Endogenous Metabolite

Cellular cholesterol concentration decreased by 20–31% after GT1-7 hypothalamus cells were depleted of cholesterol in vitro. Reduced phosphorylation/activation of IRS-1 and AKT was observed in all cholesterol-depleted neuron-derived cells when stimulated with insulin, insulin-like growth factor 1, or neurotrophic factors (NGF and BDNF). Lowering cellular cholesterol also raises baseline autophagy and hinders glucose deprivation-induced autophagy activation [1].

Cholesterol is commonly used to establish models of hyperlipidemia and atherosclerosis. Its metabolic half-life ranges from hours to years, depending on the type of lipoproteins it associates with and the specific tissues involved.
Induction of Hyperlipidemia
Background
Hyperlipidemia refers to a group of conditions characterized by elevated blood lipid levels, including cholesterol, cholesterol esters, phospholipids, and triglycerides. Excessive cholesterol intake that exceeds the body's metabolic capacity can lead to increased plasma cholesterol levels, thereby inducing hyperlipidemia.
Modeling Protocol
- Animal: Male Wistar rats, 18 weeks old (duration: 8 weeks) - Treatment: 2% cholesterol administered via diet for 8 weeks
Notes
(1) Rats are housed in a temperature-controlled environment (22 ± 2°C) with a 12-hour light/dark cycle.
(2) Wistar rats are the preferred species for hyperlipidemia studies because a high-cholesterol diet induces only moderate elevations in serum cholesterol and triglycerides without causing significant atherosclerosis. This allows for the study of direct cardiac effects of hyperlipidemia independent of atherosclerotic changes.
Modeling Indicators
- Molecular changes: A significant increase (approximately 20%) in total cholesterol levels in blood samples.

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Induction of Atherosclerosis
Background
Excess blood cholesterol, particularly low-density lipoprotein cholesterol (LDL-C), can accumulate as plaque on blood vessel walls—a process known as atherosclerosis. Over time, these plaques can obstruct blood flow and lead to serious conditions such as myocardial ischemia or infarction.
Modeling Protocol
- Animal: Male rabbits (Oryctolagus cuniculus), 4–6 months old (duration: 16 weeks)
- Treatment: 0.3% cholesterol and 3% soybean oil administered via diet for 16 weeks
Notes
(1) Cholesterol-fed rabbits are widely used in experimental atherosclerosis research because cholesterol induces atherosclerotic changes specifically in the intima of rabbit arteries, closely resembling human atherosclerosis.
(2) Since fat is required for intestinal cholesterol absorption, oil must be added to the diet. Otherwise, rabbits may consume their own body fat, leading to weight loss or illness. Soybean oil, composed of unsaturated fatty acids, helps prevent excessively high plasma cholesterol levels. Other vegetable oils (e.g., peanut or corn oil) are also suitable due to their unsaturated fat content. Animal fats such as tallow or lard (saturated fats) are not recommended.
(3) Most experimental protocols recommend a diet containing 0.3–0.5% cholesterol. Diets with 1–2% cholesterol are poorly tolerated beyond one month due to the risk of severe liver dysfunction.
(4) Adult rabbits aged 4 months or older typically consume about 150 g of food daily. Feeding may be ad libitum or restricted (100–150 g/day/adult rabbit).
(5) Plasma lipids should be measured weekly, especially during the first 4 weeks, to confirm elevated cholesterol levels in each animal. Non-responsive rabbits that fail to show increased plasma cholesterol after the cholesterol-enriched diet may be excluded from the study.
(6) Once plasma cholesterol levels stabilize, plasma lipoproteins can be assessed at 8 and 16 weeks.
(7) Rabbit age should be considered, as younger animals are more prone to aortic atherosclerosis than older ones even when plasma cholesterol levels are similar. Rabbits aged 4–6 months are typically used for cholesterol feeding experiments.
(8) Male and female rabbits respond differently to a cholesterol-rich diet and atherosclerosis development. In our experience, females exhibit higher susceptibility to hypercholesterolemia and aortic lesions than males. Therefore, male rabbits are generally recommended for experiments to avoid potential confounding effects of female hormones.
Modeling Indicators
- Histological changes: Atherosclerotic lesions are observable in the aortic arch and thoracic aorta sections under hematoxylin and eosin (HE) staining.

