Reduction of carcinogen-induced breast cancer in rats by an anti-fertility drug

The DMBA (dimethylbenz[a]anthracene)-induced mammary cancer systems seemed to be an ideal model for the study of the influence of oral contraceptives (OCs) on endocrine-related cancers. Groups of 20 female Sprague-Dawley rats, age 40-45 days, weight approximately 150 g, were given 3.0 or 0.3 mg of crystalline Enovid suspended in 1 ml of sesame oil per dose for 45 days. The controls consisted of a group of 20 rats given a single dose of 15 mg of DMBA, of 2 groups of 10 rats administered daily doses of 3.0 and 0.3, respectively, of Enovid for 45 days, and of 1 group of 20 rats on sesame oil. In addition to these 6 groups, 3 additional sets of 5 rats each were fed 3.0 or 0.3 mg Enovid per rat, or 0.3 mg Enovid plus the subsequent single dose of 15 mg DMBA. The animals were weighed weekly and thoroughly examined for the appearance of mammary tumors or other grossly apparent lesions. The dosage of Enovid was selected on the basis of preliminary experiments. With doses of 0.005 mg per 150 g rat the estrus cycle was usually but not always arrested 5 days after the treatment began. At doses of 0.05 and 0.5 mg the cycle was interrupted 3-5 days and at 1 day later. In the final studies with doses of 0.3 and 3.0 mg, the microscopic examination of the smears indicated that the estrus cycle was effectively halted in all rats throughout the Enovid, or Enovid plus carcinogen feeding period but returned to normal shortly after the cessation of Enovid administration. DMBA failed to restore the estrus cycle suggesting that Enovid exerts a pronounced effect on the endocrine system. A single dose of 15 mg DMBA yielded an increasing incidence of mammary tumors which reached 100% after about 6 months. The multiplicity also rose and reached an average of 5.8 masses per rat at the end of the planned experiment period of 9 months. Histopathologic examination of the tumors indicated that there were several types, and even the same tumor nodule exhibited areas of varying morphologic aspect. Administration of the lower level of Enovid tended to inhibit slightly the incidence of mammary cancer. Of the 20 sesame oil control animals, only 1, killed after 237 days, had a large fibroadenoma.     

Isolation and hypoglycemic activity of 5, 7,3'-trihydroxy-3,6,4'-trimethoxyflavone from Brickellia veronicaefolia.

Hypoglycemic activity-guided fractionation together with chemical analysis led to the isolation of one flavone (5, 7,3'-trihydroxy-3,6,4'-trimethoxyflavone) from the chloroform extract of the leaves of Brikkellia veronicaefolia. Identification was based on spectroscopic methods. The isolated flavone was tested for hypoglycemic activity in normal and alloxan-diabetic CD1 mice (25-30 g) were administered in doses of 10, 25 and 50 mg/kg body weight. The blood glucose levels were determined before and 1.5, 3, 4.5 and 24 hours after drug administration. The results showed that the flavone produces a significant hypoglycemic effect in normal as well as in diabetic mice. Comparison was made between the action of the flavone and a known hypoglycemic drug as tolbutamide (50 mg/kg). The flavone was found to be slow and less effective than tolbutamide.     

Modulatory influences of tamoxifen, tocopherol, retinyl acetate, aminoglutethimide, ergocryptine and selenium on DMBA-induced initiation of mammary carcinogenesis in rats

Present study evaluates the chemopreventive actions of tamoxifen (10 mg/kg), retinyl acetate (50 mg/kg), tocopherol (200 mg/kg), aminoglutethimide (1 mg/kg), ergocryptine (5 mg/kg), and sodium selenite (1 mg/kg) when given singly/in combinations on the initiation of mammary carcinogenesis induced by 20 mg of DMBA in virgin female rats. DMBA was given when rats were 50 days old and the modulators were given in diet 10 days before and 10 days after carcinogen treatment and experiments were terminated 6 months later. DMBA alone yielded tumors in 62% rats. When modulators were given singly and in combinations of two, tumor incidences were not altered significantly. The range of tumor incidences was between 30% and 13% when the agents were given in combinations of 3, 4 and 5. Finally when all 6 modulators were given together the tumor incidence dropped down to 8.3%.     

