No member of the board shall have an interest, direct or indirect, in the gains or profits of any investment made by the board, save insofar as any such member may be a member of the retirement system, and no member of the board shall receive directly or indirectly, any payment or emolument for his services except as expressly provided in this chapter. No member of the board shall, directly or indirectly, for himself or as an agent, in any manner use the funds or deposits of the retirement system, except to make such payments therefrom as are authorized by the board, nor shall any member become an indorser or surety or in any manner an obligor for moneys loaned by or borrowed from the board.
T.C.A. § 8-4006