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Biomedical subjects

L Wetterberg

Publications and source records attributed to L Wetterberg.

At least 19 recordsLinked to original sources

Reduction of whole blood serotonin in depressed patients treated with a new, selective serotonin-uptake inhibitor, femoxetine.

Femoxetine, a phenylpiperidine derivative with potent serotonin (5-HT)-uptake inhibitory properties, was investigated in 12 depressive patients for its clinical effect as well as its effect on 5-HT concentration in whole blood. The global evaluation after 6 weeks showed a good effect in six patients. The 5-HT concentration was found to be reduced from a mean value of 0.21 to about 0.05 micrograms/ml, indicating a total depletion of 5-HT from the thrombocytes. The steady-state concentrations of femoxetine resulted in reduction of 5-HT to the same level in all patients. No correlation between degree of 5-HT reduction and therapeutic effect was found.

Anisoles

Circadian variation in urinary melatonin in clinically healthy women in Japan and the United States of America.

Urinary melatonin excretion is lower in East-Asian (Japanese) than in North-American (whites of mixed ethnic origin) women. Moreover, a statistically significant circadian rhythm is demonstrated by population-mean cosinor in the data pool from both groups of women. Furthermore, statistical significance characterizes interactions of effects from geographic differences (between ethnic groups) with temporal factors. Such spatio-temporal interactions await further scrutiny with a view inter alia of carcinogenesis as it is influenced by a spectrum of intermodulating rhythms.

Adult

Platelet monoamine oxidase in a pedigree with schizophrenia: an interlaboratory project.

Conflicting reports on the association between platelet MAO activity and schizophrenia prompted a critical review and determinations on identical samples at one laboratory in Sweden and one in the U.S.A. Samples originated from eight schizophrenics and 27 relatives belonging to a large pedigree, thus ensuring biological homogeneity. In the USA laboratory, a significantly lower MAO activity was found in the schizophrenics when benzylamine or beta-phenylethylamine was used as substrate (but not with tryptamine), while a similar result was obtained in the Swedish laboratory when tryptamine was used (but not with benzylamine or beta-phenylethylamine). Comparisons between materials examined in different laboratories do not seem meaningful until differences in methodologies have been clarified. At present there is neither proof nor disproof of MAO being a "genetic marker" for vulnerability to the schizophrenic disorder.

Benzyl Compounds

The influence of early nutrition on growth and the circulating levels of immunoreactive somatomedin A.

The effect of nutrition during early development on growth and serum immunoreactive somatomedin A was examined in rats by rearing in small or large liters. At weaning, body weight, brain weight, liver weight and DNA content was significantly reduced in rats whose nutrition was restricted by rearing in large litters. Brain DNA content was significantly altered. Serum somatomedin A was significantly reduced in the growth-retarded rats as compared to those whose growth was enhanced by rearing in small litters. Similarly, maternal serum somatomedin A was significantly reduced in rats nursing large litters.

Animals

Potent depletion of 5HT from monkey whole blood by a new 5HT uptake inhibitor, paroxetine (FG 7051).

The potent 5-hydroxytryptamine (5HT) uptake inhibitor FG 7051 (paroxetine, INN) was administered to rhesus monkeys in doses of 1.0, 2.5 or 7.5 mg/kg by oral gavage once daily for 13 weeks. Blood samples for analysis of 5HT in whole blood and paroxetine in plasma were taken prior to and after 1, 4 and 13 weeks of treatment. The lowest dose 1 mg/kg caused 30% depletion of 5HT in whole blood with a level of paroxetine in plasma below 2 ng/ml. Doses of 2.5 mg/kg produced an 85% depletion of 5HT and a steady state plasma concentration of about 5 ng paroxetine/ml, while 7.5 mg/kg caused a 93% depletion of 5HT and a steady state plasma concentration of 100--450 ng paroxetine/ml. There was no concentration-dependent 5HT reduction with the highest dose level suggesting that maximal depletion was produced by concentrations below 100 ng/ml. The results showed that paroxetine is a strong depletor of 5HT from whole blood of monkeys conceivably because it inhibits 5HT uptake inhibition. The effect of the drug reached its maximum within 1 week and no tolerance developed during 13 weeks.

Animals

N-Acetyltransferase activity of the rat Harderian gland.

Harderian gland extracts from male rats catalyze the conversion of serotonin to N-acetylserotonin and of tryptamine to N-acetyltryptamine. The reaction is linear up to 14 mg tissue and departs from linearity after 10 min. The pH otpimum with tryptamine as substrate is between 8 and 9. Enzymic activity of the gland in vivo does not show diurnal variations. Enzymic activity of tissue in organ culture is not stimulated by 10 micrometer isoproterenol or 100 micrometer dibutyryl cyclic AMP. Harderian gland tissue in culture can acetylate tryptamine and serotonin and can O-methylate the N-acetylserotonin to form melatonin.

Acetylation

A simplified radioimmunoassay for melatonin and its application to biological fluids. Preliminary observations on the half-life of plasma melatonin in man.

A simplified and rapid radioimmunoassay (RIA) for melatonin is presented. Melatonin is extracted from seru, plasma or urine and RIA is performed by using [3H]melatonin as the tracer. The standard curve covers the range 0.2--4.3 nmol/l. By increasing the sample volume the range can be extended to 0.06 nmol/l. The intra-assay variability is 7% (relative standard deviation = rsd) and the inter-assay variability is 10% (rsd). The recovery of melatonin added to calf serum is 96%. The long term variability of the assay (43 assays on aliquots of one serum sample during 6 months) is 13.5% (rsd). The serum levels in man after one oral dose of 430 mumol melatonin have been measured. The peak value, 620 nmol/l, was noted after 0.5 h and the melatonin concentration was still above the normal range at 24 h (2.1 nmol/l).

Growth Hormone

Dense plexus of substance P immunoreactive nerve terminals in eminentia medialis of the primate hypothalamus.

The indirect immunofluorescence technique of Coons and collaborators was used to study the distribution of substance P-like and luliberin (luteinizing hormone-releasing hormone)-like immunoreactivity in the eminentia mediana (eminentia medialis or infundibulum) of rats, monkeys, and human beings. In rats, abundant luliberin-positive fibers were present in the external layer (mainly lateral parts) whereas almost no substance P-immunoreactive nerves were observed in this region. In contrast, in the external layer of the primate eminentia medialis a dense plexus of substance P-positive nerve terminals was observed close to the blood vessels supplying the anterior pituitary gland. Luliberin-immunoreactive fibers were also present, but with a more even distribution all over the eminentia medialis and in lower numbers. The present findings indicate that substance P may play a role in the control of hormone secretion from the anterior pituitary, either by being released into the portal vessels, i.e., acting as a releasing or inhibitory hormone, or by an action as local regulator (modulator or transmitter) at the level of the eminentia medialis. Thus, in agreement with many earlier studies, substances other than the "classical" releasing and inhibitory hormones may be important for the regulation of the pituitary gland. Furthermore, there may exist marked species differences with regard to the type of substances involved in the central control of the pituitary.

Animals