GULF AND WESTERN <GW> UPS INTEREST IN NETWORK USA Network, today said it has acquired Time Inc's <TL> one-third interest in the network. The network, formerly a joint venture between Time, Gulf and Western Inc and MCA Inc <MCA>, said that Gulf and Western and MCA, who each previously held a one-third interest, now will jointly own USA Network on a 50/50 basis. Terms were not disclosed, USA Network said. USA Network is an advertiser-supported, entertainment basic cable network, reaching 39 mln homes on 8,500 cable systems.