Diurnal and seasonal changes in endogenous melatonin levels in the blood plasma in dogs

Zań, R; Roliński, Z; Kowalski, C.; Bojarska‐Junak, Agnieszka; Madany, J.

doi:10.2478/pjvs-2013-0110

Cited by 9 publications

(5 citation statements)

References 5 publications

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“…Physiological levels of melatonin in healthy dogs is dependent of diurnal cycle and season, rising during the night and in autumn-winter seasons. These plasma levels fluctuate between 2 and 13 pg/ml, depending on the factors already mentioned [10, 11]. On tumour cells, this liposoluble hormone has pleiotropic effects including antioxidant, anti-angiogenic, pro-apoptotic and antiproliferative effects through receptor-dependent and receptor-independent mechanisms [12, 13], nevertheless, its actions on CSC has been poorly studied [14].…”

Section: Introductionmentioning

confidence: 99%

Melatonin decreases in vitro viability and migration of spheres derived from CF41.Mg canine mammary carcinoma cells

et al. 2019

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BackgroundMammary cancer is a common disease affecting female dogs, where approximately 50% of the cases are malignant. There is a subpopulation of cancer cells with stem cell-like features within the tumour microenvironment, which can form in vitro spheres, cell structures that grow in anchor-free conditions. This cell population shows resistance to conventional antitumor treatments explaining in part the recurrence of some type of cancers. It has been previously reported that spheres derived from CF41.Mg canine mammary carcinoma cells exhibit several stemness features. Melatonin has shown antitumor effects on cancer mammary cells; nevertheless, its effects have been poorly evaluated on canine mammary cancer stem-like cells. In this regard, it has described that melatonin decreases the expression of OCT-4 in CMT-U2229 mammary cancer cells, a transcription factor that participates in the modulation of self-renewal and drug resistance in cancer stem-like cells. The aim of this study was to compare the effects of melatonin on viability and migration of canine mammary carcinoma CF41.Mg-spheres, and CF41.Mg-parental cells. CF41.Mg cells were grown in DMEM high-glucose medium containing 10% bovine foetal serum. CF41.Mg-spheres were cultured in ultra-low attachment plates with serum-free DMEM/F12 containing several growth factors. Cell viability (MTS reduction) and migration (transwell) assays were conducted in presence of melatonin (0.01, 0.1 or 1 mM).ResultsMelatonin decreased cell viability at 1 mM (P < 0.05), with a significant reduction in spheres compared to parental cells at 24 and 48 h (P < 0.05). Cell migration was inhibited in response to non-cytotoxic concentration of melatonin (0.1 mM) (P < 0.05) in spheres and monolayer of cells, no significant differences were detected between both cell subtypes.ConclusionsThese results indicate that melatonin reduces viability and migration of CF41.Mg cells, where spheres exhibit greater sensitivity to the hormone. Thus, melatonin represents a valuable potential agent against mammary cancer cells, especially cancer stem-like cells.

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Section: Introductionmentioning

confidence: 99%

Melatonin decreases in vitro viability and migration of spheres derived from CF41.Mg canine mammary carcinoma cells

et al. 2019

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“…In contrast, some studies report much lower serum concentrations of melatonin in the dog. Zan et al (2013), using an ELISA kit, reported mean values below 14 pg/mL, varying with time of day and season in a pilot study with 6 dogs [ 28 ]. Dunlap et al (2007), using a radioimmunoassay, reported similar results with mean values <20 pg/mL, also with diurnal and seasonal changes [ 20 ].…”

Section: Discussionmentioning

confidence: 99%

“…It is possible that the large variation in serum melatonin concentrations might have obscured a treatment effect. It is unlikely that time of sampling affected the results, as all samples were collected during daytime (between 8:00 and 17:00) [ 20 , 28 ]. Time after treatment might have affected the results.…”

Section: Discussionmentioning

confidence: 99%

A Pilot Study to Evaluate the Potential of Melatonin Implants to Control Cyclicity in the Bitch

