Washington real estate investor Conrad Cafritz this week sought bankruptcy protection for six of his more than 100 partnerships, the first major setback in his campaign to solve his financial problems out of court.

Cafritz took the action after the State Teachers Retirement System of Ohio, a teachers pension fund, initiated foreclosure proceedings against warehouses owned by the partnerships. The pension fund lent the Cafritz partnerships about $25 million last year to finance the warehouses, but the partnerships defaulted on the loan.

"It's not a big deal," a spokesman for the Cafritz partnerships said yesterday.

Since last spring, Cafritz has been asking most of his lenders to relax repayment terms while he attempts to sell or restructure his holdings. He has debts of about $1.1 billion with 71 lenders, according to a report from Cafritz to his creditors.

The bankruptcy filing Tuesday at the U.S. Bankruptcy Court in the District was Cafritz's first since he disclosed last spring that he was running short of cash. The bankruptcy filing temporarily blocked the foreclosure and began what can be a long and costly process to reorganize the partnerships under the supervision of a judge.

Cafritz has told his creditors that they could recoup more of their money if they would give him at least until 1993 to sell or restructure his holdings instead of forcing the immediate sale of the real estate at depressed prices. He has urged them to avoid the expense of taking their differences to court.

Cafritz has been more successful with a number of other creditors, most notably with his largest, Helsinki-based Skopbank. Skopbank, which already had lent Cafritz $87.8 million, recently agreed to lend him another $110 million, sources said.

Before the bankruptcy filings, some of Cafritz's bankers had expressed concern that if one major lender tried to foreclose, it could prompt others to take similar action and undermine Cafritz's effort to negotiate a collective repayment plan with his creditors. It was not clear yesterday how the bankruptcy filings would affect the thinking of Cafritz's other creditors, if at all.

Creditors have formed a committee to consider the repayment plan Cafritz has proposed. Representatives of the committee could not be reached for comment yesterday.

Cafritz declined to comment on the bankruptcy filings, but a spokesman for the partnerships said Cafritz did not personally guarantee the Ohio pension fund's loan. As a result, the pension fund has claims only to the six warehouses it financed in Virginia and Maryland, not to Cafritz's other wealth.

That means that the pension fund is not directly competing with other lenders to get money from Cafritz. Indirectly, though, the bankruptcy could deny Cafritz funds he could have used to help repay other creditors. Cafritz's strategy has been to use any profits he can raise by selling properties like the warehouses to help repay other lenders.

The Cafritz spokesman said Cafritz is still in negotiations with the State Teachers Retirement System of Ohio. "We have no idea whether they'll be successful or not," the spokesman said.

Cafritz bought the six warehouses during the past two years and then combined them under one loan from the pension fund. Some of the warehouses have been generating enough rental income to cover debts, but others have not, a source said. The rent from the warehouses was being paid directly to the pension fund, even before it prepared to foreclose, instead of to Cafritz's organization, which normally received the payments.