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  • Articles: DFG German National Licenses  (10)
  • Pineal  (10)
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  • Articles: DFG German National Licenses  (10)
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Years
  • 1
    ISSN: 1435-1463
    Keywords: Pineal ; HIOMT ; COMT ; rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In pineals of 10 day old rats 5-hydroxytryptophan, 5-hydroxyindole-3-acetic acid, N-acetylserotonin/5-hydroxytryptophol and norepinephrine are methylated following a circadian rhythm. During the night HIOMT and COMT activities were measured for the above mentioned substrates, while HIOMT activity for 5-hydroxytryptophan and N-acetylserotonin/5-hydroxytryptophol was also determined during daytime.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1435-1463
    Keywords: Pineal ; melatonin/5-methoxytryptophol ; 5-methoxyindoles ; pteridines ; red light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In previous investigations the change of circadian rhythmicity in pineal melatonin/5-methoxytryptophol synthesis of rats periodically exposed to red light was similar to that in pineals of rats incubated with pterin-6-aldehyde. These experiments were, however, performed with rats of different age and in different periods of the year. In the present study these two factors influencing pineal indole metabolism have been combined the experiments being carried out in rats aged 28 days and during the same day in the month of January. It was observed that under influence of red light the peak of melatonin/5-methoxytryptophol synthesis shifted towards daytime, whereas incubation with pterin-6-aldehyde did not cause such a shift. If under different experimental conditions the mean amount of melatonin/5-methoxytryptophol which was formed over a 24 hour period was compared, it appeared that pineals of rats exposed to white light incubated with reduced neopterin but not pineals incubated with pterin-6-aldehyde behave in this respect similar to pineals of rats exposed to red light. However, if the ratio between melatonin/5-methoxytryptophol and 5-methoxytryptamine is calculated pineals of white light exposed rats incubated in pterin-6-aldehyde behaved very similar to the pineals of rats exposed to red light. Although the role of pteridines remains obscure, it appears that the parameters 1. circadian rhythmicity and 2. the amount of 5-methoxyindoles and 3. the ratio between these indole derivatives might be of importance in analyzing their physiological effects. The influence of application of light of different wavelenghts and year rhythmicity is discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1463
    Keywords: Pineal ; melatonin/5-methoxytryptophol ; 5-methoxyindoles ; pteridines ; green light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pineals of 28 days old male Wistar rats, in December periodically exposed to either white or green light, were incubated with pterin-6-aldehyde or reduced neopterin. In white light the rhythm of synthesis of 5-methoxytryptophan and of 5-methoxyindole-3-acetic acid was clearly influenced by the pteridines mentioned. In green light a change in rhythmicity of 5-methoxytryptophan, 5-methoxytryptamine and of melatonin/5-methoxytryptophol synthesis by the pteridines was observed. In white light both pteridines increased 5-methoxytryptophan and decreased 5-methoxyindole-3-acetic acid synthesis. Reduced neopterin stimulated 5-methoxytryptamine synthesis and inhibited melatonin/5-methoxytryptophol synthesis. Pterin-6-aldehyde showed an opposite effect. In green light both pteridines decreased 5-methoxytryptophan synthesis, but increased 5-methoxyindole-3-acetic acid and 5-methoxytryptamine synthesis. Melatonin/5-methoxytryptophol synthesis was decreased by reduced neopterin and increased by pterin-6-aldehyde. The results suggest an indolic metabolic pathway leading from 5-methoxytryptophan via 5-methoxytryptamine to melatonin, while pteridines and light of different wave lengths are correlated in regulating indole metabolism.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1463
    Keywords: Pineal ; retina ; Harderian gland ; methoxyindoles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the pineal, the Harderian gland and the retina of the golden hamster the day/night capacity for the synthesis of different methoxyindoles is investigated under natural conditions for one 24-hour period in the months of December, March and June. The amounts of the methoxyindoles and the diurnal rhythms in the synthesis are different in the various months during which the tests were performed. There is a striking increase in the synthesis of melatonin and methoxytryptophol in all three organs in June as compared with December. Equally striking is the high synthesis of methoxytryptamine in the pineal in June, whereas this compound was not formed in the Harderian gland and the retina in this month. Methoxytryptophan synthesis was not observed in June in any of the three organs. Methoxyindoleacetic acid rhythmicity shows a pattern more or less identical to that of melatonin and methoxytryptophol. A high synthesis exists at the end of the June day, but greater fluctuations during the days of the two other months. Acetylmethoxytryptophol is synthesized in the pineal during the night in March, but in the late afternoon in June. The largest quantity of this compound is found in the Harderian gland in December, in the pineal in March and in the retina in June. The largest amounts of melatonin and methoxytryptophol are synthesized when gonadal weight is largest. The possible correlation between the amounts synthesized, the rhythmicities in synthesis and the reproductive system is discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1435-1463
    Keywords: Pineal ; retina ; Harderian gland ; HIOMT ; melatonin ; 5-methoxytryptophol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hydroxyindole-O-methyltransferase (HIOMT) activity for the synthesis of melatonin and 5-methoxytryptophol, both 5-methoxyindoles, was measured in the pineal, the Harderian gland and the retina of the mole rat and in the pineal of the mouse “eyeless”. In the pineal and the Harderian gland of the mole rat a larger amount of 5-methoxytryptophol than of melatonin is synthesized. 5-Methoxyindole synthesis is extremely high in the Harderian gland, whereas in the retina HIOMT activity is low and variable. In the pineal of the mouse “eyeless”, a low 5-methoxyindole synthesis showing no circadian rhythm is demonstrated. It is concluded that, besides the generally accepted regulation of the indole metabolism by light, in species with atrophied eyes having Harderian glands (mole rat) and in species without eyes other factors than light might be responsible for the indole metabolism in the pineal gland.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1435-1463
