Litton Industries Inc. has sold about 75 percent of its local biotechnology subsidiary, Litton Bionetics, and is negotiating with Hazelton Laboratories Corp. for sale of the remaining operations.

Litton Bionetics, based in Kensington, was among the first companies licensed to develop, manufacture and sell diagnostic tests for the antibodies to the virus associated with acquired immune deficiency syndrome (AIDS). The company's various biological research, testing and sales operations employ about 800 workers and generate sales of about $40 million a year, said Robert S. Knapp, a spokesman for Litton Industries.

No purchase prices were disclosed.

Litton Industries, based in Beverly Hills, Calif., has three core businesses: advanced electronics and defense systems, industrial automation systems and geophysics services. The company decided to sell the biotech unit because it "just doesn't fit" with the core businesses, Knapp said.

About half of Bionetics' business has been purchased by Organon Teknika, a subsidiary of Akzo Pharma, which is the pharmaceutical unit of Akzo N.V., based in Arnhem, the Netherlands. The Dutch company acquired operations involved in the research, development and manufacture of human and veterinary diagnostic products, which includes the division marketing the AIDS antibodies test.

Organon Teknika's acquisition included operations involved in developing agents for modulating the immune system and government contracts for cancer research.

Those operations together account for about $20 million in annual sales and employ about 400 workers in Kensington, Rockville and Charleston, S.C.

James C. Nance, president of Litton Bionetics, has assumed a "senior management position" with the Dutch company, Knapp said.

About 25 percent of Litton Bionetics has been sold to MetPath Inc., based in Teeterboro, N.J. A subsidiary of Corning Glass Works, MetPath bought Litton's mid-Atlantic network of clinical laboratories and a complex of chemical analysis equipment. The laboratories perform routine analysis of biological samples for physicians and hospitals. The lab and equipment operations account for sales of about $10 million a year, and have about 300 employes.

Litton Industries is discussing the sale of the remaining 25 percent of Bionetics' business to Hazelton Laboratories, based in Vienna, Va. Hazelton provides biological and chemical research services, manufactures laboratory and medical products, and is a major supplier of research animals.

No timetable has been set for completing the sale, Knapp said.