Progesterone 11-keto derivatives

Thresholds of the olfactory receptors of male goldfish are 35 pg/ml water for the prostaglandin F2a, and 100 times less for its 15-keto-derivative. The males receptor threshold for 17,20-progesterone (from females) is a tiny fraction of 1 pg/ml water. Three grams (one teaspoonful) would provide an abovethreshold stimulus when diluted in 500 x 500 x 500 m water (Bjerselius and Olsen, 1993). In lampreys, testosterone from males attracts females at a concentration of 29 pg/ml water but urine with a testosterone concentration of 29 X 10 pg/ml is active (Adams etal., 1987). 

Higashi and coworkers [28] used 2-hydrazino-l-methylpyridine (HMP) derivatization to introduce a positively charged moiety in testosterone and dihydrotestosterone (DHT) to achieve a sensitivity improvement of 70- to 1600-fold compared to underivatized molecules in ESI. However, they found the derivative was unsuitable for di-keto steroids such as androstenedione and progesterone, so this form of derivatization is unlikely to be widely accepted. Separable syn- and anti- (E and Z) stereoisomers are formed using this derivative. Preparation is as follows a solution of 10 pg HMP in 50 pi ethanol containing 25 pg TFA was added to the steroid dissolved in 30 pi ethanol. After heating for 1 h at 60 C, the solvents can be removed and sample injected. 

As indicated above, most authors agree that 20a-dihydroprogesteronc is the principal metabolic product of progesterone in the human placenta (Zander el al., 1958 Little et al., 1959 Zander, 1964), and it is now well established that the reduction of the 20-keto function of progesterone to the corresponding 20-dihydro derivatives is stercospccific and the main compound obtained is the 20a-isomer. This transformation is reversible... 

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