Effects of Duodenal 5-Hydroxytryptophan Perfusion on Melatonin Synthesis in GI Tract of Sheep

Pan, Jun; Li, Fengming; Wang, Caidie; Li, Xiaobin; Zhang, Shiqi; Zhang, Wenjie; Zhao, Guodong; Ma, Castello; Liu, Guoshi; Yang, Kailun

doi:10.3390/molecules26175275

Cited by 6 publications

(6 citation statements)

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“… 53 Numerous studies have revealed that the highest intestinal melatonin levels are in the duodenum and rectum (mainly in the epithelium). 50 , 54 A similar phenomenon was found in fish, where melatonin was detected from the esophagus to the hindgut and melatonin synthase genes aanat1, aanat2 and hiomt mRNA were rhythmically expressed after removal of the pineal gland in rainbow trout (Oncorhynchus mykiss). 55 Our results showed that the expression of melatonin synthase Aanat was highest in the duodenum both during the day and at night, which was consistent with the above findings.…”

Section: Discussionsupporting

confidence: 54%

“… 49 Available studies have found that melatonin is also synthesized and secreted in large quantities in the gut, mainly by enterochromaffin cells and melatonin is present in different concentrations in different parts of the gut. 50 A study reported that different melatonin levels were detected in the cattle and pigs’ anterior and posterior segments of the gastrointestinal tract. 51 Melatonin secretion in different parts of the rat cerebellum, stomach, duodenum and pancreas followed a rhythmic pattern.…”

Section: Discussionmentioning

confidence: 99%

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Alterations of Gut-Derived Melatonin in Neurobehavioral Impairments Caused by Zinc Oxide Nanoparticles

Yang¹,

Lu²,

Xia³

et al. 2023

IJN

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Purpose The widespread use of zinc oxide nanoparticles (ZnONPs) has raised concerns about its potential toxicity. Melatonin is a neurohormone with tremendous anti-toxic effects. The enterochromaffin cells are an essential source of melatonin in vivo. However, studies on the effects of ZnONPs on endogenous melatonin are minimal. In the present study, we aimed to investigate the effects of ZnONPs exposure on gut-derived melatonin. Methods In the present study, 64 adult male mice were randomly and equally divided into four groups, and each group was exposed to ZnONPs (0, 6.5, 13, 26 mg/kg/day) for 30 days. Subsequently, the neurobehavioral changes were observed. The effects of ZnONPs on the expression of melatonin-related genes arylalkylamine N-acetyltransferase ( Aanat ), melatonin receptor1A ( Mt1 / Mtnr1a ), melatonin receptor1B ( Mt2 / Mtnr1b ), and neuropeptide Y ( Npy ) on melatonin synthesis and secretion in duodenum, jejunum, ileum and colon during day and night were also assessed. Results The results revealed that oral exposure to ZnONPs induced impairments of locomotor activity and anxiety-like behavior in adult mice during the day. The transcriptional analysis of brain tissues revealed that exposure to ZnONPs caused profound effects on genes and transcriptional signaling pathways associated with melatonin synthesis and metabolic processes during the day and night. We also observed that, in the duodenum, jejunum, ileum and colon sites, ZnONPs resulted in a significant reduction in the expression of the gut-derived melatonin rate-limiting enzyme Aanat , the membrane receptors Mt1 and Mt2 and Npy during the day and night. Conclusion Taken together, this is the first study shows that oral exposure to ZnONPs interferes with melatonin synthesis and secretion in different intestinal segments of adult mice. These findings will provide novelty insights into the neurotoxic mechanisms of ZnONPs and suggest an alternative strategy for the prevention of ZnONP neurotoxicity.

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Alterations of Gut-Derived Melatonin in Neurobehavioral Impairments Caused by Zinc Oxide Nanoparticles

Yang¹,

Lu²,

Xia³

et al. 2023

IJN

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“…China) was injected into the neck muscle of the lambs. After successful anesthesia, according to Pan et al [20], jugular vein, hepatic vein and portal vein blood were taken at 4 h after the morning feeding. The collected blood samples were centrifuged at 1500 g and 4˚C for 10 min to obtaine plasma.…”

Section: Sample Collection and Processingmentioning

confidence: 99%

Effects of dietary guanidinoacetic acid on growth performance, guanidinoacetic acid absorption and creatine metabolism of lambs

