Function with Transaction Problem

###### FUNCTION   DOES WORK  (FUNCIONA)
DELIMITER |
CREATE OR REPLACE FUNCTION TesteFunction() RETURNS INT DETERMINISTIC MODIFIES SQL DATA
BEGIN
    DECLARE Retorno INT;

    UPDATE Produto SET CD_Extra = "CD00472-5" WHERE CD_Codigo = 6;
    SELECT ROW_COUNT() INTO Retorno;

    RETURN Retorno;
END |


###### PROCEDURE WITH TRANSACTION   DOES WORK  (FUNCIONA)
DELIMITER |
CREATE OR REPLACE PROCEDURE TesteFunction() DETERMINISTIC MODIFIES SQL DATA
BEGIN
    START TRANSACTION READ WRITE;
    UPDATE Produto SET CD_Extra = "CD00472-5" WHERE CD_Codigo = 6;
    SELECT ROW_COUNT();
    COMMIT;
END |


###### FUNCTION WITH TRANSACTION   DOESN'T WORK  (NÃO FUNCIONA)
DELIMITER |
CREATE OR REPLACE FUNCTION TesteFunction() RETURNS INT DETERMINISTIC MODIFIES SQL DATA
BEGIN
    DECLARE Retorno INT;

    START TRANSACTION READ WRITE;
    UPDATE Produto SET CD_Extra = "CD00472-5" WHERE CD_Codigo = 6;
    SELECT ROW_COUNT() INTO Retorno;
    COMMIT;

    RETURN Retorno;
END |