I am related to a large Parker family, although I don't recall an Isaac Parker. It's too bad you don't have any additional information. I was thinking that since my Great(2) Grandfather Dr. Peter James Parker was tenth of twelve children, and his father Rev. Peter Parker was fifth of fourteen, that this could be a distant relative.
Donald, here is a link to a list of Parker's that Isaac Parker is related to. Hope it helps. http://familytreemaker.genealogy.com/users/s/c/h/Arlene-M-Schwenke/index.html