Performances by two regional companies, Communications Satellite Corp. and Reynolds Metals Corp., fell along industry lines yesterday, with Reynolds posting a substantial loss and Comsat showing a 22 percent increase in earnings.

Comsat had a consolidated first-quarter net income of $12.6 million ($1.40 a share), representing a $2.3 million increase over $10.3 million ($1.29) a year ago.

The District-based company attributed the increase in earnings to the continued growth from Comsat's international satellite services. However, these revenue increases were in part offset by Comsat's participation in Satellite Business Systems, the McLean-based joint venture of Comsat, International Business Machines Corp. and Aetna Life & Casualty Co. The quarterly loss from Comsat's share in SBS increased to $5.5 million this first quarter from $4.7 million in losses from the first quarter of 1982.

Operating revenues for the first quarter were $108.4 million compared with $94.1 million in the first quarter of 1982.

Reynolds, the giant aluminum company based in Richmond, reported that it suffered a first-quarter net loss of $52.4 million, representing a $2.71 drop in the value of a share. David P. Reynolds, Reynolds' chairman and chief executive officer, attributed the drop to weak margins due to continuing cost pressures.

The loss compares to net income of $13.6 million (68 cents a share) for the first quarter last year. The company's net first-quarter sales dropped from $749 million in 1982 to $746.9 million this year.