Diabetes mellitus is associated with a variety of complications, including alterations in the central nervous system (CNS). We have recently shown that diabetes results in a reduction of cholesterol synthesis in the brain due to decreased insulin stimulation of SREBP2-mediated cholesterol synthesis in neuronal and glial cells. In the present study, we explored the effects of the decrease in cholesterol on neuronal cell function using GT1-7 hypothalamic cells subjected to cholesterol depletion in vitro using three independent methods: 1) exposure to methyl-β-cyclodextrin, 2) treatment with the HMG-CoA reductase inhibitor simvastatin, and 3) shRNA-mediated knockdown of SREBP2. All three methods produced 20-31% reductions in cellular cholesterol content, similar to the decrease in cholesterol synthesis observed in diabetes. All cholesterol-depleted neuron-derived cells, independent of the method of reduction, exhibited decreased phosphorylation/activation of IRS-1 and AKT following stimulation by insulin, insulin-like growth factor-1, or the neurotrophins (NGF and BDNF). ERK phosphorylation/activation was also decreased after methyl-β-cyclodextrin and statin treatment but increased in cells following SREBP2 knockdown. In addition, apoptosis in the presence of amyloid-β was increased. Reduction in cellular cholesterol also resulted in increased basal autophagy and impairment of induction of autophagy by glucose deprivation. Together, these data indicate that a reduction in neuron-derived cholesterol content, similar to that observed in diabetic brain, creates a state of insulin and growth factor resistance that could contribute to CNS-related complications of diabetes, including increased risk of neurodegenerative diseases, such as Alzheimer disease [3].

Cholesterol can be used for constructing aimal models of hyperlipidemia, atherosclerosis, and so on.

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\nInduction of hyperlipidemia
\nPathogenic principle: Hyperlipidemia is a group of diseases characterized by elevated circulating lipid concentrations, including cholesterol, cholesterol esters, phospholipids, and triglycerides. If the intake of cholesterol is excessive and exceeds the body's metabolic capacity, it may lead to an increase in plasma cholesterol levels and induce hyperlipidemia.
\nDetailed methods for constructing hyperlipidemia model
\nRats: Wistar • male • 18 week old (period: 8 weeks)
\nAdministration: 2% cholesterol; Diet-8 weeks
\nNote
\n(1) The rats were placed in a room with 22 ± 2 ° C room temperature and 12 h light dark cycle
\n(2) Wistar rats were always selected for the study of hyperlipidemia, because the serum cholesterol and triglyceride levels of this species were moderately increased due to high cholesterol diet, and no substantial atherosclerosis occurred; Therefore, it is possible to study the direct effect of hyperlipidemia on myocardium in this model, independent of atherosclerosis.
\nMarkers of successful construction of hyperlipidemia model: Total cholesterol levels in blood samples significantly increase (approximately 20%)

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\n\nInduction of atherosclerosis
\nPathogenic principle: High levels of cholesterol in the blood, especially low density lipoprotein cholesterol (LDL-C), may accumulate on the vascular wall to form plaque, a process known as atherosclerosis. Over time, these plaques may block blood flow, leading to serious health problems such as myocardial ischemia or myocardial infarction.
\nDetailed methods for constructing atherosclerosis model
\nRabbits: Oryctolagus cuniculus • male • 4-6 month old (period: 16 weeks)
\nAdministration: 0.3% cholesterol and 3% soybean oil; DIET • 16 weeks
\nNote
\n(1) High cholesterol rabbit is a model widely used in experimental research of atherosclerosis, because cholesterol can only cause atherosclerosis changes in the intima of rabbit arteries, which is very similar to human atherosclerosis.
\n(2) Due to the absorption of dietary cholesterol requiring fat, oil must be added to the diet. Otherwise, rabbits will use their internal fat to make them thin or sick. In addition, using soybean oil containing unsaturated fatty acids can prevent high plasma cholesterol levels. Other vegetable oils, such as peanut oil or corn oil, can also be used because they are unsaturated fatty acids. It is not recommended to consume animal fats (saturated fatty acids), such as butter and lard.
\n(3) Most experiments recommend using a cholesterol diet of 0.3-0.5%. Rabbits cannot tolerate a cholesterol diet of 1-2% for more than a month as they can develop severe liver dysfunction.
\n(4) Adult rabbits over 4 months old can consume approximately 150 grams per day. Free feeding or restricted feeding (100-150 grams/day/adult rabbit) is allowed.
\n(5) Blood lipids should be measured weekly, especially for the first 4 weeks, as you need to determine whether the plasma cholesterol levels of each animal are elevated. If the plasma cholesterol level of non responsive rabbits does not increase after feeding with cholesterol feed, they can be excluded from the experiment.
\n(6) Plasma lipoprotein can be measured at 8 and 16 weeks, during which plasma cholesterol levels remain stable.
\n(7) The age of rabbits should be considered, because even though their plasma cholesterol levels are similar, young rabbits are more likely to suffer from atherosclerosis than older rabbits. Rabbits aged 4-6 months are typically used for cholesterol feeding experiments.
\n(8) Male and female rabbits have different responses to cholesterol diet and atherosclerosis. Based on our experience, female rabbits suffer from higher levels of hypercholesterolemia and larger aortic lesions than male rabbits. In general, it is recommended to conduct experiments on male rabbits as estrogen may affect the results.
\nMarkers of successful construction of therosclerosis model: Histological changes: HE staining of aortic arch and sections of thoracic aorta showed atherosclerosis

