Chemistry
Progesterone is a naturally occurring pregnane steroid and is also known as pregn-4-ene-3,20-dione. It has a double bond (4-ene) between the C4 and C5 positions and two ketone groups (3,20-dione), one at the C3 position and the other at the C20 position. Due to its pregnane core and C4(5) double bond, progesterone is often abbreviated as P4. It is contrasted with pregnenolone, which has a C5(6) double bond and is often abbreviated as P5. Derivatives
A large number of progestins, or synthetic progestogens, have been derived from progesterone. They can be categorized into several structural groups, including derivatives of retroprogesterone, 17α-hydroxyprogesterone, 17α-methylprogesterone, and 19-norprogesterone, with a respective example from each group including dydrogesterone, medroxyprogesterone acetate, medrogestone, and promegestone. The progesterone ethers quingestrone (progesterone 3-cyclopentyl enol ether) and progesterone 3-acetyl enol ether are among the only examples that do not belong to any of these groups. Another major group of progestins, the 19-nortestosterone derivatives, exemplified by norethisterone (norethindrone) and levonorgestrel, are not derived from progesterone but rather from testosterone.A variety of synthetic inhibitory neurosteroids have been derived from progesterone and its neurosteroid metabolites, allopregnanolone and pregnanolone. Examples include alfadolone, alfaxolone, ganaxolone, hydroxydione, minaxolone, and renanolone. In addition, C3 and C20 conjugates of progesterone, such as progesterone carboxymethyloxime (progesterone 3-(O-carboxymethyl)oxime; P4-3-CMO), P1-185 (progesterone 3-O-(L-valine)-E-oxime), EIDD-1723 (progesterone 20E-[O-[(phosphonooxy)methyl]oxime] sodium salt), EIDD-036 (progesterone 20-oxime; P4-20-O), and VOLT-02 (chemical structure unreleased), have been developed as water-soluble prodrugs of progesterone and its neurosteroid metabolites. Synthesis
Chemical syntheses of progesterone have been published. History
Discovery and synthesis
The hormonal action of progesterone was discovered in 1929.
These are nearly always done in a single setting (or stage).In the penile urethra, anastomotic urethroplasties are rare because they can lead to chordee (penile curvature due to a shortened urethra). Instead, most penile urethroplasties are substitution procedures utilizing buccal mucosa graft, full-thickness skin graft, or split-thickness skin graft. These can be done in one or more settings, depending on stricture location, severity, cause and patient or surgeon preference. Urethral stent
A permanent urethral stent was approved for use in men with bulbar urethral strictures in 1996, but was recently removed from the market.A temporary thermoexpandable urethral stent (Memotherm) is available in Europe but is not currently approved for use in the United States. Emergency treatment
When in acute urinary retention, treatment of the urethral stricture or diversion is an emergency. Options include:

Urethral dilatation and catheter placement. This can be performed in the Emergency Department, a practitioners office or an operating room. The advantage of this approach is that the urethra may remain patent for a period of time after the dilation, though long-term success rates are low. Insertion of a suprapubic catheter with catheter drainage system. This procedure is performed in an Operating Room, Emergency Department or practitioners office. The advantage of this approach is that it does not disrupt the scar and interfere with future definitive surgery. Ongoing care
Following urethroplasty, patients should be monitored for a minimum of 1 year, since the vast majority of recurrences occur within 1 year.