerebellum.     

Amphetamine-induced inhibition of tyrosine hydroxylation in homogenates of rat corpus striatum.

Tyrosine hydroxylase activity was measured in vitro by following the rate of production of ¹⁴CO₂ from [¹⁴C]-DOPA newly formed from L-[1-¹⁴C]-tyrosine in a crude synaptosomal preparation of striatal homogenates which contained only endogenous pteridine cofactor. Administration of (+)-amphetamine in vivo (0·50–5·0 mg/kg, i.p.) led to a specific local inhibition of tyrosine hydroxylase activity, after a 15–30 min delay and persisted for at least 4 hr (50% inhibition at 2·5 mg/kg), in nerve endings prepared from the corpus striatum of the rat brain. (?)-Amphetamine was less potent (25% inhibition at 5 mg/kg). There was no change in the level of tyrosine hydroxylase in cell-free extracts and no inhibition of substrate-uptake into nerve endings or change in the level of endogenous tyrosine. When striatal nerve endings were exposed directly to amphetamine in vitro (10 μM), stimulation rather than inhibition of tyrosine hydroxylation occurred, although the hydroxylated metabolites p-hydroxyamphetamine and p-hydroxynorephedrine inhibited the reaction (at 0·1–10 μM). Nevertheless, the inhibitory effect of (+)-amphetamine in vivo persisted in the rat after blockade of microsomal oxidases with SKF-525A (40 mg/kg, i.p.) as well as in the guinea pig, a species in which amphetamine is weakly p-hydroxylated. Interruption of impulse flow in the nigro-striatal pathway by electrothermic lesions was found to decrease tyrosine hydroxylase activity in the striatum, possibly as a result of an increased intraneuronal accumulation of dopamine which could enhance the end-product feedback inhibition of tyrosine hydroxylase. Inhibitory effects of in vivo administration of amphetamine on tyrosine hydroxylase activity in striatal synaptosomes may similarly be mediated by a decreased impulse flow in striatal dopamine neurones. The inhibitory effect of (+)-amphetamine (5 mg/kg, i.p.) was interrupted by blockade of striatal dopamine-receptors with chlorpromazine (10 mg/kg, i.p.) and by blockers of γ-aminobutyric acid-receptors (bicuculline or picrotoxin, 2·5 mg/kg, i.p.). Local striatal receptors of dopamine may thus be involved in this action of amphetamine or descending γ-aminobutyric acid-neurones may mediate a neurophysilogical feedback regulation of activity in the nigro-striatal pathway.     

Differences between (+)- and (−)-amphetamine in effects on locomotor activity and l-dopa potentiating action in mice

Summary The l-Dopa-potentiating effects of the two optical isomers of amphetamine, as well as the effects of their own, were investigated in mice, using locomotor activity as test parameter. The study was performed in three steps. First, the time-course were studied for the effects of (+)- and (–)-amphetamine and l-Dopa. Second, dose-response relationships were established for the amphetamine enantiomers. Third, the l-Dopa-potentiating effects, of a few, selected doses of the amphetamine isomers were investigated by establishing dose-response curves for l-Dopa with and without the amphetamines. All animals given l-Dopa were pretreated with an inhibitor of extracerebral aromatic amino acid decarboyxlase. (+)-Amphetamine, 0.5–8 mg/kg, caused a dose-dependent stimulation of locomotoractivity, whereas (–)-amphetamine, 1–4 mg/kg, caused a dose-dependent depression. Doses higher than 8 mg/kg of the laevo-isomer caused stimulation of the activity. (+)-Amphetamine, 0.25 mg/kg, and (–)-amphetamine, 0.5 mg/kg, i.e. doses without any effect on locomotor activity of their own, caused virtually the same shift to the left of the dose-response curve for l-Dopa. (–)-Amphetamine, 4 mg/kg which per se caused depression of locomotor activity, caused a marked potentiation of the l-Dopa-induced stimulation of motor activity. Thus, there does not exist a close correlation between the l-Dopa-potentiating action of the amphetamines and their stimulating properties per se.     