Comparison of anorectic drugs in rats trained to discriminate between satiation and deprivation

Eight male rats were trained to discriminate between the internal states produced by food deprivation of 3 hours (satiation) and that produced by food deprivation of 27 hours duration (deprivation). One lever, in a two-lever operant chamber, had to be pressed to receive reinforcement in the satiation state, whereas pressing the other lever was required when the rat was in the deprivation state. Once the rats were trained, increasing the number of hours of food deprivation, from 1 to 48 hours, resulted in more deprivation-appropriate lever responses in the two-lever operant task. Administration of doses of fenfluramine (0.5-1.5 mg.kg), its active metabolite norfenfluramine (0.25-1.0 mg/kg) or d-amphetamine (0.5-1.5 mg/kg) produced a dose-responsive decrease in deprivation-appropriate responses when each drug/dose was injected (i.p.) 15 min prior to deprivation (27 hours) testing. Norfenfluramine was 1.5 times more potent than fenfluramine which was 1.5 times more potent than amphetamine.     

Stimulatory effect of 1 alpha, 25-dihydroxyvitamin D3 on the formation of skin tumors in mice treated chronically with 7,12-dimethylbenz[a]anthracene

The effect of 1 alpha, 25-dihydroxyvitamin D3 (1 alpha, 25-(OH)2D3) and its 24,24-difluoro analog on the formation of skin tumors in mice was evaluated in a complete carcinogenesis model using 7,12-dimethylbenz[a]anthracene (DMBA) as the carcinogen. Twice weekly topical application of 0.25-0.50 nmol of 1 alpha, 25-(OH)2D3 or 0.05-0.10 nmol of the difluoro analog of 1 alpha, 25-(OH)2D3 1 hour prior to treatment with 50 nmol DMBA stimulated tumor formation several fold compared to animals receiving DMBA alone. Topical application of 0.50 nmol of 1 alpha, 25-(OH)2D3 24 hours after treatment with DMBA, or half of this dose of the vitamin D3 metabolite, applied 1 hour before and 24 hours after treatment with DMBA, also stimulated tumor formation several fold. These results are in marked contrast to the potent inhibitory effect of 1 alpha, 25-(OH)2D3 and its difluoro analog on the formation of skin tumors in mice promoted by 12-O-tetradecanoylphorbol-13-acetate.     

Transplacental penetration of 7,12-dimethylbenz(a)anthracene and its distribution in the organs of rat fetuses]

Rats were given 7,12-dimethylbenz(a)anthracene (DMBA) intravenously in a dose of 15 mg/kg on the 21st day of pregnancy; its content in the liver, placenta, and the fetus was determined by the fluorescent-spectral method. The maximal concentration was reached in 10--15 min in the liver and placenta of the pregnant rats (45 and 6.3 microgram/kg, respectively) in comparison with a slower (in one hour) elevation in the fetal tissues (2.4 microgram/kg). It took about 5 hours for all the tissues to be cleared of the carcinogen. One hour after the administration DMBA was unevenly distributed in various fetal organs--the maximal content in the liver, and the minimal--in the "carcass" in comparison with the content in other organs (the kidneys, lungs, brain, intestine). The results obtained failed to correlate with the data on the predominant origination of the tumours in the kidneys and the nervous system of rats in transplacental DMBA action.     

