Domestic auto sales were 23.5 percent lower in mid-April than in the comparable period a year ago, the seven major U.S. car makers reported yesterday.

Analysts cautioned that the comparison was exaggerated because the sales rate had approached record levels in the April 11 through 20 period of 1985. They said the car makers actually had a fair showing this time.

"Last year was exceptionally strong and that made this year's sales look worse than they really were," said automotive analyst Gary Glaser of First Boston Corp. in New York.

Industry leader General Motors Corp. had a 22.3 percent decline during the period compared with a year ago. Ford Motor Co. sales were down 29.8 percent and Chrysler Corp.'s were off 20.8 percent.

Glaser said GM's sales may have been bolstered by buyers trying to beat the deadline for the company's 2.9 percent price increase, which went into effect with factory shipments April 14.

Among the smaller domestic producers, American Honda Motor Co. Inc. sales of Ohio-made cars rose 16.4 percent in the period, the only year-to-year gain reported. American Motors Corp. sales were down 47.5 percent and Volkswagen of America Inc. sales were down 11.3 percent. Nissan Motor Corp. USA sold 1,058 cars in the period compared with 573 a year ago, its first period of car production in Tennessee.