Reproductive and teratologic studies with Δ9-tetrahydrocannabinol and crude marijuana extract

Synthetic Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and crude marijuana extract (CME) containing 16% Δ⁹-THC were administered orally to albino rats at doses of 0.5, 1.5, and 5 mg of Δ⁹-THC from either source/kg body weight. In the general reproductive study, males were dosed from 60 days prior to mating until termination of mating and females were dosed from 14 days prior to mating until 21 days postpartum. Mating and fertility indices were similar for control and treatment groups. No differences between control and treatment groups were seen at an interim sacrifice on gestation Day 14 with respect to corpora lutea, implantation sites, resorption sites, and viable fetuses. The average numbers of pups delivered and viable at birth did not differ among control and treatment groups, and pup survival was unaffected by treatment. In a perinatal/lactation study, females were dosed from gestation Day 15 until lactation Day 21. No adverse effects of treatment were observed directly or in a cross-fostering study. No evidence of teratogenic activity was obtained for either Δ⁹-THC or CME at Δ⁹-THC equivalent doses of 5, 15, and 50 mg/kg on gestation Days 6–15 in rats and 0.5, 1.5, 5, and 15 mg/kg on gestation Days 6–18 in rabbits. Fetal survival and pup survival were reduced at the highest CME treatment level.     

Evidence for dissociable mechanisms of amphetamine-and stress-induced behavioral sensitization: effects of MK-801 and haloperidol pretreatment

The present study examined the ability of pretreatment with MK-801 or haloperidol to block the induction of behavioral sensitization to amphetamine challenge by repeated immobilization stress in male Sprague-Dawley rats. Fifteen minutes before each of ten 30-min restraint sessions, rats were administered saline, MK-801 (0.01, 0.10 or 0.25 mg/kg IP) or haloperidol (0.10 or 0.25 mg/kg IP). Control rats received the same injection regimen without restraint. An additional experiment examined the ability of MK-801 to block the induction of sensitization by repeatedd-amphetamine. In this experiment, rats were administered saline or MK-801 (0.25 mg/kg IP) 15 min before each of ten amphetamine injections (1.0 mg/kg IP, administered under the same regimen as immobilization stress). Four days after the final immobilization or amphetamine injection, rats were tested for locomotor response to novelty, saline andd-amphetamine (1.5 mg/kg IP). Exposure to repeated immobilization stress significantly enhanced the locomotor response to amphetamine challenge but not to saline challenge whether rats were pretreated with saline, MK-801 or haloperidol. Secondary analysis of dose effects in each pretreatment group revealed that at 0.25 mg/kg, repeated MK-801 in itself induced sensitization to the response to amphetamine in control rats and potentiated stress-induced sensitization in restrained rats. In contrast, the sensitization induced by repeated amphetamine was attenuated by MK-801 pretreatment. Neither dose of haloperidol affected the locomotor response to saline or amphetamine in control or stressed rats. These results indicate that the effects of MK-801 on the induction of sensitization are complex and suggest that amphetamine-and stress-induced behavioral sensitization may arise through different mechanisms.     

THE LACK OF β-ADRENOCEPTOR INVOLVEMENT IN THE CARDIAC ACTION OF Δ1-TETRAHYDROCANNABINOL IN RATS

1. Rat isolated hearts perfused with Δ¹-THC (0·5 μ/ml) showed a reduction in the rate of beating which was not altered by pretreatment with propranolol (2 μg/ml), atropine (4 μg/ml) or hexamethonium (4 μ/ml). 2. Propranolol (2 μg/ml) also caused a decrease in the rate of beating, which was not affected by pretreatment with Δ¹-THC (0·5 μg/ml). 3. In pithed rats, propranolol (2 mg/kg, i.v.) caused a decrease in the pulse rate, which was not altered by prior administration of Δ¹-THC (1 mg/kg, i.v.). 4. In both preparations, the responses to isoprenaline were markedly reduced or abolished by propranolol, but they were unaffected by Δ¹-THC. 5. It is concluded that the hypotensive and cardiac slowing actions of Δ¹-THC are not mediated by activation of parasympathetic nerves or by β-adrenoceptor blockade.     

