Roxibolone (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

) (developmental code name BR-906), also known as 11β,17β-dihydroxy-17α-methyl-3-oxoandrosta-1,4-diene-2-carboxylic acid, is a

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

antiglucocorticoid An antiglucocorticoid is a drug which reduces glucocorticoid activity in the body. They include direct glucocorticoid receptor antagonists such as mifepristone and synthesis inhibitors such as metyrapone, ketoconazole, and aminoglutethimide. T ...

described as an

anticholesterolemic Lipid-lowering agents, also sometimes referred to as hypolipidemic agents, cholesterol-lowering drugs, or antihyperlipidemic agents are a diverse group of pharmacology, pharmaceuticals that are used to lower the level of lipids and lipoproteins such ...

(

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell membr ...

-lowering) and

anabolic Anabolism () is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-d ...

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhal ...

which was never marketed. Roxibolone is closely related to

formebolone Formebolone (INN, BAN) (brand names Esiclene, Hubernol, Metanor), also known as formyldienolone, as well as 2-formyl-11α-hydroxy-17α-methyl-δ1-testosterone, is an orally active anabolic-androgenic steroid (AAS) described as an anticatabolic an ...

, which shows antiglucocorticoid activity similarly and, with the exception of having a carboxaldehyde

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

at the C2 position instead of a

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxyl ...

group, roxibolone is structurally almost identical to. The 2- decyl

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

of roxibolone, decylroxibolone (developmental code name BR-917), is a long-acting prodrug of roxibolone with similar activity. In rats, roxibolone counteracts the

catabolic Catabolism () is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysaccharides, lipids ...

effects (control of

nitrogen balance Nitrogen balance is a measure of nitrogen input minus nitrogen output. Nitrogen Balance = Nitrogen intake - Nitrogen loss Sources of nitrogen intake include meat, fish, dairy foods, eggs, nuts and legumes, and grains and cereals. Examples of nitr ...

) and increased alkaline phosphatase levels induced by the potent

glucocorticoid Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every verte ...

dexamethasone phosphate Dexamethasone is a glucocorticoid medication used to treat rheumatic problems, a number of skin diseases, severe allergies, asthma, chronic obstructive lung disease, croup, brain swelling, eye pain following eye surgery, superior vena cav ...

. It does not bind to the

glucocorticoid receptor The glucocorticoid receptor (GR, or GCR) also known as NR3C1 (nuclear receptor subfamily 3, group C, member 1) is the receptor to which cortisol and other glucocorticoids bind. The GR is expressed in almost every cell in the body and regulates ...

however, and its antiglucocorticoid activity may instead be mediated by

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

inhibition Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...

. In accordance, 11α- and

11β-hydroxyprogesterone 11β-Hydroxyprogesterone (11β-OHP), also known as 21-deoxycorticosterone, as well as 11β-hydroxypregn-4-ene-3,20-dione, is a naturally occurring, endogenous steroid and derivative of progesterone. It is a potent mineralocorticoid. Syntheses of 1 ...

are known to be potent

inhibitor Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...

s of 11β-hydroxysteroid dehydrogenase (11β-HSD), which is responsible for the biosynthesis of the potent

endogenous Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, ...

glucocorticoids

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal g ...

and

corticosterone Corticosterone, also known as 17-deoxycortisol and 11β,21-dihydroxyprogesterone, is a 21-carbon steroid hormone of the corticosteroid type produced in the cortex of the adrenal glands. It is of minor importance in humans, except in the very ra ...

(from the

precursor Precursor or Precursors may refer to: *Precursor (religion), a forerunner, predecessor ** The Precursor, John the Baptist Science and technology * Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of un ...

deoxycortisol Deoxycortisol may refer to: * 11-Deoxycortisol (cortodoxone, cortexolone, Reichstein's Substance; 17α,21-dihydroxyprogesterone) * 17-Deoxycortisol (corticosterone; 11β,21-dihydroxyprogesterone) * 21-Deoxycortisol (11β,17α-dihydroxyprogesterone ...

and

deoxycorticosterone Deoxycorticosterone (DOC), or desoxycorticosterone, may refer to: * 11-Deoxycorticosterone (21-hydroxyprogesterone) * 21-Deoxycorticosterone (11β-hydroxyprogesterone) See also * Deoxycortisol * Deoxycortisone * 11-Hydroxyprogesterone 11-Hydroxyp ...

, respectively). As roxibolone is 11β-hydroxylated similarly, it may act in a likewise fashion. However, formebolone was found to be a very weak inhibitor of 11β-HSD type 2, although this specific

isoenzyme In biochemistry, isozymes (also known as isoenzymes or more generally as multiple forms of enzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters (e.g. dif ...

is responsible for the inactivation of glucocorticoids rather than their production. Unlike formebolone, which is additionally an

anabolic-androgenic steroid Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroidal androgens that include natural androgens like testosterone as well as synthetic androgens that are structurally related and have similar effects t ...

(AAS), roxibolone is devoid of

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Part ...

for the androgen receptor and possesses no

androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...

ic or myotrophic activity in

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

assay An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of ...

s. For this reason, it has been said that roxibolone may be much better tolerated in comparison.

References

Androstanes Antiglucocorticoids Carboxylic acids Hypolipidemic agents Ketones {{systemic-hormonal-drug-stub