Zhang

Zang²,

Pan³

et al. 2022

PLoS ONE

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Guanidinoacetic acid (GAA) is the only precursor for the creatine synthesis of vertebrates. Creatine (Cr) and phosphocreatine (PCr) are able to provide energy for the rapid growth and development of the muscle tissue. This study evaluated the effects of dietary different levels GAA on growth performance, GAA absorption and creatine metabolism of lambs. Twenty-four 3-month-old healthy Kazakh male lambs (body weight = 27.35± 0.58 kg) were randomly divided into four groups with 6 lambs in each group. The lambs were fed with the basal diets supplemented with 0 (0 mg/kg group), 500 (500 mg/kg group), 1000 (1000 mg/kg group) and 1500 mg (1500 mg/kg group) GAA per kg diet (DM basis), respectively. The results showed that, as the GAA content of the diet increased, there was a quadratic change in DMI, with the lowest in the 500 mg/kg group and the highest in the 0 mg/kg group. The CK enzyme activity and ATP content in quadriceps muscle increased linearly with increasing levels of diary GAA in the diet. PCr levels and ADP levels in the longest dorsal muscle increased linearly with increasing levels of GAA in the diet. The relative expression of SLC6A6 and SLC6A8 mRNA in the jejunum and ileum mucosa showed a quadratic change as the dietary GAA level increased, with the lowest relative expression in both the 1500 mg/kg group. With the increase of dietary GAA level, both Cr concentration in hepatic vein plasma and the portal plasma GAA concentration shows a quadratic change, with the highest concentration in the 500 mg/kg group and the lowest concentration in the 0 mg/kg group. Therefore, dietary supplementation with 500~1000 mg/kg DM GAA is recommended for lambs.

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“…There have been 2 reports of the effects of melatonin precursor administration on plasma melatonin in sheep. 84,92 In the first study, sheep were injected intra peritoneally with tryptophan (500 mg/kg) and plasma melatonin was assayed by RIA following solvent extraction. 20 There was no consistent change in melatonin when tryptophan was administered either in the day or night.…”

Section: Stimulation Of Melatonin Production By Either 5-hydroxy Tryp...mentioning

confidence: 99%

“…Melatonin has been reported in gut tissue of other species (Table 5). In sheep, Pan et al 84 homogenised gut tissue and assayed the supernatant by direct ELISA (Beijing Sinouk Institute of Biological Technology). No details of any validation studies of this assay were provided.…”

Section: Git Melatonin Content In Ratsmentioning

confidence: 99%

The mammalian gastro‐intestinal tract is a NOT a major extra‐pineal source of melatonin

Kennaway

2023

Journal of Pineal Research

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In 1992, a paper reported that the melatonin content of the rat duodenum was 24 000 ± 2000 pg/g tissue (range: 4000–100 000 pg/g) while the pineal melatonin content was 580 000 ± 36 000 pg/g. The data has been used for the last 30 years to infer that the gut produces 400 hundred times more melatonin than the pineal gland and that it is the source of plasma melatonin during the daytime. No‐one has ever challenged the statement. In this review, evidence is summarised from the literature that pinealectomy eliminates melatonin from the circulation and that studies to the contrary have relied upon poorly validated immunoassays that overstate the levels. Similarly studies that have reported increases in plasma melatonin following tryptophan administration failed to account for cross reactivity of tryptophan and its metabolites in immunoassays. The most extraordinary observation from the literature is that in those studies that have measured melatonin in the gut since 1992, the tissue content is vastly lower than the original report, even when the methodology used could be overestimating the melatonin content due to cross reactivity. Using the more contemporary results we can calculate that rather than a 400:1 ratio of duodenum: pineal melatonin, a ratio of 0.05–0.19: 1 is likely. The gut is not a major extra‐pineal source of melatonin; indeed it may well not produce any.

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Effects of Duodenal 5-Hydroxytryptophan Perfusion on Melatonin Synthesis in GI Tract of Sheep

Cited by 6 publications

References 55 publications

Alterations of Gut-Derived Melatonin in Neurobehavioral Impairments Caused by Zinc Oxide Nanoparticles

Alterations of Gut-Derived Melatonin in Neurobehavioral Impairments Caused by Zinc Oxide Nanoparticles

Effects of dietary guanidinoacetic acid on growth performance, guanidinoacetic acid absorption and creatine metabolism of lambs

The mammalian gastro‐intestinal tract is a NOT a major extra‐pineal source of melatonin

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