Antipyretic, analgesic and anti-inflammatory effects of delta 9-tetrahydrocannabinol in the rat

The effects on body temperature produced by graded doses of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and phenylbutazone were compared in both normal and pyretic rats. Dose related hypothermic responses were produced by the oral administration of Δ⁹-THC in normal animals. Moreover, Δ⁹-THC significantly reduced elevated temperatures in yeast-induced pyretic rats to near normal levels at doses which exhibited little hypothermic activity in normal rats. The oral antipyretic potency of Δ⁹-THC was approximately 2 times that of phenylbutazone. The comparative oral antinociceptive activity of Δ⁹-THC and selected narcotic and non-narcotic analgesics was determined by the increase in response latency to pressure applied to normal and yeast-inflamed paws. Δ⁹-THC administered orally was essentially inactive at dose levels below those producing pronounced central nervous system depression. The oral anti-inflammatory efficacy of Δ⁹-THC was compared to phenylbutazone and acetylsalicylic acid. Δ⁹-THC was ineffective in inhibiting carrageenin-induced edema of the rat paw following acute or chronic administration.     

On the central mediation of anorexigenic drug effects

The anorexigenic effects of d-amphetamine and of d-p-chloroamphetamine have been compared in male rats; the p-chloro compound proved to be 1·5?2 times more active than d-amphetamine. The suppression of food intake provoked by an ed₉₅ of d-amphetamine could be antagonized by the following treatments: p-chlorophenylala-nine (300 mg/kg orally, twice, 72 and 48 hr before the experiment), cyproheptadine (0·4?1·6 mg/kg i.p.), α-methyltryosine (5 and 10 mg/kg i.p.), disulfiram (200–600 mg/kg orally), phentolamine (0·5 and 1 mg/kg i.p.) and haloperidol (0·03?0·4 mg/kg i.p.). All these treatments either reduced the hypothalamic turnover of noradrenaline or blocked the receptors of this amine, which therefore is considered as the mediator of the anorexigenic effect of amphetamine. The effect of an ed₉₅ of d-p-chloroamphetamine was antagonized by p-chlorophenylalanine, α-methyltyrosine and disulfiram in the doses mentioned above. Cyproheptadine had an effect only with the lowest dose used, and the antagonistic effects of phentolamine and especially of haloperidol were much weaker than in the case of amphetamine. These antagonistic effects and the alterations in levels and turnover of hypothalamic 5-HT, noradrenaline and dopamine suggest a participation of catecholamines and 5-HT in the mediation of the anorexigenic effect of p-chloroamphetamine.     

The identification, isolation, and preservation of delta-9-tetrahydrocannabinol (delta-9-THC)

(—)-trans-Δ⁹-Tetrahydrocannabinol (Δ⁹-THC) was isolated from marihuana plant extract, by adsorptive column and glc. The adsorptive column chromatography method consisted of chromatographing marihuana extract on a column packed with a mixture of silica gel (gas chromatography grade (100/120 mesh), silver nitrate and calcium sulphate (CaSO₄·H₂O) (3:1:0·5) with benzene as the eluting solvent. The glc method consisted of chromatographing the extract on a 3 ft silanized glass column (3/8 inch o.d.) packed with 1·5 ft of 2% QF-1 and 1·5 ft of 2% OV-17 on chromosorb W, AW 30–60 mesh, prep grade. A purity of 99% for the isolated Δ⁹-THC was confirmed by infrared spectroscopy, nuclear magnetic resonance, mass spectroscopy. The effects of storage conditions on Δ⁹-THC stability, monitored by glc, indicated the best method for preserving Δ⁹-THC was at 0°, protected from light, stored under nitrogen.     

Effect of chlorpromazine on mouse ambulatory activity sensitization caused by (+)-amphetamine

Abstract— The development of sensitization to the ambulation-increasing effect of (+)-amphetamine (2·5 mg kg^?1) was found to be dose-dependently inhibited when 1 or 2 mg kg^?1 chlorpromazine was administered concomitantly, and the sensitization to (+)-amphetamine was almost completely suppressed when co-administered with 4 mg kg^?1 chlorpromazine. Following a challenge dose of 2·5 mg kg^?1 (+)-amphetamine, mice pretreated with (+)-amphetamine alone or with (+)-amphetamine plus 1 or 2 mg kg^?1 chlorpromazine showed similar marked enhancement of the sensitization. However, mice that had been given (+)-amphetamine plus 4 mg kg^?1 chlorpromazine displayed only slight enhancement of the effect compared with the activity level in saline-pretreated mice.     

