In contrast, the pregnenolone sulfate level was low and its change was less pronounced.

Levels of pregnenolone in serum were reduced in parallel.

All of these hormones are made from a hormone called pregnenolone, which is made from cholesterol.

In both sexes, pregnenolone concentrations in the brain were almost constant during the seasonally breeding cycle.

Studies in rats and humans suggest that giving pregnenolone enhances the ability to learn and enhances memory.

In contrast, the pregnenolone sulfate ester level was low and did not significantly change among the developmental stages.

It has been reported that CS regulates progesterone and pregnenolone production in the placenta, adrenal glands and ovary.

Progesterone concentrations in the brain, which were lower than pregnenolone levels, also showed peaks in April and August.

These results taken together suggest that the amphibian brain possesses steroidogenic enzyme P450scc and produces pregnenolone and its sulfate ester.

The steroid pregnenolone (P) and its sulfate (PS) can accumulate in the central nervous system independent of peripheral sources.

Employing biochemical techniques combined with HPLC analysis, the conversion of pregnenolone to progesterone was found in brain slices of mature males.

In the present study, seasonal changes in pregnenolone and its sulfate ester were further examined as a possible physiological change using R. nigromaculata.

A specific RIA indicated that the pregnenolone concentration was unexpectedly high at 0 day and decreased until 7 days.

The triterpenoid fraction inhibited both the type I pregnenolone- and progesterone-induced difference spectra and elicited a type II difference spectrum in the absence of substrate.

A flurry of research was done on pregnenolone in the 1940s, but the only clear effect it had was in relieving symptoms of rheumatoid arthritis.

The inhibition of binding of pregnenolone to CYP17 by the chloroform extract was 62%, with negligible inhibition by the methanol extract.