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The Production of Biologically Active Peptides in Brain Tissues
Published in Gerard O’Cuinn, Metabolism of Brain Peptides, 2020
These brain-gut peptides are structurally (Table 2) and functionally related. Somewhat analogous to the neurohypophyseal hormones the genes for gastrin and cholecystokinin appear to have arisen by duplication of an ancestral gene. The genes for gastrin and cholecystokinin can be aligned on two criteria: (a) at the putative initiator methionines in the respective second exon and (b) at the conserved pentapeptide (Table 2) of the prehormones, in their third exons.38
Prolactin
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
Prolactin is synthesized in the endoplasmic reticulum as a prehormone.1 A 30-amino acid leader peptide sequence is cleaved from the prolactin prehormone when the molecule enters the lumen of the endoplasmic reticulum. Prolactin is then transported to the golgi where it is packaged in secretory vesicles or granules. Within the prolactin granules there is further concentration of the hormone. Chemical bonding between the prolactin molecules within a granule, perhaps by sulfation, facilitates the concentration of prolactin. “Older” prolactin granules can coalesce into larger granules.48 It is thought that these large granules are destined for degradation by lysosomal activity in a process called crinophagy.
Acupuncture and Traditional Chinese Medicine
Published in Mark V. Boswell, B. Eliot Cole, Weiner's Pain Management, 2005
Some patients do not react favorably to acupuncture. These nonresponders may be deficient, genetically or otherwise, in opiate receptors (Peets & Pomeranz, 1978). Nonresponder results may be improved by the addition of dl-phenylalanine, an essential amino acid, at 750 to 1,000 mg daily to potentiate endorphin release (Hendler, 2001). Other factors influencing acupuncture efficacy are under investigation. In animal models, Lee et al. (2003) demonstrated that the analgesic effect of acupuncture is closely related to the amount of genetic expression of cholecystokinin-A receptors. Cholecystokinin is a peptide prehormone secreted from mucosal epithelial cells in the small intestine and produced by neurons in the enteric nervous system. It is widely distributed in the brain and may be the most abundant neuropeptide in the central nervous system.
Diagnostic and prognostic value of new bioscore in critically ill septic patients
Published in Archives of Physiology and Biochemistry, 2022
Pinar Sen, Tuna Demirdal, Salih Atakan Nemli, Atilla Sencan
PCT is secreted as prehormone of calcitonin against hypercalcemia from C cells of the thyroid gland (Simon et al. 2004). This hormone is released from thyroid C cells, lung, liver, intestines and pancreatic neuroendocrine cells during inflammation (Cho and Choi 2014). Therefore, this molecule has negligible serum concentration in healthy individuals and it has been found that PCT was elevated especially in bacterial inflammation, sepsis and organ failure (Liu et al. 2015). Hence, PCT is more specific than other biomarkers in differentiating bacterial and non-bacterial inflammation (Li et al. 2016). Nevertheless, some clinical conditions such as cardiogenic shock, multiple trauma, surgery, burn, drug sensitivity reactions and hypothermia can lead to increase in PCT levels (Uzzan et al. 2006, Hausfater et al. 2007). Additionally, various studies have shown that PCT had a low sensitivity for detecting some infection such as abdominal sepsis (Jung et al. 2013). In our study, PCT levels did not differ significantly between surgically and medically treated patients. Also, we indicated that PCT was better for sepsis recognition than other markers examined, whereas the AUC of bioscore was higher for septic patients in critical care. Therefore, we believe that the combination of PCT with other biomarkers such as bioscore may be more useful in the diagnosis of sepsis.
The pressing need for standardization in epidemiologic studies of PCOS across the globe
Published in Gynecological Endocrinology, 2019
Michael Ntumy, Ernest Maya, Daria Lizneva, Richard Adanu, Ricardo Azziz
And even more difficult may be defining HA biochemically. Should we assess total Testosterone (T), free T, DHEA, androstenedione (A4), dihydrotestosterone (DHT)? Others? One, some or all? Evaluating a cohort of PCOS patients diagnosed by the NIH 1990 criterion, total T alone (using a high-quality assay) detected some 33% of patients, the addition of free T measures increased the detection rate to 60%, and the addition of DHEA and A4 increased the detection rate by approximately 7–10% each. And speaking of androgen measures, the quality of assays vary widely. Total T is the mainstay of androgen measures in women, alone and in the estimation of free T and the standard for total T assay is either a high quality radio-immunoassay following sample extraction and column chromatography or, better still, mass spectrometry. Yet the quality of total T varies widely in studies of PCOS and many investigators use total T (generally alone) measured by direct platform immunoassays. In fact, Lizneva and colleagues observed in their meta-analysis that the weakest areas of reporting were related to insensitive androgen measures [2]. So which assays and hormones or prehormones should be assessed in detecting PCOS? And as androgens change with age should age-related cutoff values be used?
Modulation of VDR and Cell Cycle-Related Proteins by Vitamin D in Normal Pancreatic Cells and Poorly Differentiated Metastatic Pancreatic Cancer Cells
Published in Nutrition and Cancer, 2019
Lei Li, Feifei Shang, Yadong Zhu, Yanfu Sun, Radha Sharan Sudi
The role of VD in cancer prevention is made confusing by the differences between the results of in vitro studies and human epidemiological studies. VD works as a hormone and exerts its biological effects by binding to its nuclear receptor VDR. There are several VD metabolites in the body. The active form of VD is 1,25(OH)2D3, or calcitriol, that binds to its VDR with high affinity (Kd =10−11 M) and selectivity (22). The most abundant VD metabolite is the prehormone form 25-hydroxyvitamin D, or calcifediol. Calcifediol is activated into calcitriol in the kidney by one hydroxylation reaction (23). Calcitriol is responsible for the many cellular effects observed in in vitro studies, but, in general, calcifediol levels have been measured in human cohort studies to determine the association between the level of VD and cancer risk. Early studies showed that calcifediol concentration does not reflect the level of calcitriol in the body (24). Chesney et al. found that the serum concentration of calcitriol remains constant despite seasonal variation in calcifediol (24). The serum concentration of calcifediol is more likely to change with exposure to UBV radiation and dietary supplements of VD metabolites, but its activation into calcitriol in the kidneys is tightly regulated to maintain the necessary homeostasis. The only argument that could support the use of the level of calcifediol in human studies on the association of VD with cancer is that the binding activity of calcifediol to VDR is low and has a low affinity. However, the binding activity of calcifediol is easily counteracted by the regulated changes in the level of calcitriol.