Twenty-Four-Hour Patterns of Pineal Melatonin and Pituitary and Plasma Prolactin in Male Rats under ‘Natural’ and Artificial Lighting Conditions

1988 ◽  
Vol 48 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Maija-Liisa Laakso ◽  
Tarja Porkka-Heiskanen ◽  
Aino Alila ◽  
Mikael Peder ◽  
Gunnar Johansson
Keyword(s):  
Male Rats ◽  
Plasma Prolactin ◽  
Artificial Lighting ◽  
Pineal Melatonin ◽  
Lighting Conditions

Daily illuminance levels affect pituitary prolactin in male rats

1989 ◽  
Vol 120 (4) ◽  
pp. 429-434 ◽  
Author(s):  
Maija-Liisa Laakso ◽  
Tarja Porkka-Heiskanen ◽  
Aino Alila ◽  
Susanna Kajander ◽  
Dag Stenberg ◽  
...  
Keyword(s):  
Serum Levels ◽  
Causative Factor ◽  
Male Rats ◽  
Adaptation Period ◽  
Artificial Lighting ◽  
Natural Lighting ◽  
Lighting Conditions ◽  
Illuminance Level ◽  
Pituitary Prolactin

Abstract. The 24-h patterns of melatonin, PRL, and gonadotropins in male rats maintained under natural lighting conditions have been found to differ from the patterns in rats kept under artificial lighting. In the present experiments we studied the role of different daily illuminances as a possible causative factor for the variation of the hormonal patterns. Three groups of male rats were kept under artificial lighting conditions (12 h on/12 h off), where the daily illuminance was 550, 110 or 25 lux. After a 7-day adaptation period the pineal content of melatonin, the serum levels of LH, FSH and PRL, and the pituitary content of these hormones were measured by RIAs in samples taken at 10.00, 13.00, 22.00 and 01.00 h. The patterns of pineal melatonin were equal in all three groups. The variation of daily illuminance did not change the serum levels of LH, FSH and PRL or the pituitary content of the gonadotropins. However, the pituitary content of PRL during the light phase was inversely related to the illuminance. The results suggest that the intensity of daily lighting in the studied range does not affect the patterns of melatonin or gonadotropins, but the synthesis of prolactin may be significantly regulated by the daily illuminance level.

Errors of In Situ Illuminance Measurements

2016 ◽  
Vol 824 ◽  
pp. 676-683
Author(s):  
Michaela Hlásková ◽  
Lenka Gábrová ◽  
František Vajkay
Keyword(s):  
Measurement Errors ◽  
Daily Basis ◽  
Lighting Design ◽  
Public Health Authority ◽  
Construction Work ◽  
Measurement Instruments ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Overcast Sky

Lighting conditions in buildings are verified by experts on a daily basis. Such verifications may be done at several phases in various ways. In the field of daylighting, it is common to make an assessment within the pre-design and in-design phases of a construction work throughout calculations, only rarely by measurements. This approach is the opposite of artificial lighting design, which is done within the in-design phase by calculations and is verified by measurements in post-realization phase. The verification of artificial lighting design is required by the building and public health authority otherwise buildings cannot be approved to use. In the field of daylighting, measurements could be performed as well, nevertheless those are often problematic because regulations usually require fulfilments of the daylight factor which can be determined only under CIE overcast sky. Howbeit, both artificial lighting and daylighting measurements are influenced by many errors, e.g. errors of light measurement instruments, measurement conditions, measurement methods and human factor. The paper is focused on this aspect of lighting design, more specifically on the daylighting measurement errors.

scholarly journals Aberrant Lighting Causes Anxiety-like Behavior in Mice but Curcumin Ameliorates the Symptoms

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2590
Author(s):  
Dhondup Namgyal ◽  
Kumari Chandan ◽  
Sher Ali ◽  
Ajaz Ahmad ◽  
Maha J. Hashim ◽  
...  
Keyword(s):  
Body Weight ◽  
Research Field ◽  
The Body ◽  
Laboratory Animals ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Daily Food ◽  
Significant Difference ◽  
Negative Effect ◽  
Lighting Systems

