No executive director of the intermediate unit, district, or assistant district superintendent or assistant executive director of an intermediate unit in this Commonwealth shall engage in the business or profession of teaching in this Commonwealth, unless it is done without any other compensation than that paid to him as such superintendent: Provided, That he may receive compensation for services in a summer school, maintained in a State college or university, or other college or university, devoted to the training of teachers, or for services rendered evenings or Saturdays during the school term, to any such college or university, if he is released for such service by the board of school directors of the district in which he is employed.
24 P.S. § 10-1007