CIRCADIAN RHYTHM OF PINEAL UPTAKE OF 32P IN DOMESTIC FOWL

1977 ◽  
Vol 73 (1) ◽  
pp. 99-103 ◽  
Author(s):  
J. W. SACKMAN
Keyword(s):  
Circadian Rhythm ◽  
Pineal Gland ◽  
Domestic Fowl ◽  
Gallus Domesticus ◽  
Dark Phase ◽  
White Leghorn ◽  
Light Phase ◽  
Radioactive Phosphorus ◽  
Light:Dark Cycle ◽  
Constant Dark

SUMMARY The uptake of radioactive phosphorus by the pineal gland in White Leghorn cockerels (Gallus domesticus) showed a diurnal variation with maxima in the light phase and minima in the dark phase of the light:dark cycle. Constant light caused the rhythm to disappear while constant dark had no effect other than lowering the amplitude of the variations. These data indicate that the rhythm in pineal uptake of 32P is circadian.

scholarly journals Heterosis and Selection in the Domestic Fowl

1966 ◽  
Vol 19 (4) ◽  
pp. 575 ◽  
Author(s):  
JA Morris ◽  
FE Binet
Keyword(s):  
Domestic Fowl ◽  
Selection Criterion ◽  
Inbred Strains ◽  
Gallus Domesticus ◽  
Hybrid Vigour ◽  
White Leghorn ◽  
Parental Lines

Hybrids, generated by crossing highly selected and mildly inbred strains from two distinct breeds (viz. Australorp and White Leghorn) of Gallus domesticus, showed appreciable hybrid vigour with respect to the trait used in the parental lines as selection criterion, and also with respect to certain other traits.

scholarly journals Cyclophosphamide Depletes Ovarian Follicles in Mice During Both the Light and Dark Phases of the Circadian Cycle

2020 ◽  
Vol 17 (3) ◽  
pp. 11-17
Author(s):  
Benjamin Koch ◽  
Kristen Roosa
Keyword(s):  
Circadian Rhythm ◽  
Ovarian Reserve ◽  
Alkylating Agent ◽  
Single Injection ◽  
Ovarian Follicles ◽  
Dark Phase ◽  
Light Phase ◽  
Primordial Follicles ◽  
Ovarian Toxicity ◽  
The Impact

The alkylating agent cyclophosphamide (CY) is a potent ovarian toxicant. It damages growing follicles and causes premature activation and depletion of the resting follicles that constitute the ovarian reserve. While there is abundant information on the impact of CY on the ovary and its toxicity mechanisms, the influence of the circadian rhythm on ovarian toxicity has not been evaluated. To test the hypothesis that time of exposure affects ovarian toxicity of CY, C57BL/6 mice were treated with a single injection of CY (75 mg/kg) at either two hours after lights on (Zeitgeber time (ZT) 02) or two hours after lights off (ZT14). Toxicity was evaluated one week after treatment by counting ovarian follicles in histological sections. Fewer primordial follicles were counted in the ovaries of CY-treated animals at both treatment times, and fewer antral follicles were counted in the ovaries of animals treated at ZT02. There was no difference in the number of primordial follicles in the ovaries of CY-treated animals between the two treatment times. These results demonstrate that CY-induced depletion of the ovarian reserve occurs when mice are exposed early in the light phase and early in the circadian cycle’s dark phase. There is no impact of the circadian rhythm on follicle depletion by CY at these time points. KEYWORDS: Cyclophosphamide; ovary; circadian; ovarian follicles; toxicity; mouse; chronotherapy; alkylating agent

The influence of lighting conditions upon the level and course of increase in specific activity of serotonin N-acetyltransferase in the developing chick pineal gland

1976 ◽  
Vol 54 (2) ◽  
pp. 103-109 ◽  
Author(s):  
I. H. Fraser ◽  
S. D. Wainwright
Keyword(s):  
Pineal Gland ◽  
Specific Activity ◽  
Major Product ◽  
Constant Darkness ◽  
Dark Phase ◽  
Light Phase ◽  
Normal Cycle ◽  
Lighting Conditions ◽  
Hydroxyindoleacetic Acid ◽  
Unidentified Metabolite

A diurnal cycle in level of serotonin acetyltransferase (acetyl-CoA: arylamine N-acetyltransferase (EC 2.3.1.5)) activity was found in the pineal gland of chicks aged 16 to 20 days maintained under diurnal lighting conditions. Diurnal variation in levels of activity was markedly reduced in the pineal gland of birds kept in constant darkness, and suppressed in the gland of chicks under constant illumination. High levels of activity attained during the dark phase of the normal cycle rapidly declined when the birds were transferred to the light. The light phase level of serotonin acetyltransferase of the pineal increased progressively from the 11th day of incubation to about 1 week post-hatch. This course of increase in enzyme activity was largely unaffected by lighting conditions. Under conditions for assay of serotonin acetyltransferase activity in the chick pineal gland and brain, radioactive serotonin gave rise to N-acetylserotonin, 5-hydroxyindoleacetic acid and a further unidentified metabolite, which was quantitatively the major product.