Behavioral interactions between ethanol and imidazodiazepines with high affinities for benzodiazepine receptors

The intrinsic effects of two imidazodiazepines RO 15-3505 and RO 17-1812 on the behavior of mice in a holeboard test were investigated. The interactions of these two drugs with ethanol were also studied. RO 15-3505 (0.75-6.0 mg/kg) failed to significantly alter either exploratory head-dipping or locomotor activity when administered alone but doses of 0.75 and 1.5 mg/kg reversed the reduction in the number of head-dips caused by ethanol (2 g/kg) and partially reversed ethanol's locomotor stimulant action. In contrast, RO 17-1812 (0.75-6.0 mg/kg) increased locomotor activity when administered alone, and enhanced the reduction in exploration caused by ethanol. Neither RO 15-3505 nor RO 17-1812 altered blood alcohol concentrations suggesting a pharmacodynamic basis for these interactions. The results suggest that in the holeboard test the interactions of imidazodiazepines with ethanol are related to the nature of their interaction with benzodiazepine receptors, inverse agonists antagonising and agonists enhancing ethanol's effects on exploration.     

Effect of fluoxetine and metergoline on amphetamine-induced rise in plasma corticosterone

The effect of the serotonin reuptake inhibitor, fluoxetine, and the serotonin antagonist, metergoline, on the rise in plasma corticosterone induced by amphetamine was studied in the conscious, unrestrained rat. Fluoxetine (2.5 mg/kg) did not affect plasma corticosterone. However, this dose of fluoxetine when administered two hours prior to amphetamine (0.1 or 0.5 mg/kg) significantly potentiated the amphetamine-induced rise in plasma corticosterone. Fluoxetine had no effect on the response induced by the highest dose of amphetamine (1.0 mg/kg) utilized in the study. In contrast, metergoline produced a dose-dependent increase in plasma corticosterone over the range 0.1 – 5.0 mg/kg. This response reached maximum 30 minutes after drug administration and had a duration of approximately 120 minutes. Pretreatment of animals with metergoline (5.0 mg/kg) three hours before the administration of amphetamine (1.0 mg/kg) resulted in a significant decrease in the corticosterone rise induced by amphetamine. Lower doses of metergoline were ineffective in reducing the amphetamine-induced response. These observations support the hypothesis that the amphetamine-induced rise in plasma corticosterone is due, in part, to stimulation of serotonergic neurons.     

Persistent and heritable structural damage induced in heterochromatic DNA from rat liver by N-nitrosodimethylamine

Analysis, by benzoylated DEAE-cellulose chromatography, has been made of structural change in eu- and heterochromatic DNA from rat liver following administration of the carcinogen N-nitrosodimethylamine (10 mg/kg body weight). Either hepatic DNA was prelabeled with [3H]thymidine administered 2-3 weeks before injection of the carcinogen or the labeled precursor was given during regenerative hyperplasia in rats treated earlier with N-nitrosodimethylamine. Following phenol extraction of either whole liver homogenate or nuclease-fractionated eu- and heterochromatin, carcinogen-modified DNA was examined by stepwise or caffeine gradient elution from benzoylated DEAE-cellulose. In whole DNA, nitrosamine-induced single-stranded character was maximal 4-24 h after treatment, declining rapidly thereafter; gradient elution of these DNA preparations also provided short-term evidence of structural change. Following incubation of purified nuclei with micrococcal nuclease, 10-12% of labeled DNA was solubilized (eu-chromatin) by 1.0 unit of micrococcal nuclease (5 mg of DNA)-1 mL-1 after 9 min. In prelabeled animals, administration of N-nitrosodimethylamine caused a marked fall in the specific radioactivity of solubilized DNA, while that of sedimenting DNA was not affected. Caffeine gradient chromatography suggested short-term nitrosamine-induced structural change in euchromatic DNA, while increased binding of heterochromatic DNA was evident for up to 3 months after carcinogen treatment. Preparations of newly synthesized heterochromatic DNA from animals subjected to hepatectomy up to 2 months after carcinogen treatment provided evidence of heritable structural damage. Carcinogen-induced binding of heterochromatic DNA to benzoylated DEAE-cellulose was indicative of specific structural lesions whose affinity equalled that of single-stranded DNA up to 1.0 kilobase in length.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phase shifting the circadian rhythm of neuronal activity in the isolated Aplysia eye with puromycin and cycloheximide. Electrophysiological and biochemical studies