The effects of chronic treatment with d-amphetamine on food intake,body weight,locomotor activity and subcellular distribution of the drug in rat brain

Female Wistar rats were treated chronically with d-amphetamine sulphate in drinking water. The concentrations of amphetamine were 0.01%, 0.02%, 0.03%, 0.04% and 0.05% in the 1st, 2nd, 3rd, 4th, and 5th week of treatment. The consumed doses of amphetamine increased from 16 mg/kg on the first day up to 90 mg/kg on the 36th day of treatment. The effects of chronic treatment with amphetamine on food intake, body weight and locomotor activity of rats were determined. The rats developed tolerance to the overall toxicity and to the anorexigenic effect of maphetamine. No tolerance to the effects of the drug on body weight and locomotor activity was observed. The concentration of H³-d-amphetamine in brains of chronically treated rats is significantly higher than in controls. No difference in the pattern of distribution of radioactivity among the subcellular fractions of rat brain was observed between control and chronically treated groups. The relationship between developmen tof tolerance and the concentration of amphetamine in the brain is discussed.     

The pharmacological activity of inhalation exposure to marijuana smoke in mice

Although the majority of cannabinoid users smoke marijuana, the preponderance of laboratory animal research is based on administration of Delta9-tetrahydrocannabinol (Delta9-THC) or other cannabinoid agents via injection. The aim of the present study was to evaluate the impact of inhaling marijuana, or ethanol-extracted placebo smoke in the mouse model of cannabinoid activity by assessing inhibition of spontaneous activity, antinociception, catalepsy, and body temperature. In order to determine dosimetry, blood levels of Delta9-THC were obtained following either marijuana exposure or intravenous injection of Delta(9)-THC. Inhalation exposure to marijuana produced dose-related increases in antinociception and catalepsy, with estimated ED50 doses of Delta9-THC of 2.4 and 3.8 mg/kg, respectively. However, hypothermia and locomotor depression occurred in both the placebo- and marijuana-exposed mice. The CB1 receptor antagonist, SR 141716A antagonized the antinociceptive effects of marijuana (AD50 = 0.6 mg/kg), but only slightly decreased marijuana-induced catalepsy, and failed to alter either the hypothermic or locomotor depressive effects. In contrast, SR 141716A antagonized the antinociceptive, cataleptic, and hypothermic effects of intravenously administered Delta9-THC in mice that were exposed to air alone, though all subjects exhibited locomotor depression, possibly related to the restraint. In accordance with reports of others, these data suggest that exposure to smoke alone has pharmacological consequences. Our findings also indicate that marijuana-induced antinociception is mediated through a CB1-receptor mechanism of action and are consistent with the notion that Delta9-THC is mainly responsible for this effect.     

Effects of scopolamine and d-amphetamine on locomotor activity before and after shock: A diallel analysis in mice

The effect of shock on locomotor activity was evaluated in three strains of mice (A, DBA/2 and C57BL/6) after treatment with scopolamine (1.0 mg/kg) and d-amphetamine (10.0 mg/kg). The effectiveness of either drug in increasing locomotor activity was strain dependent. Both drugs eliminated behavioral suppression induced by shock, and in A and DBA/2 mice shock augmented the locomotor stimulation induced by d-amphetamine. In another experiment the behavior of the 6 F₁ hybrids was examined in relation to the parent strains. It was observed that locomotor activity in the F₁'s could resemble that seen in one parent in the saline condition, but the other parent after treatment with d-amphetamine. Similarly, the F₁ behavior in the amphetamine condition was not predictive of the behavior seen after shock plus amphetamine. The results suggest that general activity, locomotor activity after amphetamine treatment, and responsiveness following shock in amphetamine-treated mice are mediated by different genetic mechanisms.     

Chronic treatment with Delta(9)-tetrahydrocannabinol enhances the locomotor response to amphetamine and heroin. Implications for vulnerability to drug addiction.

