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Cholinesterase enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are traditionally associated with the termination of acetylcholine mediated neural signaling. The fact that these ubiquitous enzymes are also found in tissues not involved in neurotransmission has led to search for alternative functions for these enzymes. Cholinesterases are reported to be involved in many lipid related disease states. Taking into view that lipases and cholinesterases belong to the same enzyme class and by comparing the catalytic sites, we propose a new outlook on the link between BChE and lipid metabolism. The lipogenic substrates of BChE that have recently emerged in contrast to traditional cholinesterase substrates are explained through the hydrolytic capacity of BChE for ghrelin, 4‐methyumbelliferyl (4‐mu) palmitate, and arachidonoylcholine and through endogenous lipid mediators such as cannabinoids like anandamide and essential fatty acids. The abundance of BChE in brain, intestine, liver, and plasma, tissues with active lipid metabolism, supports the idea that BChE may be involved in lipid hydrolysis. BChE is also regulated by various lipids such as linoleic acid, alpha‐linolenic acid or dioctanoylglycerol, whereas AChE is inhibited. The finding that BChE is able to hydrolyze 4‐mu palmitate at a pH where lipases are less efficient points to its role as a backup in lipolysis. In diseases such as Alzheimer, in which elevated BChE and impaired lipid levels are observed, the lipolytic activity of BChE might be involved. It is possible to suggest that fatty acids such as 4‐mu palmitate, ghrelin, arachidonoylcholine, essential fatty acids, and other related lipid mediators regulate cholinesterases, which could lead to some sort of compensatory mechanism at high lipid concentrations. [ABSTRACT FROM AUTHOR]

Background: The study aimed to investigate whether timolol-treatment has a beneficial effect on pentose phosphate pathway enzyme activities such as glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGDH) enzyme activities and cAMP level in streptozotocin-induced diabetic rats in pancreatic tissues Methods: Diabetes was induced by streptozotocin (STZ) in 3-month old male Wistar rats. The diabetic rats were treated with timolol (5 mg/kg body weight, for 12 weeks) while the control group received saline. Enzyme activities were determined in pancreas tissue. To support our results, we performed in silico calculations, using Protein Data Bank structures. Results: Timolol treatment of STZ-induced diabetic rats had no noteworthy effect on high blood-glucose levels. However, this treatment induced activities of G6PD and 6PGDH in diabetic rats. Timolol treatment significantly increased cAMP level in diabetic pancreatic tissue. We found that timolol cannot bind strongly to either G6PD or 6PGD, but there is a relatively higher binding affinity to adenylyl cyclase, responsible for cAMP production, serving as a regulatory signal via specific cAMP-binding proteins. Conclusions: Our data point out that timolol treatment has beneficial effects on the antioxidant defence mechanism enzymes in the pancreas of STZ-induced diabetic rats.

PurposeMethodsResultsConclusionsTo evaluate matrix metalloprotease-1 (MMP-1), matrix metalloprotease-3 (MMP-3), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) levels in the eyelid skin and fibroadipose tissue in patients with inactive moderate-to-severe Graves’ orbitopathy (GO).This prospective study included 23 patients with inactive moderate-to-severe GO who underwent upper blepharoplasty and medial fat excision, and 22 age- and sex-matched healthy subjects. MMP-1, MMP-3, TNF-α, and IL-6 levels in the skin and fibroadipose tissue obtained during surgery were measured using the ELISA method.The mean MMP-1 level in the eyelid skin (p = .003) and the mean MMP-3 level in the fibroadipose tissue (p = .04) were significantly lower in the GO group compared to the healthy control group. There were no differences in other mediators in both tissues between the two groups (p > .05).The lower levels of proteolytic enzymes such as MMP-1 and MMP-3 in the eyelid skin and orbital fibroadipose tissue of patients with chronic inactive GO may play a role in the increase of collagen and glycosaminoglycans in orbital soft tissues. [ABSTRACT FROM AUTHOR]