19-Norandrostenedione
Encyclopedia
19-Norandrostenedione is a precursor of the anabolic steroid
nandrolone
. Until 2005 19-Norandrostenedione was available without prescription in United States, where it was marketed as a prohormone
, but it is now classified as a Schedule III drug. 19-Norandrostenedione is readily metabolized to nandrolone after oral administration, but its potency to transactivate the androgen receptor
dependent reporter gene expression is 10 times lower as compared to dihydrotestosterone
(DHT).
In vivo experiments in castrated rats demonstrated that subcutaneous treatment with 19-norandrostenedione resulted only in a stimulation of the weight of the levator ani
muscle, while the prostate
and seminal vesicle weights remained completely unaffected. In contrast to its metabolite nandrolone, 19-norandrostenedione highly selectively stimulates the growth of the skeletal muscle
s but has only weak androgenic properties.
In the early 2000s, contamination of androstenedione
products with traces of 19-norandrostenedione caused false positives for doping
tests for nandrolone
because 19-norandrosterone
is a metabolite of both nandrolone
and 19-norandrostenedione. In a randomized controlled trial
trace contamination of androstenedione
with 19-norandrostenedione was sufficient for users of androstendione to test positive for nandrolone. This detail became less relevant after androstenedione
itself was banned by major sporting bodies.
Anabolic steroid
Anabolic steroids, technically known as anabolic-androgen steroids or colloquially simply as "steroids", are drugs that mimic the effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue ,...
nandrolone
Nandrolone
Nandrolone is an anabolic steroid that may be present naturally in the human body, albeit in minute quantities of less than 0.4 ng/ml. Nandrolone is most commonly sold commercially as its decanoate ester and less commonly as a phenylpropionate ester...
. Until 2005 19-Norandrostenedione was available without prescription in United States, where it was marketed as a prohormone
Prohormone
A prohormone is a substance that is a precursor to a hormone, usually having minimal hormonal effect by itself. The term has been used in medical science since the middle of the 20th century. The primary function of a prohormone is to enhance the strength of the hormone that already occurs in the...
, but it is now classified as a Schedule III drug. 19-Norandrostenedione is readily metabolized to nandrolone after oral administration, but its potency to transactivate the androgen receptor
Androgen receptor
The androgen receptor , also known as NR3C4 , is a type of nuclear receptor that is activated by binding of either of the androgenic hormones testosterone or dihydrotestosterone in the cytoplasm and then translocating into the nucleus...
dependent reporter gene expression is 10 times lower as compared to dihydrotestosterone
Dihydrotestosterone
Dihydrotestosterone is an androgen or male sex hormone. The enzyme 5α-reductase synthesises DHT in the prostate, testes, hair follicles, and adrenal glands...
(DHT).
In vivo experiments in castrated rats demonstrated that subcutaneous treatment with 19-norandrostenedione resulted only in a stimulation of the weight of the levator ani
Levator ani
The levator ani is a broad, thin muscle, situated on the side of the pelvis.It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity....
muscle, while the prostate
Prostate
The prostate is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals....
and seminal vesicle weights remained completely unaffected. In contrast to its metabolite nandrolone, 19-norandrostenedione highly selectively stimulates the growth of the skeletal muscle
Skeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...
s but has only weak androgenic properties.
In the early 2000s, contamination of androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
products with traces of 19-norandrostenedione caused false positives for doping
Doping (sport)
The use of performance-enhancing drugs in sport is commonly referred to by the term "doping", particularly by those organizations that regulate competitions. The use of performance enhancing drugs is mostly done to improve athletic performance. This is why many sports ban the use of performance...
tests for nandrolone
Nandrolone
Nandrolone is an anabolic steroid that may be present naturally in the human body, albeit in minute quantities of less than 0.4 ng/ml. Nandrolone is most commonly sold commercially as its decanoate ester and less commonly as a phenylpropionate ester...
because 19-norandrosterone
19-Norandrosterone
19-Norandrosterone is a nandrolone and 19-norandrostenedione metabolite. It is created as a byproduct of nandrolone via the 5-alpha reductase enzyme and is on the list of substances prohibited by the World Anti-Doping Agency since it is a detectable metabolite of nandrolone which is an anabolic...
is a metabolite of both nandrolone
Nandrolone
Nandrolone is an anabolic steroid that may be present naturally in the human body, albeit in minute quantities of less than 0.4 ng/ml. Nandrolone is most commonly sold commercially as its decanoate ester and less commonly as a phenylpropionate ester...
and 19-norandrostenedione. In a randomized controlled trial
Randomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
trace contamination of androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
with 19-norandrostenedione was sufficient for users of androstendione to test positive for nandrolone. This detail became less relevant after androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
itself was banned by major sporting bodies.