Abnormalities in the plasma concentrations of thyroxine, tri-iodothyronine and growth hormone in sex-linked dwarf and autosomal dwarf White Leghorn domestic fowl (Gallus domesticus)

1983 ◽  
Vol 97 (1) ◽  
pp. 127-135 ◽  
Author(s):  
C. G. Scanes ◽  
James Marsh ◽  
Eddy Decuypere ◽  
Peter Rudas
Keyword(s):  
Domestic Fowl ◽  
Autosomal Recessive ◽  
Plasma Concentrations ◽  
Causative Factor ◽  
Gallus Domesticus ◽  
Control Strain ◽  
White Leghorn ◽  
Age Related ◽  
Plasma Hormone ◽  
Dwarf Chicken

Plasma concentrations of GH were high in young birds (2–12 weeks old) and low in older birds (15 and 18 weeks old) in the control Cornell K strain of White Leghorn fowl. There was little variation in the plasma concentrations of tri-iodothyronine (T3) and thyroxine (T4) with age in this strain. Similar patterns of plasma hormone concentrations with age were observed in autosomal recessive dwarf chickens. However, the plasma concentrations of T3 and T4 tended to be depressed while that of GH was raised. There was little age-related change in the plasma concentrations of GH, T3 and T4 in sex-linked recessive dwarf chickens. Throughout growth and maturation the plasma concentrations of T3 in the sex-linked dwarf birds were less than 40% of those observed in the control strain. Plasma concentrations of T4 tended to be raised relative to the control in the sex-linked dwarf at each age examined. The plasma concentration of GH was raised only in older (12, 15 and 18 weeks old) sex-linked dwarfs. Liver T4-5′monodeiodinase activity was slightly depressed in autosomal dwarf chickens and very low in the sex-linked dwarf fowl. Neither autosomal nor sex-linked dwarfism appears to be due to hypopituitarism. It is probable that the depressed liver 5′monodeiodinase activity and the concomitant low plasma concentrations of T3 are a causative factor in the reduced growth and stature of the sex-linked dwarf chicken.

Circadian oscillations of body temperature in the marmoset, Callithrix jacchus

1978 ◽  
Vol 12 (2) ◽  
pp. 107-108 ◽  
Author(s):  
Colin M. Hetherington
Keyword(s):  
Circadian Rhythm ◽  
Body Temperature ◽  
Rectal Temperature ◽  
Callithrix Jacchus ◽  
Dark Phase ◽  
Light Phase

The rectal temperature of 8 marmosets was taken regularly throughout a 76 hour period. A pronounced circadian rhythm was detected: body temperature reached a maximum during the light phase and a minimum during the dark phase.

scholarly journals Melatonin MT1 and MT2 Receptors Exhibit Distinct Effects in the Modulation of Body Temperature across the Light/Dark Cycle

2019 ◽  
Vol 20 (10) ◽  
pp. 2452 ◽  
Author(s):  
Martha López-Canul ◽  
Seung Hyun Min ◽  
Luca Posa ◽  
Danilo De Gregorio ◽  
Annalida Bedini ◽  
...  
Keyword(s):  
Body Temperature ◽  
Receptor Antagonist ◽  
Partial Agonist ◽  
Receptor Subtypes ◽  
Dark Phase ◽  
Light Phase ◽  
Dark Cycle ◽  
Simultaneous Activation ◽  
Type 3 ◽  
G Protein Coupled

Melatonin (MLT) is a neurohormone that regulates many physiological functions including sleep, pain, thermoregulation, and circadian rhythms. MLT acts mainly through two G-protein-coupled receptors named MT1 and MT2, but also through an MLT type-3 receptor (MT3). However, the role of MLT receptor subtypes in thermoregulation is still unknown. We have thus investigated the effects of selective and non-selective MLT receptor agonists/antagonists on body temperature (Tb) in rats across the 12/12-h light–dark cycle. Rectal temperature was measured every 15 min from 4:00 a.m. to 9:30 a.m. and from 4:00 p.m. to 9:30 p.m., following subcutaneous injection of each compound at either 5:00 a.m. or 5:00 p.m. MLT (40 mg/kg) had no effect when injected at 5 a.m., whereas it decreased Tb during the light phase only when injected at 5:00 p.m. This effect was blocked by the selective MT2 receptor antagonist 4P-PDOT and the non-selective MT1/MT2 receptor antagonist, luzindole, but not by the α1/MT3 receptors antagonist prazosin. However, unlike MLT, neither the selective MT1 receptor partial agonist UCM871 (14 mg/kg) nor the selective MT2 partial agonist UCM924 (40 mg/kg) altered Tb during the light phase. In contrast, UCM871 injected at 5:00 p.m. increased Tb at the beginning of the dark phase, whereas UCM924 injected at 5:00 a.m. decreased Tb at the end of the dark phase. These effects were blocked by luzindole and 4P-PDOT, respectively. The MT3 receptor agonist GR135531 (10 mg/kg) did not affect Tb. These data suggest that the simultaneous activation of both MT1 and MT2 receptors is necessary to regulate Tb during the light phase, whereas in a complex but yet unknown manner, they regulate Tb differently during the dark phase. Overall, MT1 and MT2 receptors display complementary but also distinct roles in modulating circadian fluctuations of Tb.

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