International Paper Co. said yesterday it earned $1.80 a share from continuing operations in the first quarter compared with $3.72 a year ago, which included $1.99 a share on the sale of a mill at Panama City, Fla.

Net income was $89 million on sales of $1.237 billion compared with $177.6 million a year ago on sales of $1.066 billion.

Chairman Dr. Edwin A. Gee said shipments were strong during the quarter in all lines except lumber and plywood.

Method-Goldwyn-Myer Inc. said yesterday it earned $10.2 million (31 cents a share) in its second fiscal quarter ended last Feb. 29, down from $10.4 million (33 cents) in the same period the previous year.

For the first half, MGM profits totaled $25.5 million (78 cents) on operating revenues of $243.5 million.

MGM earned $36.4 million ($1.13) in the first half of fiscal 1979, including $15.4 million (48 cents) from the licensing of domestic television rights to the movie "Gone With the Wind." Operating revenues in the fiscal 1979 period were $254.6 million.

Dow Jones & Co., publisher of The Wall Street Journal, said yesterday its net income in the first quarter rose nearly 12 percent from the same 1979 period as advertising and circulation revenues showed strong gains.

Dow Jones said it earned $11.9 million (77 cents a share) in the quarter on sales of $120.3 million. In the first quarter of 1979, net income totaled $10.7 million (69 cents) on sales of $98.2 million.