Absorption, Distribution and Excretion
Cholesterol is present in all body tissues, especially in the brain, spinal cord, and animal fats or oils. It is a major component of gallstones.
Cholesterol is widely distributed in all animal tissues. It can originate from the absorption of dietary cholesterol in the intestines or from de novo synthesis within the body.
The absorption rate of dietary cholesterol depends on intake; after reaching a certain level, absorption decreases as dietary intake increases. Most people in Western societies consume 500 to 800 mg of cholesterol daily, with an absorption rate of 300 to 400 mg.
Cholesterol is absorbed from the intestines via the lymphatic system. The primary site of absorption for dietary cholesterol is the proximal small intestine. Cholesterol is absorbed in the intestines, binding to chylomicrons before absorption. Chylomicrons are micelles composed of a mixture of triglycerides, phospholipids, proteins, and free and esterified cholesterol.
For more complete data on the absorption, distribution, and excretion of cholesterol (6 items in total), please visit the HSDB record page.

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Metabolism/Metabolites
In animals, cholesterol itself is a precursor to bile acids, steroid hormones, and provitamin D3.
Cholesterol is a substrate for steroid biosynthesis. Cholesterol is converted to pregnenolone in cellular mitochondria, while oxidation catalyzed by P450 enzymes occurs in the smooth endoplasmic reticulum and mitochondria.Sources of cholesterol include the uptake of lipoproteins (low-density lipoprotein and high-density lipoprotein) from serum, de novo synthesis from acetate via the acetyl-CoA pathway, and the hydrolysis of cholesterol esters (CE) by neutral cholesterol ester hydrolase (nCEH). Cholesterol stored in lipid droplets mainly originates from the conversion of free cholesterol to cholesterol esters catalyzed by acyl-CoA: cholesterol acyltransferase (ACAT). In rats, very little cholesterol ester is directly absorbed from serum into the storage pool.
Cholesterol entering the rat cecum is converted into lithocholic acid and isolithocholic acid, a portion of which is excreted in feces. In guinea pigs, intestinal bacteria metabolize cholesterol into estradiol and estrone, which are then excreted in urine. Cholesterol is metabolized in the liver, primarily through the conversion into two primary bile acids: cholic acid and chenodeoxycholic acid. These bile acids, after conjugating with glycine or taurine, enter the intestine via bile, where they may be further metabolized by bacterial enzymes to produce secondary bile acids: deoxycholic acid and lithocholic acid. Cholesterol can also be converted into other neutral sterols; in the liver, reduction reactions produce cholesterol. In the intestine, the main metabolites produced by bacterial enzymes are coprostinol (a stereoisomer of cholesterol) and cholesterolone. Although both bile acids and neutral sterols undergo enterohepatic circulation, approximately 250 mg of cholesterol is net lost daily as bile acids, and approximately 500 mg is net lost daily as neutral sterols. For more complete data on the metabolism/metabolites of cholesterol (6 types), please visit the HSDB records page.

