POINDEXTER DEFENDS REAGAN'S CREDIBILITY.(Main)

Byline: Charles Green and R.A. Zaldivar Knight-Ridder

An unrepentant John M. Poindexter told the congressional Iran-contra committees Monday that he has no regrets about his actions as national security adviser and said that President Reagan's credibility has not been damaged by the eight months of controversy over the Iran-contra affair.

Confronted with sharp criticism of what one GOP legislator termed his "unapologetic embrace of untruths," Poindexter defended himself with the most passion he has displayed during four days of testimony.

"I don't have any regrets for anything that I did. I think the actions that I took were in the long-term interests of the country, and I'm not going to change my mind," said Poindexter, his voice rising. "And I'm not going to be apologetic about it."

The outburst was triggered by Sen. Paul Trible, R-Va., who suggested that Poindexter, a rear admiral, had not abided by the Naval Academy honor code's provision against evasive or misleading statements. Trible's criticism, along with his accusation that Poindexter embraced untruths, prompting Poindexter to heatedly reply: "I have always lived by the honor concept. I still …