Thymidine incorporation by cultured chick pineal glands is not subject to adrenergic regulation

1990 ◽  
Vol 68 (1) ◽  
pp. 145-147 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Pineal Gland ◽  
Thymidine Incorporation ◽  
Adrenergic Regulation ◽  
Acetyltransferase Activity

Norepinephrine is known to play a role in regulating the circadian rhythms of serotonin N-acetyltransferase activity and melatonin formation in the chick pineal gland. We have recently demonstrated that the cultured chick pineal exhibits a circadian rhythm in the incorporation of thymidine. In this study we show that this latter rhythm is not subject to adrenergic control.Key words: chick, pineal gland, thymidine incorporation, adrenergic regulation.

Circadian rhythms of enzyme and running activity under ultradian lighting schedule.

1977 ◽  
Vol 232 (4) ◽  
pp. E375
Author(s):  
T Deguchi
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Pineal Gland ◽  
Dark Period ◽  
Foster Mother ◽  
Lighting Condition ◽  
Acetyltransferase Activity ◽  
Lighting Conditions ◽  
Running Activity ◽  
Circadian Change

Serotonin N-acetyltransferase activity in the pineal gland and running acitvity of rats were measured under an ultradian lighting schedule (light/dark 6:6). When rats were moved from a diurnal lighting condition to the ultradian conditions, N-acetyltransferase activity showed a circadian rhythm, increasing once a day. N-acetyltransferase activity in the pups born and raised under the ultradian lighting conditions also exhibited a circadian change, the phase of which coincided with that of their mothers. When pups were raised by a foster mother with an inverted rhythmic phase from that of the original mother, the phase of the rhythm in N-acetyltransferase activity of the pups synchronized with that of the foster mother. When pups were separated from their mothers for 12 h/day, the circadian increase of N-acetyltransferase activity appeared during the dark period when they were separated from their mothers. The circadian rhythms of running acitvity were in phase with those of N-acetyltransferase activity in the pineal gland.

scholarly journals Increase in 6-Hydroxymelatonin Excretion in Humans during Ascent to High Altitudes

2004 ◽  
Vol 89 (9) ◽  
pp. 4388-4390 ◽  
Author(s):  
Herwig Frisch ◽  
Franz Waldhauser ◽  
Thomas Waldhör ◽  
Andrea Müllner-Eidenböck ◽  
Pritam Neupane ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Pineal Gland ◽  
Diurnal Variation ◽  
Healthy Volunteers ◽  
High Altitude ◽  
Physiological Role ◽  
Physiological Significance ◽  
High Altitudes ◽  
Lower Altitude

Melatonin (MLT), the pineal gland hormone involved in the regulation of circadian rhythms, shows characteristic diurnal variation. Its physiological role in humans is not clear. Exposure to high altitudes may disrupt the circadian rhythm and lead to various endocrine changes. MLT in humans has not been studied under these conditions. Urinary 6-hydroxy-MLT sulfate (aMT6s) excretion was analyzed during the day (0700–2200 h) and night (2200–0700 h) phases. A cohort of 33 healthy volunteers, aged 19–65 yr, was studied during an ascent to a high altitude in the Himalayas on three occasions (at a lower altitude, at 3400 m, and after reaching maximal altitudes of 5600–6100 m). aMT6s excretion during the daytime remained unchanged during exposure to high altitudes. As expected, nocturnal values were higher than diurnal values at each point in time. However, there was a significant increase in nocturnal MLT excretion after the ascent to high altitudes. Ascent to high altitudes is associated with increased nocturnal excretion of aMT6s. The mechanism and physiological significance of this MLT increase are unclear.

Pineal gland

2018 ◽  
pp. 130-133
Author(s):  
Helen E. Turner ◽  
Richard Eastell ◽  
Ashley Grossman
Keyword(s):  
Circadian Rhythm ◽  
Clinical Practice ◽  
Circadian Rhythms ◽  
Pineal Gland ◽  
Mammalian Cell ◽  
Photoreceptor Cells ◽  
Secretory Function ◽  
Seasonal Rhythms ◽  
The Third ◽  
Therapeutic Benefits

This chapter describes the pineal gland’s structure, related hormones, and physiology. The pineal gland (epiphysis cerebri) is a small (100–150 mg in humans), unpaired central structure. The mammalian pineal is a secretory organ, whereas in fish and amphibians it is directly photoreceptive (the ‘third eye’) and in reptiles and birds it has a mixed photoreceptor and secretory function. The main mammalian cell type is the pinealocyte, considered to have evolved from photoreceptor cells. This chapter discusses melatonin’s metabolism, and the pineal gland’s function in seasonal rhythms and circadian rhythms. It discusses pineal gland-related pathology, including tumours and cancer. The chapter also discusses the use of melatonin, in clinical practice, describing the hormone’s therapeutic benefits in circadian rhythm disorders.

scholarly journals BMAL1 but not CLOCK is associated with monochromatic green light-induced circadian rhythm of melatonin in chick pinealocytes

2019 ◽  
Vol 8 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Shuhui Ma ◽  
Zixu Wang ◽  
Jing Cao ◽  
Yulan Dong ◽  
Yaoxing Chen
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Pineal Gland ◽  
Clock Genes ◽  
Critical Role ◽  
Green Light ◽  
Circadian Oscillator ◽  
Melatonin Secretion ◽  
Expression Levels

The avian pineal gland, an independent circadian oscillator, receives external photic cues and translates them for the rhythmical synthesis of melatonin. Our previous study found that monochromatic green light could increase the secretion of melatonin and expression of CLOCK and BMAL1 in chick pinealocytes. This study further investigated the role of BMAL1 and CLOCK in monochromatic green light-induced melatonin secretion in chick pinealocytes using siRNAs interference and overexpression techniques. The results showed that si-BMAL1 destroyed the circadian rhythms of AANAT and melatonin, along with the disruption of the expression of all the seven clock genes, except CRY1. Furthermore, overexpression of BMAL1 also disturbed the circadian rhythms of AANAT and melatonin, in addition to causing arrhythmic expression of BMAL1 and CRY1/2, but had no effect on the circadian rhythms of CLOCK, BMAL2 and PER2/3. The knockdown or overexpression of CLOCK had no impact on the circadian rhythms of AANAT, melatonin, BMAL1 and PER2, but it significantly deregulated the circadian rhythms of CLOCK, BMAL2, CRY1/2 and PER3. These results suggested that BMAL1 rather than CLOCK plays a critical role in the regulation of monochromatic green light-induced melatonin rhythm synthesis in chicken pinealocytes. Moreover, both knockdown and overexpression of BMAL1 could change the expression levels of CRY2, it indicated CRY2 may be involved in the BMAL1 pathway by modulating the circadian rhythms of AANAT and melatonin.

Retinal illumination phase shifts the circadian rhythm of serotonin N-acetyltransferase activity in the chicken pineal gland

2004 ◽  
Vol 360 (3) ◽  
pp. 153-156 ◽  
Author(s):  
Jolanta B. Zawilska ◽  
Małgorzata Berezińska ◽  
Anna Lorenc ◽  
Debra J. Skene ◽  
Jerzy Z. Nowak
Keyword(s):  
Circadian Rhythm ◽  
Pineal Gland ◽  
Phase Shifts ◽  
Acetyltransferase Activity
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