In the modern research field, laboratory animals are constantly kept under artificial lighting conditions. However, recent studies have shown the effect of artificial light on animal behavior and metabolism. In the present study on mice, following three weeks of housing in dim light at night (dLAN; 5lux) and complete darkness (DD; 0lux), we monitored the effect on body weight, daily food intake, anxiety-like behavior by employing the open field test, and expression of the period (PER1) gene. We also studied the effect of oral administration of different concentrations of curcumin (50, 100, and 150 mg/kg) for three weeks in the same mice and monitored these parameters. The exposure to dLAN had significantly increased the anxiety-like behavior and body weight possibly through the altered metabolism in mice, whereas exposure to DD caused increased anxiety but no significant difference in weight gain. Moreover, the expression of the PER1 gene involved in sleep was also found to be decreased in the aberrant light conditions (dLAN and DD). Although the treatment of curcumin had no effect on body weight, it ameliorated the anxiety-like behavior possibly by modulating the expression of the PER1 gene. Thus, alteration in the light/dark cycle had a negative effect on laboratory animals on the body weight and emotions of animals. The present study identifies the risk factors associated with artificial lighting systems on the behavior of laboratory animals and the ameliorative effects of curcumin, with a focus on anxiety-like behavior.

Involvement of physiological prolactin levels in growth and prolactin receptor content of prostate glands and testes in developing male rats

1992 ◽  
Vol 132 (3) ◽  
pp. 449-459 ◽  
Author(s):  
B. Pérez-Villamil ◽  
E. Bordiú ◽  
M. Puente-Cueva
Keyword(s):  
Body Weight ◽  
Male Rats ◽  
Ventral Prostate ◽  
Serum Prolactin ◽  
Plasma Prolactin ◽  
Stages Of Development ◽  
Continuous Increase ◽  
Testosterone Levels ◽  
Testicular Weight

ABSTRACT We have investigated the role of physiological prolactin levels in the development of prepubertal male rats. Prolactin GH and testosterone levels, as well as body, ventral prostate and testicular weight, have been analysed in both control and bromocriptine-treated rats between 21 and 60 days of life. Furthermore the role of prolactin in the regulation of its own receptors has also been studied during the same period. In control rats, prolactin levels showed a prepubertal peak of secretion at 25 days of age. At this time GH and testosterone levels were low and did not show any significant variation. After this age, prolactin levels increased more gradually; determinations of GH showed great variation with low levels in most of the rats and very high values in the other animals; testosterone levels remained low until day 35 after which they increased. Simultaneously with the serum prolactin peak on day 25, a decrease in prolactin-binding capacity of ventral prostate glands, was observed and a maximum rate of body, prostate and testicular weight gain was obtained. Furthermore, in rats with pharmacologically suppressed serum prolactin levels (lower than 1 μg/l), prolactin binding to prostate glands as well as the weight of body, ventral prostate and testes were lower than in control animals. When results were expressed in mg prostate or testes/g body weight, testes from 25-day-old treated rats weighed significantly less than controls. The later stages of development, from days 25 to 60, were characterized by an initial decline in serum prolactin levels at 29 days of age which was followed by a continuous increase until adult values were reached. During this period, prostatic prolactin receptors which were at their lowest value at 33 days of age showed a gradual rise parallel with the observed increase in plasma prolactin levels. When testicular tissue was analysed, no changes in prolactin-binding sites caused by sexual maturation were observed. The present results indicate that physiological prolactin secretion has a specific effect on the normal increase in the prostate, testes and body weight and clearly is also implicated in the regulation of its prostatic receptors at the earlier stages of development. Journal of Endocrinology (1992) 132, 449–459

Electric field exposure alters serum melatonin but not pineal melatonin synthesis in male rats

1994 ◽  
Vol 15 (5) ◽  
pp. 427-437 ◽  
Author(s):  
L. J. Grota ◽  
R. J. Reiter ◽  
P. Keng ◽  
S. Michaelson
Keyword(s):  
Electric Field ◽  
Male Rats ◽  
Field Exposure ◽  
Pineal Melatonin ◽  
Melatonin Synthesis

