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  • 1
    Electronic Resource
    Electronic Resource
    Circadian rhythmicity in the methylation of 5-hydroxy-indoles and norepinephrine in the pineal gland of 10 day old rats (1978)
    Springer
    Journal of neural transmission 43 (1978), S. 167-175 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01579076
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  • 2
    Electronic Resource
    Electronic Resource
    Influence of some pteridines on pineal 5-methoxy-indole synthesis in male wistar rats periodically exposed to either white or red light (1983)
    Springer
    Journal of neural transmission 56 (1983), S. 199-210 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01243278
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  • 3
    Electronic Resource
    Electronic Resource
    The influence of some pteridines on pineal 5-methoxyindole synthesis in male Wistar rats periodically exposed to either white or green light (1983)
    Springer
    Journal of neural transmission 58 (1983), S. 121-134 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01249130
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  • 4
    Electronic Resource
    Electronic Resource
    Day/night rhythmicity in the methylating capacities for different 5-hydroxyindoles in the pineal, the retina and the Harderian gland of the golden hamster (Mesocricetus auratus) during the annual seasons (1983)
    Springer
    Journal of neural transmission 56 (1983), S. 53-72 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01243374
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  • 5
    Electronic Resource
    Electronic Resource
    Preliminary investigations on melatonin and 5-methoxytryptophol synthesis in the pineal, retina, and Harderian gland of the mole rat and in the pineal of the mouse “eyeless” (1980)
    Springer
    Journal of neural transmission 49 (1980), S. 247-255 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01252129
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in the circadian rhythmicity of N- and O-acetyltransferase activities in the pineal gland of 38 day old male Wistar rats when examined under white, red and green light (1981)
    Springer
    Journal of neural transmission 52 (1981), S. 83-93 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01253100
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  • 7
    Electronic Resource
    Electronic Resource
    Seasonal variations in HIOMT activity during the night in the pineal gland of 21 day old male wistar rats (1980)
    Springer
    Journal of neural transmission 49 (1980), S. 107-116 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01249192
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of melatonin and other indole derivatives in maintaining ovulation in rats kept in continuous light and the influence of these indoles on HIOMT activity in the pineal gland (1982)
    Springer
    Journal of neural transmission 53 (1982), S. 305-314 
    Details
    ISSN: 1435-1463
    Keywords: Pineal gland ; continuous light ; ovulation ; indoles ; melatonin ; HIOMT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to investigate whether the ovulation-maintaining effect of melatonin in rats, exposed to continuous light (LL), was also exerted by other pineal indoles which have been reported to influence the reproductive processes of mammals. The effect of 10μg melatonin was compared with that of similar amounts of either N-acetylserotonin, 5-methoxytryptophol, 5-methoxyindole-3-acetic acid, 5-hydroxytryptophol, 5-methoxytryptamine or 5-methoxytryptophan. All these compounds appeared to be significantly less effective than melatonin in preventing the effect of LL, ovulation being preserved in only 20–33 % of the rats investigated, with melatonin this percentage being 60–75%. Investigations were also carried out to assess the effect of these indole derivatives on HIOMT (hydroxyindole-O-methyl transferase) activity in synthesizing different 5-methoxyindoles in the abnormally influenced pineal gland due to LL. Melatonin, the compound the effect of which on ovarian cyclicity is strongest, stimulates 5-methoxytryptophol synthesis; while other less active compounds stimulate the synthesis of melatonin and inhibit that of O-acetyl-5-methoxytryptophol. The possibility that the effect of other indoles than melatonin on ovarian cyclicity might be due to stimulation of melatonin synthesis was considered. A possible functional relationship of the different indoles cannot be excluded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01252041
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  • 9
    Electronic Resource
    Electronic Resource
    The inhibitory effect of 5-methoxytryptophol on ovarian weight, follicular growth and egg production of adult white leghorn hens (Gallus domesticus L.) (1973)
    Springer
    Journal of neural transmission 34 (1973), S. 159-169 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01244669
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  • 10
    Electronic Resource
    Electronic Resource
    Age-dependent effects of 5-methoxytryptophol and melatonin on testes and comb growth of the white leghorn (Gallus Domesticus L.) (1972)
    Springer
    Journal of neural transmission 33 (1972), S. 179-194 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01245316
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