Effects During Pregnancy and Lactation
◈ What is Cholesterol?
Cholesterol is a waxy substance produced by the body that helps build healthy cells. There are two types of cholesterol: high-density lipoprotein cholesterol (HDL), often called "good" cholesterol; and low-density lipoprotein cholesterol (LDL), often called "bad" cholesterol. People also get cholesterol from certain foods. Foods rich in cholesterol include butter, fatty meats, and full-fat cheese. Lack of exercise, being overweight, and consuming high-cholesterol foods can all increase LDL cholesterol levels. Smoking lowers HDL cholesterol levels. Some people have a genetic condition called familial hypercholesterolemia (FH), which causes very high LDL cholesterol levels. People with familial hypercholesterolemia (FH) often need medication to lower their LDL cholesterol levels. High cholesterol reduces blood flow, increasing the risk of acute pancreatitis (pancreatitis) and heart disease, which can lead to heart attacks and strokes. Blood tests can detect your cholesterol levels.
◈ I have high cholesterol. Will this affect my ability to get pregnant? It's unclear whether high cholesterol affects pregnancy. One study suggests that people with high cholesterol may take longer to conceive. However, related factors such as diabetes and obesity can make pregnancy more difficult. For more information on obesity and diabetes, please see our fact sheets: https://mothertobaby.org/fact-sheets/obesity-pregnancy/ and https://mothertobaby.org/fact-sheets/diabetes-pregnancy/. ◈ I just found out I'm pregnant. Should I stop taking my cholesterol-lowering medication? Sometimes, people consider changing their medication regimen or even stopping completely after finding out they are pregnant. However, it's essential to consult your healthcare provider before changing your medication regimen. Your healthcare provider can discuss the benefits of treating your condition and the risks of not treating it during pregnancy. ◈ Will pregnancy affect my cholesterol levels? For most people, cholesterol levels drop slightly in early pregnancy but then rise. Diet, exercise, and medication use all affect cholesterol levels. If you are concerned about your cholesterol levels, consult your healthcare provider.
◈ Does high cholesterol increase the risk of miscarriage?
Miscarriage is common and can occur in any pregnancy for a variety of reasons. Based on reviewed studies, high cholesterol alone is not expected to increase the risk of miscarriage. Associated factors such as diabetes and obesity may increase the risk of miscarriage.
◈ Does high cholesterol increase the risk of birth defects?
There is a 3-5% risk of birth defects in each pregnancy, known as background risk. Based on reviewed studies, high cholesterol alone is not expected to increase the risk of birth defects above the background risk. Associated factors such as diabetes and obesity may increase the risk of birth defects.
◈ Does high cholesterol increase the risk of other pregnancy-related problems?
Based on reviewed studies, it is currently unclear whether high cholesterol increases the risk of other pregnancy-related problems. Some studies report that high cholesterol increases the risk of gestational diabetes, preeclampsia (high blood pressure during pregnancy), preterm birth (delivery before 37 weeks of gestation), or low birth weight (birth weight less than 5 pounds 8 ounces [2500 grams]). Other studies report no increase in pregnancy complications.
◈ Will high cholesterol during pregnancy affect a child's future behavior or learning?
Based on reviewed research, it is unclear whether high cholesterol causes behavioral or learning problems. Related factors such as diabetes and obesity may increase the risk of behavioral or learning problems.
◈ Can I breastfeed while taking cholesterol-lowering medication?
There are currently several medications available to treat high cholesterol. For specific information about the medications you are taking, please see our case sheet at https://mothertobaby.org/fact-sheets/ or contact MotherToBaby. Be sure to consult your healthcare provider about all breastfeeding questions.
◈ If a man has high cholesterol, will it affect fertility (the ability to impregnate a partner) or increase the risk of birth defects?
Most research on sperm quality and high cholesterol focuses on the use of cholesterol-lowering medications. High cholesterol itself may reduce the chances of conception. Generally, factors that the father or sperm donor is exposed to are unlikely to increase the risk of pregnancy. For more information, please refer to MotherToBaby's "Father Exposure" Fact Sheet at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

[1]. Cholesterol as an Endogenous ERRα Agonist: A New Perspective to Cancer Treatment. Front Endocrinol (Lausanne). 2018 Sep 11;9:525.

[2]. Thematic review series: brain Lipids. Cholesterol metabolism in the central nervous system during early development and in the mature animal. J Lipid Res. 2004 Aug;45(8):1375-97.

[3]. Effect of Cholesterol Reduction on Receptor Signaling in Neurons. J Biol Chem. 2015 Oct 30;290(44):26383-92.