Cannabis sativa preparations are some of the most widely used illicit recreational drugs. In addition to their direct addictive potential, cannabinoids may influence the sensitivity to other drugs. The aim of the present study was to determine if a cross-sensitization between Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and other drugs (amphetamine and heroin) could be demonstrated. We examined the effects of a chronic treatment with Delta(9)-THC (0.6, 3 and 15mg/kg, ip) on the locomotor response to amphetamine (1mg/kg, ip) and heroin (1mg/kg, ip). Chronic treatment with Delta(9)-THC resulted in tolerance to the initial hypothermic and anorexic effects. Pre-treatment with Delta(9)-THC increased the locomotor responses to amphetamine and heroin. This cross-sensitization was time-dependent as it was observed three days after the last injection of Delta(9)-THC for amphetamine, and a relatively long time after the end of chronic treatment (41 days) for heroin. Moreover, the enhanced response to amphetamine or heroin was noted in some individuals only: the high-responder rats (HR). These animals have previously been shown to be vulnerable to drug taking behaviors. It is hypothesised that repeated use of Cannabis derivates may facilitate progression to the consumption of other illicit drugs in vulnerable individuals.     

Interaction between d-amphetamine and ethanol with respect to locomotion,stereotypies, ethanol sleeping time,and the kinetics of drug elimination

The interaction between d-amphetamine and ethanol with respect to locomotor activity, stereotyped behavior, and sleeping time was investigated in rats. Ethanol 0.8 g/kg i.p. enhanced and prolonged locomotor activity produced by d-amphetamine 1 mg/kg s.c. The increased motility after 5 mg/kg d-amphetamine was not influenced by alcohol 0.8 g/kg i.p. or 3.2 g/kg orally, but slightly protracted. Stereotyped head and paw movements as well as stereotyped licking, were distinctly strengthened and protracted by 3.2 g/kg ethanol orally. The modified d-amphetamine motility and stereotypies can be explained by alcohol-induced prolongation of the life of d-amphetamine. The effect is produced by alcohol's inhibition d-amphetamine p-hydroxylation in rat liver. After 3.2 g/kg ethanol i.p., the sleeping time of male rats amounted to 153 min. Simultaneous administration of 5 mg/kg d-amphetamine s.c. reduced the sleeping time to 84 min. This is obviously based on a central antagonism.     

The effect of Δ-tetrahydrocannabinol on the uptake and release of C-dopamine from crude striatal synaptosomal preparations

Δ⁹-Tetrahydrocannabinol (Δ⁹-THC) and a water soluble ester derivative (compound I) caused a concentration-related decrease in the uptake of ¹⁴C-dopamine into crude synaptosomal preparations derived from mouse striata. Both were less potent than amphetamine in this preparation. In the presence of 10^?7m amphetamine the IC₅₀ of Δ⁹-THC was unaffected. The IC₅₀ is the concentration of drug in the medium which will inhibit the uptake of ¹⁴C-dopamine into the synaptosomes by 50%. However in the presence of 3.0 × 10^?6m Δ⁹-THC, the dose response curve to amphetamine was shifted to the right and the IC₅₀ of amphetamine was increased. Δ⁹-Tetrahydrocannabinol and compound I increased the release of ¹⁴C-dopamine from preparations pre-incubated with ¹⁴C-dopamine. The effect was small but significant. The effects of amphetamine and Δ⁹THC combined were additive on this system. The mode of action of Δ⁹-THC with regard to the dopaminergic system of the striatum is discussed.     

Endocrine effects of cannabis in male rats

Male Wistar rats were administered either synthetic Δ⁹-tetrahydrocannabinol (Δ⁹-THC) or Mexican cannabis extract at doses of 1, 5, 10, 25, and 50 mg of Δ⁹-THC/kg of body weight. Steroid concentrations in urine and blood were measured using glass capillary gas chromatography and individual metabolites were identified by gas chromatography/mass spectrometry. Plasma corticosterone and its metabolite were elevated in a dose-response fashion up to 25 mg/kg. While testosterone is unaltered by Δ⁹-THC, except at 50 mg/kg, ⊙ther metabolites with possible relation to androgen metabolism were elevated. Measurable amounts of estrogens were produced by male rats given the drugs. Additional alterations were seen in the concentrations of conjugated steroids.