A Japan Highway Public Corp. director was entertained by some 10 banks and securities companies, including Nomura Securites Co., to the tune of about 10 million yen, it was learned Tuesday from statements made by those involved.Tekehiko Isaka, 54, was allegedly entertained by the firms over a 2 1/2 year period from July 1994 when he entered the public corporation, according to sources. The sources also revealed that among those who entertained Isaka, a former Ministry of Finance official, Nomura spent the most, followed by the Industrial Bank of Japan.Nomura Securities Co. was made the joint lead underwriter for a 1996 government bond issue -- a decision that the sources allege was made by Isaka even before official selection procedures had begun. Isaka was in charge of accounting at the state-run corporation before his arrest Sunday on suspicion of receiving bribes worth 2.58 million yen from Nomura between July 1994 and December 1995.He informed Nomura of the highway corporation's decision in August 1996, bypassing specified selection procedures, the sources alleged. He is also suspected of illegally informing Nomura about the highway corporation's desired terms for its bond issue in September 1994.In November 1996, Nomura and Sakura Bank's overseas subsidiaries were officially chosen as joint lead underwriters for the highway corporation's foreign currency-denominated bonds, issued at $300 million in Europe. According to the sources, the lead underwriter for the corporation's foreign bond issue is supposed to be selected from among several banks and brokerages, taking into consideration such factors as proposed conditions for issuing the bonds and the trustworthiness and performance record of the candidate firms.For the 1996 issue, banks and securities houses were asked to submit bond-issuance proposals as a formality after Nomura was informed of its selection as joint lead underwriter, the sources said. Investigators also suspect that Isaka leaked information to Nomura on desired conditions for the 1996 bond issuance, the sources said.Prosecutors suspect Isaka received the bribes -- mainly in the form of wining, dining and golf outings -- between July 1994 and December 1995. They have also arrested Naotaka Murasumi, 57, a former Nomura vice president, and Isao Teranishi, 50, a former Nomura managing director, on suspicion of involvement in bribing Isaka.Japan Highway officials are considered public servants under the Japan Highway Public Corp. Law and are subject to bribery charges. The corporation is under the control of the Construction Ministry and operates a vast network of expressways across Japan.