Influence of Melatonin and Linseed Oil on the State of Lipid Metabolism at Desynchronosis in Rats

2021 ◽  
pp. 58-68
Author(s):  
Irina S. Sobolevskaya ◽  
◽  
Oleg D. Myadelets ◽  
Natalʼya N. Yarotskaya
Keyword(s):  
Lipid Metabolism ◽  
Linseed Oil ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Atherogenic Index ◽  
Male Rats ◽  
Serum Concentrations ◽  
Rat Serum ◽  
Lighting Conditions

The purpose of this study was to substantiate the possibility of correcting lipid metabolism changes at dark deprivation using linseed oil, melatonin, and their combination. Materials and methods. The experiment involved 130 white outbred male rats with a body weight of 170–220 g. The animals were divided into 5 groups: rats under standard fixed lighting conditions (12 hours light/12 hours dark); rats under modelled dark deprivation with round-the-clock lighting (24 hours light); rats under modelled dark deprivation with round-the-clock lighting (24 hours light) receiving intragastric injections of linseed oil, melatonin or their combination from day 1 of the experiment. Serum concentrations of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total phospholipids (TPL) and atherogenic index (AI) were determined. Results. Long-term dark deprivation led to dyslipoproteinemia, which consists in an increase in serum concentrations of TC by a factor of 1.33 (p = 0.0009), TG by a factor of 1.62 (p = 0.013), LDL-C by a factor of 1.2 (p = 0.026) and TPL by a factor of 1.15 (p = 0.0082). The severity of changes in TC, TG, LDL-C, HDL-C and TPL concentrations varied depending on the duration of the experiment. During the use of linseed oil, melatonin or their combination under dark deprivation, the severity of disorders caused by desynchronosis decreased and lipid metabolism in rat serum normalized, especially at the initial stages of the research. Conclusion. Changes in lipid metabolism due to desynchronosis in rats injected with the substances under study were significantly smaller compared with animals that did not receive them. The most pronounced effects of administering these substances were observed in the group of rats treated with linseed oil and melatonin at the same time.

scholarly journals Constant lighting conditions affect sexual behaviour and hormone levels in adult male rats

Reproduction ◽  
1984 ◽  
Vol 72 (2) ◽  
pp. 435-441 ◽  
Author(s):  
B. D. Fantie ◽  
R. E. Brown ◽  
W. H. Moger
Keyword(s):  
Adult Male ◽  
Sexual Behaviour ◽  
Male Rats ◽  
Hormone Levels ◽  
Lighting Conditions

scholarly journals A Contrast-Guided Approach for the Enhancement of Low-Lighting Underwater Images

2019 ◽  
Vol 5 (10) ◽  
pp. 79 ◽  
Author(s):  
Tunai Porto Marques ◽  
Alexandra Branzan Albu ◽  
Maia Hoeberechts
Keyword(s):  
Automated Analysis ◽  
Local Contrast ◽  
Single Image ◽  
Image Dehazing ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Underwater Image ◽  
Low Visibility ◽  
Contrast Information ◽  
New Framework

Underwater images are often acquired in sub-optimal lighting conditions, in particular at profound depths where the absence of natural light demands the use of artificial lighting. Low-lighting images impose a challenge for both manual and automated analysis, since regions of interest can have low visibility. A new framework capable of significantly enhancing these images is proposed in this article. The framework is based on a novel dehazing mechanism that considers local contrast information in the input images, and offers a solution to three common disadvantages of current single image dehazing methods: oversaturation of radiance, lack of scale-invariance and creation of halos. A novel low-lighting underwater image dataset, OceanDark, is introduced to assist in the development and evaluation of the proposed framework. Experimental results and a comparison with other underwater-specific image enhancement methods show that the proposed framework can be used for significantly improving the visibility in low-lighting underwater images of different scales, without creating undesired dehazing artifacts.

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