Since the research on Preg and humans is limited, we'll have to rely
on animal studies for the time being. Significantly lower levels of
pregnenolone were found in certain parts of the brain (especially the
hippocampus) in aged rats with poor performance in memory tasks
compared with aged rats with higher levels of Preg in their brain.
Furthermore, when the rats were given injections of Preg, their
deficit was temporary corrected. The researchers state, "It is
proposed that the hippocampal content of Preg plays a physiological
role in preserving and/or enhancing cognitive abilitites in old
animals, possibly via an interaction with central cholinergic systems.
Thus neurosteroids should be further studied in the context of
prevention and/or treatment of age-related memory disorders.
Vallee M, Mayo W, Darnaudery M, Corpechot C, Young J, Koehl M, Le
Moal M, Baulieu EE, Rober P, Simon H. Neurosteroids: deficient
cognitive performance in aged rats depends on low pregnenolone sulfate
levels in the hippocampus. Proc Natl Acad Sci USA
23;94(26):14865-14870, 1997.