| dc.description.abstract | Oxytocin is a central nervous system neuropeptide hormone, which is composed of nine amino acids. The synthesis of oxytocin begins in the hypothalamus, where the paraventricular nucleus and supra-optic neurons express high levels of oxytocin, which is released from the posterior pituitary gland. Whereas "Fasting" may be defined as voluntary abstinence from food and drink for specified, recurring periods of time, with the fasting periods typically ranging from 12 hours to three weeks in humans. Hippocrates recommended fasting during sickness and was probably one of the first advocates of fasting for medical purposes. There exists limited information showing a direct relationship between oxytocin synthesis and fasting.
In order to determine the change that occur in oxytocin levels during fasting, Lnpep a gene that is involved in its metabolism in the liver was considered. Its levels of expression were to be monitored under different conditions. Data was obtained from the NCBI Gene Expression Omnibus (GEO) database; two datasets were selected for this study, (accession numbers GSE137385 and GSE130127). From the different GSEs, extrapolation of the following dataset information was done: run, assay type, library layout, organism, platform, strain, tissue and treatment. From GSE130127, selected were 9 runs beginning SRR89371 which is represented as X followed by the last 3 digits from each run as shown from (table 1) through the analysis of the results. In the first group AL had 3 samples (X153, X154,X155) , in the second group IF16h3wks 3 samples were selected (X158,X159,X160), in the third group IF24h3wks 3 samples were selected (X163,X164,X165) and only 3 samples were selected from GSE137385, the 3 runs beginning with SRR10112 which also was represented as X followed by the last 3 digits from each run as shown in, thus the fourth group 21fast 3 samples were selected (X565,X566,X567). A total of 12 samples were selected for comparing the different time points i.e (fasting for 21 hour a one day fast 21fast, fasting for 16 hours for 3 weeks IF16h3wks, fasting for 24 hours for 3 weeks) IF24h3wks and the fed condition 0 hours of fasting AL.
The gene signatures exhibited by mice under ad libitum feeding (AL), mice that fasted for 21 hours(21fast), mice under intermitted fasting for 16 hours in 3 weeks (IF16h3wks) and mice under intermitted fasting for 24 hours in 3 weeks (IF24h3wks) indicate differentiation in gene expression according to the PCA, the abnormality seen in the 21fast may be due to the presence of the different mouse strains in the this group this resulted in the genes with expression levels significantly higher in C57BL/6J mice than in BALB/cJ mice and distinct clustering of experimental groups using heat map analysis. Even though common genes that are differentially expressed by in all fasting groups and AL are present, it can be further observed that a large number of differentially expressed genes are unique to either the 21fast or the IF24h3wks regimen. This showed that the longer the fasting time of the day the more genes are significantly expressed. Fasting resulted as expected in marked weight loss with reduction of abdominal circumference, which was more pronounced in the groups which was fasted longer. On the other side, Pilot data suggest that longer -term oxytocin administration may support weight loss in obese patients. These findings provided evidence that fasting longer could be similar to longer-term oxytocin administration. Since a particular level of oxytocin is attained when an individual fasts thus, as one fasts longer this dose of oxytocin is attained, thus bring about a similar effect observed in fasting and oxytocin administration.
These results provide evidence that there is a direct relationship between fasting oxytocin synthesis levels in mice. It was noted that there is threshold oxytocin level which was observed in all fasting groups and this could be the required oxytocin level need to bring about the beneficial effects observed during fasting. However, this calls for further studies to monitor oxytocin synthesis using brain tissue as to understand which exact genes involved in its synthesis are up regulated and to what extent during different fasting conditions. | en_US |
