Can dreams be memorised?
I don't know how it is when it goes about hormones but for sure dreams can be remembered and this remembering of dreams can be improved.

One of the most popular methods is trying to think about somebody's dreams just after waking up. It is also important to tell it loudly, record it or write it down.
After some time (even few days) of writing down your dreams a person is able to remember not one, but two, three or more dreams from one night.

The case of getting access to your previous dreams lately is connected with lucid dreaming - if you are able to have lucid dreams whenever you want, you also can initiate these situations which you like. But it is much less scientifically described case.