The effects of pulse application of puromycin (PURO) or cycloheximide (CHX) were tested on the circadian rhythm (CR) of spontaneous compound action potential (CAP) activity in the isolated Aplysia eye. CAP activity was recorded from the optic nerve in constant darkness at 15degreesC. PURO pulses (6, 12 h; 12--134 mug/ml) and CHX pulses (12 h, 500--2,000 mug/ml) caused dose-dependent phase delays in the CR when administered during projected night. PURO pulses (6 h, 125 mug/ml) caused phase advances when given during projected day and caused phase delays when given during projected night. In biochemical experiments PURO (12 h, 20 mug/ml) and CHX (12 h, 500 mug/ml) inhibited leucine incorporation into the eye by about 50%. PURO (12 h; 50, 125 mug/ml) also changed the molecular weight distribution of proteins synthesized by the eye during the pulse. The effect of PURO (12 h, 125 mug/ml) on the level of incorporation was almost completely reversible within the next 12 h but the phase-shifted eye showed an latered spectrum of proteins for up to 28 h after the pulse. In electrophysiological experiments spontaneous CAP activity and responses to light were measured before, during, and after drug treatments. In all, eight parameters in three periods were analyzed quantitatively. Of these 24 indices, only 3 showed significant changes. PURO increased spontaneous CAP frequency by 67% 0-7 h after the drug pulse and increased the CAP amplitude of the tonic light response by 23% greater than 7 h after the pulse. CHX increased the intraburst spontaneous CAP frequency by 33% during the pulse and CAP frequency of the tonic light response by 32% 0- 7 h after the pulse. The above data indicate that phase-shifting doses of PURO and CHX inhibit protein synthesis in the eye without causing adverse electrophysiological effects, and suggest that protein synthesis is involved in the production of the CR of the isolated Aplysia eye.     

Effect of conjugated linoleic acid mixture supplemented daily after carcinogen application on linoleic and arachidonic acid metabolites in rat serum and induced tumours

Conjugated linoleic acid (CLA) is thought to exert anticarcinogenic, antiatherogenic, anti-inflammatory and weight loss effects. The impact on eicosanoid biosynthesis may be one of the mechanisms of its action. The aim of this study was to establish whether CLA mixture supplemented daily after administration of carcinogen (7, 12-dimethylbenz[a]anthracene, DMBA) influenced the concentration of linoleic and arachidonic acid metabolites: 13- or 9-hydroxyoctadecadienoic acids (13-, 9-HODE) and 15-, 12- or 5-hydroxyeicosatetraenoic acids (15-, 12- or 5-HETE) and prostaglandin E₂ (PGE₂) in rat serum and DMBA-induced tumours. The correlations between polyunsaturated fatty acids (PUFA) and HETE and HODE contents in serum were also investigated.Female Sprague–Dawley rats divided into three groups according to the diet (1% Bio-C.L.A., 2% Bio-C.L.A. and plant oil in the control group) were used in the study. On the 50th day of life some of the animals in every dietary group were administered DMBA to induce tumours. Since that day, the rats were fed one of the above-mentioned diets. After 15 weeks the animals were sacrificed and blood and tumours were collected. HETE and HODE were extracted using a solid-phase extraction (SPE) method on C18 columns and analysed with LC-MS/MS.The results of our study showed that CLA daily supplementation after carcinogen administration influence LA and AA metabolite levels in serum and tumours. However, the ratios of eicosanoids having opposite effects (e.g. 12-HETE/15-HETE), not concentrations of particular compounds, appear to be better indicators of pathological processes.     

