The physiological role of L Arginine
By taking L-arginine powder and citrulline, metabolic disorder syndrome and unnecessary fat deposition can be reduced in obese people and animals. As the precursor of the biologically active factor nitric oxide (NO), effects of arginine on controlling obesity and its mechanism have recently made a breakthrough.Studies at the molecular level have shown that the mechanism of action of arginine mainly includes the following aspects:
- NO produced by arginine can stimulate the phosphorylation of Therefore, by inhibiting the activity of acetyl COA carboxylase and activating the activity of malonyl COA decarboxylase, the content of malonyl COA can be reduced, and the genes related to fat and glycogen synthesis can be reduced.
- NO can increase the phosphorylation of hormone-sensitive lipase and translocate it to neutral fat granules, thereby activating fat degradation.
- NO can activate PPARy co-activator α1, thereby increasing mitochondrial oxidative phosphorylation.
- NO increases blood flow in insulin-sensitive tissues, thereby increasing substrate metabolism.
Regulate the growth of tumor cells
The process of tumor metastasis is the result of the joint action of many factors. Tumor cells break away from the primary tumor tissue and migrate along with lymphatic vessels, blood vessels or directly to other tissues of the body to form new tumor metastases. During this process, intercellular adhesion molecules and vascular cell adhesion molecules are closely related to the recurrence and metastasis of malignant tumors. Meanwhile, MMPs are involved in many physiological and pathological processes. Tissue inhibitors of metalloproteinases (TIMPs) can play an important role in tumor invasion, metastasis and tissue fibrosis by inhibiting MMPs.
As a precursor of NO synthesis, arginine can inhibit matrix metalloproteinases, inhibit cell adhesion molecules and increase the expression of tissue inhibitors of matrix metalloproteinases to prevent cell adhesion. In addition, a certain concentration of arginine can induce apoptosis and inhibit tumor cell proliferation by increasing the synthesis of NO to exert cytotoxicity.
Role in the cardiovascular system
Arginine and molecular oxygen generate NO under the catalysis of NOS and its cofactors. NO plays an important role in maintaining the constant of vascular tension and regulating the stability of blood pressure. Under physiological conditions, when the blood vessels are impacted by blood flow and the perfusion pressure suddenly rises, NO can maintain the relative stability of the blood flow of the organs, so that the blood vessels have a self-regulating effect. At the same time, it can reduce the mean arterial blood pressure of the whole body, control the resting tension of various vascular beds in the whole body, increase local blood flow, and is the main regulator of blood pressure. The possible mechanism for NO to play a role in the cardiovascular system is to increase the activity of guanylate cyclase (GC) in cells, promote the cyclization of guanosine monophosphate to produce cyclic guanosine monophosphate (cGMP), and increase the level of cGMP in cells. Then, activation of cGMP-dependent protein kinase strengthens the phosphorylation of cardiac troponin C, the affinity of troponin C to Ca2+ decreases, and the activity of K+ channels on the muscle cell membrane also decreases, resulting in vasodilation.
Role in the immune system
Due to its special position in the urea cycle, L arginine can reduce blood ammonia concentration and reduce body cell damage. Most of the effects of arginine on animal diseases are through the NO pathway, and macrophages generate NO through arginine. When macrophages are activated, the NO released by them can exert the effect of killing target cells and protect the body by inhibiting the tricarboxylic acid cycle, electron transfer and cellular DNA synthesis in the mitochondria of target cells. Arginine metabolism has a role in balancing the immune response and is especially important for macrophages and T cells.
Role in the nervous system
NO diffuses and acts on adjacent peripheral neurons, such as pre-herniated nerve endings and astrocytes, and then activates GC to increase the level of CGMP to produce physiological effects. The arginine/NO pathway also exists in the peripheral nervous system. NO is considered as a non-cholinergic, non-adrenergic neurotransmitter or mediator, involved in pain transmission and sensory transmission process. In addition, NO plays an important mediating role in the relaxation of gastrointestinal smooth muscle mediated by gastrointestinal nerves. At the same time, as a neuron transmitter, NO plays an important role in the genitourinary system and becomes a regulating substance for physiological functions such as urinary continence.
Role in endocrine
Arginine can stimulate the pancreas, adrenal gland, thalamus and other parts to produce hormones. Arginine is critical for the regulation of prolactin and growth hormone. Animals regulate protein and amino acid metabolism through the growth hormone and IGF-1. Arginine stimulates growth hormone release either by its direct action or by its metabolites. Arginine is metabolized in the brain to ornithine, which in turn produces glutamate, both of which stimulate the release of growth hormone. In addition, NOS exists in the hypothalamus and pituitary area, and NO can promote the release of growth hormone. Arginine stimulates insulin release in humans and other mammals including cattle, sheep and pigs.