Axnér

2023

Animals

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In short-day breeders such as the sheep, melatonin stimulates oestrus activity; in contrast, a high serum concentration of melatonin inhibits oestrus in long-day breeders such as the cat. Therefore, implants with melatonin have been used to suppress or induce oestrus depending on the species. The aim of this pilot study was to evaluate if melatonin could be an alternative to control the reproductive cycle in the bitch. Nine beagle bitches were observed for three oestrus cycles. Five beagle bitches were treated with 18 mg melatonin implants on average 27 days before the next expected oestrus based on the previous interoestrus interval. Four bitches served as untreated controls. Blood samples for evaluation of serum melatonin were collected at the time of assignment to treatment or control group and 1–4 weeks thereafter. Clinical signs and vaginal smears were used to follow the cycle. Melatonin varied significantly with bitch (p < 0.05) but not with treatment. Treatment did not affect the interoestrus interval (p > 0.05). In conclusion, treatment with 18 mg melatonin implants approximately one month before expected oestrus is not likely to be a useful method to control cyclicity in the bitch. It is still not known if melatonin is involved in regulation of the oestrus cycle in the domestic dog.

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“…Two-fold fluctuations have been described during light-cycle changes in the different seasons ( 37 ). The synthesis of melatonin is always highest at night but decreases at dawn, remaining at low levels throughout the day; the lowest levels of this hormone were recorded on summer mornings, whereas the highest concentrations were reached on winter nights ( 38 ). The effects of latitude, exercise, and season on melatonin concentration have been described in dogs ( 39 ).…”

Section: Discussionmentioning

confidence: 99%

Photoperiod and Melatonin Supplementation: Variable Effects on the Quality of Chilled Dog Semen

Mitjana

Ausejo

Mendoza³

et al. 2022

Front. Vet. Sci.

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The addition of melatonin in seminal extenders due to its antioxidant properties and its beneficial role in sperm preservation has been previously described, especially in seasonal species. The aim of this study was to study a potential seasonal effect based on photoperiod duration when adding a physiological concentration of melatonin in the canine ejaculate. A total of 24 ejaculates were obtained from 10 healthy dogs during the increasing photoperiod (from December 21 to June 21), whereas 12 ejaculates were collected from five healthy individuals during the decreasing photoperiod (from June 22 to December 20). Each ejaculate was separated into two aliquots, and one of them remained as a control, whereas melatonin (100 pM) was added to the other one (C and M treatment groups, respectively). Diluted semen was refrigerated at 5°C. On days 0, 1, 2, 3, and 6, sperm motility analyses were performed using a CASA system and hypoosmotic swelling test (HOST), osmotic resistance test (ORT), and flow cytometry analysis. No effect of melatonin on motility was detected in either photoperiod. Negative effects of melatonin were found for acrosomal defects, apoptosis, and viability in the decreasing photoperiod. The addition of melatonin to sperm in the decreasing photoperiod could create such a high level that it would cause the described negative effects. We found a beneficial effect of melatonin in the increasing photoperiod on acrosomal defects and apoptosis during 0–6 days. Melatonin treatment also increased viability in the short term (days 1 and 2) for both photoperiods. Also, melatonin can provide certain beneficial effects on mitochondrial activity in the medium term (days 2 and 3) in the decreasing photoperiod.

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Diurnal and seasonal changes in endogenous melatonin levels in the blood plasma in dogs

Cited by 9 publications

References 5 publications

Melatonin decreases in vitro viability and migration of spheres derived from CF41.Mg canine mammary carcinoma cells

Melatonin decreases in vitro viability and migration of spheres derived from CF41.Mg canine mammary carcinoma cells

A Pilot Study to Evaluate the Potential of Melatonin Implants to Control Cyclicity in the Bitch

Photoperiod and Melatonin Supplementation: Variable Effects on the Quality of Chilled Dog Semen

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