Increase in Swimming Endurance Capacity of Mice by Capsaicin-induced Adrenal Catecholamine Secretion

Increase in endurance swimming capacity caused by capsaicin (CAP), a pungent component of red pepper, -induced increase of fat metabolism in mice was investigated using an adjustable-current water pool. The mice administered CAP via a stomach tube, showed longer swimming time until exhaustion than the control group of mice, in a dose-dependent manner. The maximal effect was observed at a dose of 10 mg/kg while more than 15 mg/kg had no effect. The increase of endurance was observed only when CAP was administered two hours before swimming. After the administration of CAP, the serum glucose concentration rapidly increased and then decreased within 60min, while the concentration of serum-free fatty acids gradually increased through 3 hours. The residual glycogen concentration of the gastrocnemius muscle after 30 min of swimming was significantly higher in the CAP-administered mice than in control mice, suggesting that use of the serum free fatty acids spared muscle glycogen consumption. The serum adrenaline concentration significantly increased with twin peaks at 30 min and two hours after administration of CAP. An experiment using adrenalectomized mice was done to confirm that the effect of CAP is due to increased energy metabolism through the secretion of adrenaline from the adrenal gland. The swimming endurance capacity of the adrenalectomized mice was not increased by CAP administration, although adrenaline injection induced a 58% increase in the endurance time. These results suggest that the increase of swimming endurance induced by CAP in mice is caused by an increase in fatty acid utilization due to CAP-induced adrenal catecholamine secretion.     

Effects of sc administration of recombinant human insulin-like growth factor I (IGF-I) on normal human subjects

Recombinant human insulin-like growth factor I (IGF-I) was administered subcutaneously to each of 5 normal human subjects at doses of 0 mg/kg (control), 0.06 mg/kg, or 0.12 mg/kg successively at one week intervals. After 0.06 mg/kg or 0.12 mg/kg IGF-I injections, plasma IGF-I levels increased from 185 +/- 17 ng/ml (mean +/- SEM) to maximal levels of 396 +/- 21 ng/ml at 3 hours and from 169 +/- 14 ng/ml to 480 +/- 27 ng/ml at 4 hours, respectively. These two peak values were statistically different (p less than 0.05). After 0.06 mg/kg and 0.12 mg/kg IGF-I administration, blood glucose levels decreased from 85 +/- 2 mg/dl to minimal levels of 73 +/- 3 mg/dl at 3 hours and from 83 +/- 1 mg/dl to 50 +/- 4 mg/dl at 2 hours, respectively. These two minimal values were statistically different (p less than 0.001). Serum insulin and C-peptide levels were decreased in a dose dependent manner after IGF-I administration. There were no changes between blood urea nitrogen levels before and 4 hours after IGF-I administration. The urinary GH concentration decreased after 0.06 mg/kg IGF-I administration, but increased and maintained normal values after 0.12 mg/kg IGF-I administration.     

Recombinant glucagon-like peptide-1 (7-36 amide) lowers fasting serum glucose in a broad spectrum of patients with type 2 diabetes.

