ENDOTRONICS <ENDO> TARGET OF INVESTIGATION Endotronics Inc said it is the target of a formal private investigation by the Securities and Exchange Commission as well as the Federal Bureau of Investigation. The company also said its independent accounts, Peat, Marwick, Mitchell and Co, served notice that its report on Endotronics' financial statements as of Sept 30, 1986 and for the year then ended should no longer be relied upon. Endotronics said the notice from its accountants stated "we cannot satisfy ourselves as to the true facts of the situation to a degree necessary to continue to be associated with such consolidated financial statements." Endotronics recently reported that it was reviewing the need to establish a reserve for all or a portion of approximately 3,686,000 dlrs in overdue accounts receivable and to assess the impact, if any, on prior period financial statements in light of a dispute with one of its Japanese distributors over payment of the overdue accounts. Endotronics said it was providing documentation to the Securities and Exchange Commission in connection with that agency's investigation. It also said Michael Gruenberg resigned from the company's board of directors.