Cholesterol is a cholesterane compound composed of a cholesterane with a double bond at the 5,6 positions and a 3β-hydroxyl group. It is found in humans, mice, water fleas (Daphnia galeata), and algae as a metabolite. It is a 3β-sterol, a cholesterane compound, a C27 steroid, and a 3β-hydroxy-Δ5-steroid. It is the main sterol in all higher animals, distributed in body tissues, especially the brain and spinal cord, and also present in animal fats and oils. Cholesterol has also been reported in amaranth (Acanthus ilicifolius), hybrid amaranth (Amaranthus hybridus), and several other organisms with relevant data. Cholesterol is an animal sterol found in the body tissues (and plasma) of vertebrates. It is present in high concentrations in the liver, spinal cord, and brain. Cholesterol is an important and stable component of cell membranes. It is a major precursor in the synthesis of various steroid hormones, including vitamin D, adrenocorticotropic hormone, cortisol, and aldosterone, as well as sex hormones such as progesterone, estrogen, and testosterone. Cholesterol also plays an important role in brain synapses and the immune system. In cases of elevated low-density lipoprotein (LDL) levels, cholesterol often deposits as plaques on arterial walls, a condition known as atherosclerosis, a major contributing factor to coronary heart disease and other cardiovascular diseases.
Cholesterol is the main sterol in all higher animals, distributed throughout body tissues, particularly the brain and spinal cord, and also found in animal fats and oils.
See also: Calendula (part); ox bile; cholesterol; cypress bark (ingredient). Rapid sterols (note moved to)...see more...

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Mechanism of Action
Cellular degeneration in Alzheimer's disease is mediated by a toxic mechanism involving the interaction of AβP peptide with the target cell membrane. When PC12 cells are cultured in a medium rich in surface membrane cholesterol, they become resistant to the cytotoxic effects of AβP. On the other hand, preparing cholesterol-deficient membranes by extracting cholesterol with cyclodextrin or inhibiting de novo cholesterol synthesis makes PC12 cells more susceptible to the effects of AβP. Increasing the cholesterol content of PS liposomes also inhibits AβP-dependent liposome aggregation. The authors suggest that cholesterol may regulate AβP incorporation into the cell membrane and the formation of pores by altering neuronal membrane fluidity. This view is supported by the finding that the enhanced cytotoxicity resulting from reduced cell membrane cholesterol content can be reversed by the AβP calcium channel blockers Zn2+ and tromethamine.
Therapeutic Uses

Pharmaceutical adjuvant (emulsifier).
Cholesterol is used in liposomes to encapsulate chemotherapeutic drugs and deliver them to diseased tissues.
Cholesterol-C14 is used clinically as an organ imaging agent. Organs that can be imaged by this technique include the ovary, adrenal gland, and spleen.

C27H46O

386.66

386.354

C, 83.87; H, 11.99; O, 4.14

57-88-5

Cholesterol (Water Soluble);Cholesterol-d7;83199-47-7;Cholesterol-d6;60816-17-3;Cholesterol-d6-1;92543-08-3;Cholesterol-13C2;78887-48-6;Cholesterol-d4;956029-28-0;Cholesterol myristate;1989-52-2;Cholesterol-13C5;150044-24-9;Cholesterol-13C3;Cholesterol-d;51467-57-3;Cholesterol-18O;59613-51-3

5997

White to off-white solid

1.0±0.1 g/cm3

360 ºC

148-150 °C

250 ºC

0.0±2.7 mmHg at 25°C

1.525

Endogenous Metabolite

9.85

1

1

5

28

591

8

O([H])[C@@]1([H])C([H])([H])C([H])([H])[C@@]2(C([H])([H])[H])C(C1([H])[H])=C([H])C([H])([H])[C@]1([H])[C@]2([H])C([H])([H])C([H])([H])[C@]2(C([H])([H])[H])[C@@]([H])([C@]([H])(C([H])([H])[H])C([H])([H])C([H])([H])C([H])([H])C([H])(C([H])([H])[H])C([H])([H])[H])C([H])([H])C([H])([H])[C@]21[H]

HVYWMOMLDIMFJA-DPAQBDIFSA-N

InChI=1S/C27H46O/c1-18(2)7-6-8-19(3)23-11-12-24-22-10-9-20-17-21(28)13-15-26(20,4)25(22)14-16-27(23,24)5/h9,18-19,21-25,28H,6-8,10-17H2,1-5H3/t19-,21+,22+,23-,24+,25+,26+,27-/m1/s1

(3S,8S,9S,10R,13R,14S,17R)-10,13-dimethyl-17-((R)-6-methylheptan-2-yl)-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol

AI3 03112 CCRIS 2834; AI303112; AI3-03112

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Ethanol : ~20 mg/mL (~51.73 mM)
DMSO :< 1 mg/mL

Solubility in Formulation 1: ≥ 1.43 mg/mL (3.70 mM) (saturation unknown) in 10% EtOH + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 14.3 mg/mL clear EtOH stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 1.43 mg/mL (3.70 mM) (saturation unknown) in 10% EtOH + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 14.3 mg/mL clear EtOH stock solution to 900 μL of corn oil and mix well.

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 (Please use freshly prepared in vivo formulations for optimal results.)