AIMS: To evaluate the safety and efficacy of various doses of recombinant glucagon-like peptide-1 (7-36) amide (rGLP-1) administered subcutaneously (s. c.) via bolus injection or continuous infusion to lower fasting serum glucose (FSG) levels in subjects with type 2 diabetes treated by diet, hypoglycemic drugs, or insulin injection. METHODS: rGLP-1 was administered s. c. to 40 type 2 diabetics currently treated by diet, sulfonylurea (SU), metformin, or insulin in a double-blind, placebo-controlled, cross-over trial; preexisting treatments were continued during the study. In the bolus injection protocol, 32 subjects (8 from each of the 4 treatment groups) received 0.0, 0.5, 1.0, and 1.5 nmol rGLP-1/kg per injection (two injections, two hours apart, beginning one hour after the evening meal) in a randomized order on separate days. In the continuous s. c. infusion protocol, 40 subjects received rGLP-1 at 0.0, 1.5, 2.5, 3.5, and 4.5 pmol/kg/min for 10-12 hours overnight starting one hour after the evening meal. Fasting bloods were taken the morning after for glucose, insulin, and glucagon measurements. RESULTS: In the diet, SU, and metformin cohorts, bolus rGLP-1 injections produced modest reductions in mean FSG levels, averaging 17.4 mg/dl (7.3-27.5; 95 % CI) at the highest dose (p < 0.001 vs. placebo). Reductions in FSG levels were greater by continuous infusion at up to 30.3 mg/dl (18.8 - 41.8; 95 % CI; p < 0.001 vs. placebo). The greatest reduction in mean FSG occurred in the SU cohort (up to 43.9 mg/dl, 24.7 - 63.1; 95 % CI; p < 0.001). rGLP-1 infusions resulted in significant increases in fasting plasma insulin and decreases in fasting plasma glucagon levels. There were no serious adverse events; GI-related symptoms were dose-related and more commonly associated with injections. CONCLUSIONS: rGLP-1 (7-36) amide dose-dependently lowered FSG in a broad spectrum of type 2 diabetics when added to their existing treatment. Subcutaneous infusion was more effective than injection, and the combination with SU was more effective than with metformin.     

Combined stimulation of glucagon-like peptide-1 receptor and inhibition of cannabinoid CB1 receptor act synergistically to reduce food intake and body weight in the rat

Pharmacological activation of the glucagon-like peptide-1 (GLP-1) receptor and inhibition of the cannabinoid CB1 receptor were found to reduce food intake and body weight in humans and animals. Since earlier studies revealed that endocannabinoids may interact with other neurotransmitters to affect feeding behavior, we have examined whether a stable GLP-1 agonist, exendin-4 and a CB1 receptor antagonist, AM 251, may reciprocally enhance their inhibitory effects on food consumption in the rat. Additionally, we have tested whether the blockade of the GLP-1 receptor by exendin (9-39) modifies AM 251-dependent effects on energy balance. In a dose-response study, male Wistar rats were injected intraperitoneally with either 1.5-6.0 μg/kg exendin-4, 0.5-2 mg/kg AM 251, 80-320 μg/kg exendin (9-39) or their vehicle and the daily food and water intake as well as body weight changes were monitored two days before and two days after the injection. Exendin-4 at a dose of 3.0 and 6.0 μg/kg and AM 251 at a dose 2 mg/kg decreased significantly 24-hour food intake and body weight. Therefore, in the next study, the effects of lower doses of exendin-4 (1.5 μg/kg) and AM 251 (1.0 mg/kg) administered alone or together on food consumption were compared. As opposed to being injected alone, the co-administration of the two resulted in a marked decrease in both daily food intake and body weight. Exendin (9-39) did not modify the suppressory effect of the highest AM 251 dose on food consumption. Apparently, the effect of AM 251 on the appetite is not mediated by GLP-1. The concomitant stimulation of GLP-1 receptor and blockade of CB1 receptor, however, may act synergistically to inhibit appetite in the rat.     

CGS8216 noncompetitively antagonizes the discriminative effects of diazepam in rats

The benzodiazepine antagonist properties of CGS8216 were evaluated in rats trained to discriminate between saline and 1.0 mg/kg of diazepam in a two-choice, stimulus-shock termination procedure. CGS8216 (0.3 to 100 mg/kg) administered alone, either s.c., p.o. or i.p., occasioned only saline-appropriate responding. When administered concomitantly with a constant 1.0 mg/kg dose of diazepam, CGS8216 produced dose-related decreases in drug-appropriate responding. CGS8216 was most potent by the i.p. route, and approximately tenfold less potent by the oral route. CGS8216 was dermatotoxic after s.c. administration. CGS8216 i.p. had a long duration of action. A dose of 30 mg/kg completely antagonized the discriminative effects of the 1.0 mg/kg training dose of diazepam when the antagonist was administered 8 hr before the start of the test session. In order to determine the type of antagonism by CGS8216, the dose-effect curve for diazepam was redetermined in the presence of varying doses of CGS8216 (0.3 to 3.0 mg/kg, i.p.). CGS8216 produced a dose-related rightward shift in the diazepam dose-effect curve, but also decreased the slope and appeared to decrease the maximal effect. These results are consistent with the interpretation that CGS8216 antagonizes diazepam in a noncompetitive manner. It may do so because either it interacts with a subpopulation of benzodiazepine receptors, it functions as a pseudo-irreversible antagonist due to its high affinity, or because it is an antagonist with agonist properties.     

