The Nebraska Investment Council may give priority to the investments authorized by section 72-1246.01 and shall liquidate other investments if necessary to meet the demand for such loans; Provided, that any investments made prior to May 24, 1971, may be retained in kind, notwithstanding the provisions of section 72-1246, until such time as in the discretion of the Nebraska Investment Council the same may be sold for the best advantage of the retirement fund. All interest received on such loans shall be credited to the fund from which the loan was made.