    Keywords: Pineal ; N-acetyltransferase ; O-acetyltransferase ; circadian rhythmicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary N-acetyltransferase activity was quantified in the pineal gland of 38 day-old male Wistar rats under different experimental conditions. Under daily white light/dark photoperiods (12 L∶12 D), N-acetyltransferase activity showed a peak of activity at midnight for the synthesis of both N-acetylserotonin and melatonin. Using red light instead of white light a shift of the enzyme activity involved in the production of both compounds towards the preceding light period was observed. Using green light instead of white light the enzyme activity shifted to later periods. Under white light/dark conditions pineal O-acetyltransferase activity when quantified was maximal during the early hours of the night. With periodic red light this maximal activity was extended over a longer period including late hours of the preceding day and later hours of the night. Periodic illumination with green light caused a peak of activity at midnight and an increase of activity at the end of the dark period. A possible relationship between previous results obtained on the influence of pterins on HIOMT activity and the effects of light on reproduction is discussed.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1435-1463
    Keywords: Pineal ; HIOMT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the pineal of 21-day old male Wistar rats hydroxyindole-O-methyl-transferase (HIOMT) activities involved in the synthesis of several 5-methoxyindoles were determined during the night in April, June, October and January. A high HIOMT activity for the synthesis of melatonin/5-methoxytryptophol was determined in the months of January and April. In June and October a decrease was observed. The activity maxima coincide with peaks of activity found for the synthesis of 5-methoxytryptophan. Synthesis of 5-methoxytryptamine occurred only in June and October, whereas the synthesis of 5-methoxyindole-3-acetic acid occurred only in January. From these results it may be concluded that January and April are the most active months of those tested for the melatonin/5-methoxytryptophol synthesis in the rat pineal gland. A possible physiological role of the 5-methoxyindoles other than melatonin and 5-methoxytryptophol is discussed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1435-1463
    Keywords: Pineal ; indoles ; gonads ; chick
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Identical age, body weight, or initial comb size are not useful as parameters in analysing effects of pineal substances on the gonadal system of adult white leghorn hens. A combination, however, of the initial comb size with the frequency of oviposition proved to be an adequate parameter. Administration of 5-methoxytryptophol in increasing concentrations to adult hens shows an inhibitory effect on ovarian and follicular weight. This effect is not only realized by a decrease in organ weight, but also by a retardation of the rhythm as expressed in initial comb size units. As follicular growth is mainly dependent on a FSH/LH ratio in which the LH content is increased, the inhibitory effect may possibly be described to this relation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 33 (1972), S. 179-194 
    ISSN: 1435-1463
    Keywords: Pineal ; indoles ; gonads
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Testes weights of white leghorns of the same age or of equal body weight vary considerably. Experiments on the effects of pinealectomy, administration of pineal extracts or indolic compounds on the testes weights therefore require better parameters. Cockerels having a similar initial comb size prove to have testes of similar weights. Experiments using this parameter permit a more exact comparison of control and experimental animals. Administration of 5-methoxytryptophol and melatonin in increasing concentrations to juvenile, maturing and adult white leghorn males shows an age-dependent activity. In juvenile birds, the testes and comb growth are stimulated by 5-methoxytryptophol and melatonin, whereas in maturing and adult cocks both indolic compounds show an inhibitory effect. It appears that the effect of 5-methoxytryptophol is more specific than that of melatonin in juvenile as well as in maturing and adult white leghorns.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neural transmission 34 (1973), S. 49-60 
    ISSN: 1435-1463
    Keywords: Pineal ; indoles ; gonads ; chick
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Concerning the gonads, the initial comb size in white leghorn cockerels proved to be a parameter which permits a more exact comparison of control and experimental animals, than the generally used parameters of identical age and/or body weight. As in literature contradictory results are described after injecting different concentrations of 5-methoxyindoles, it may be possible that these results can be explained by the parameters used. To analyse this, several concentrations of 5-methoxytryptophol were injected in increasing amounts in white leghorn cockerels, using the comb size as a parameter. In all experiments a stimulatory effect of 5-methoxytryptophol on testicular weight was observed. Administration of the smallest concentrations (0.1–3.5μg, exp. I, and 1.0–35μg, exp. II) showed an acceleration of the growing rhythm of the testes if compared with the control animals. With the comb size as a parameter it was possible to analyse the degree of stimulation in comb size units. Administration of 2.5–87.5μg (exp. III) and of 10–350μg (exp. IV) of 5-methoxytryptophol resulted also in a stimulatory activity on testicular growth; acceleration of the growing rhythm, however, now proved to be irregular and could not be compared with the growing pattern of the testes in the control animals.
    Type of Medium: Electronic Resource
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