Interferon-inducing and immunostimulating activity of bonafton in an experiment

It was shown for the first time that the antiviral drug bonafton administered orally to nonlinear albino mice in single doses of 5, 12.5 and 25 mg/kg induced production of interferon in the animal blood serum. The maximum interferon titer of 160-320 IU/ml was observed 18 hours after the drug administration in a dose of 12.5 mg/kg. In low doses of 5 to 12.5 mg/kg bonafton increased the nonspecific resistance of the mice to experimental viral infections when administered orally in single doses not earlier than 2 weeks prior to the contamination. The ability of the drug to stimulate the host protective forces probably plays a certain role in the mechanism of its therapeutic action in severe viral infections of man such as severe recurring ophthalmic herpes, genital herpes, Beh?et's disease, Melkersson-Rosenthal syndrome and others.     

Evidence indicating participation of the serotonergic system in controlling feeding behavior in Coturnix japonica (Galliformes: Aves).

We investigated participation of the brain serotonergic system in food intake control by using oral and systemic administration of serotonin precursors in quails (Coturnix japonica). Dietary supplemental tryptophan (0.1-50.0 g/kg) provoked a dose-dependent inhibition of food intake during a 5-h observation period, which persisted up to 24 h for doses of 30.0 and 50.0 g/kg. Normally fed and fasted animals treated with hydroxytryptophan (12.5-50.0 mg/kg) by the intracoelomic route showed an acute inhibition of food intake. Hypophagia in fasted birds was only effective when the precursor was administered immediately before food presentation. A similar response was obtained by administering serotonin (0.125-2.5 mg/kg, sc), with animals showing a hypnogenic response within the first ten minutes after administration, suggesting that, in contrast to mammals, the amine crosses the blood-brain barrier in quails. Administration of hydroxytryptophan at all doses tested induced significant dipsogenic behavior despite the concomitant hypnogenic response. The results suggest the involvement of serotonergic pathways in food intake control in quails and also show, for the first time, hypnogenic action induced by serotonin and a hyperdipsic effect elicited by hydroxytryptophan.     

Differentiation of beta-adrenoceptors in right atrium, diaphragm and adipose tissue of the rat, using stereoisomers of propranolol, alprenolol, nifenalol and practolol.

2-Diazomorphine-bovine serum albumin (2-DAM-BSA) was prepared by diazotizing p-aminobenzoyl-BSA to morphine. Rabbits immunized with 2-DAM-BSA produced antibodies directed to morphine. A 50 percent reduction in ³H-morphine binding required 4.4 pmol of morphine, and 60, 225, and 350 pmol of normorphine, morphine-3-glucuronide, and codeine, respectively. A radioimmunoassay for brain morphine is described, validated, and used to determine if naloxone alters brain morphine in morphine pelleted mice. The apparent biological half-life of morphine in brain was approximately 52 hours between 24 and 72 hours after pellet implantation, and decreased to 1.25 hours after pellet removal. Naloxone (10 mg/kg) administered 24, 48, or 72 hours after implantation and in doses of 1.0–100 mg/kg administered at 48 hours resulted in either no significant change, or, in a few experiments, increased the brain concentration of morphine. The present experiments could not detect a fraction of total brain morphine that is reduced by naloxone.