NEW YORK, April 7 (Reuters) - ProLogis (PLD.N: Quote, Profile, Research), an owner and developer of warehouses, said on Tuesday that it would offer to sell 115 million shares as part of several initiatives to strengthen its balance sheet.

ProLogis shares rose to $7.10 in after-hours trading, up 4 percent from its New York Stock Exchange close of $6.82.

As part of the equity offering, the company said it plans to grant the underwriters a 30-day option to buy up to 17.25 million additional shares to cover overallotments.

ProLogis said it would use net proceeds from the sale to reduce borrowings under its global line of credit and for general corporate purposes.

ProLogis also said that PLD International Finance LLC, its wholly owned, indirect subsidiary had agreed to buy about 42.65 million euro ($57.6 million) principal amount of notes due April 2011 for a discount price of 32.0 million euro (US$43.2 million).

The company said it had repurchased $162.8 million original principal amount of its convertible notes for about $12.0 million and $141.1 million of its 1.875 percent convertible senior notes for $72.3 million.

"Between our Eurobond tender launched last week and the repurchase of convertible debt at discounts to the principal amount, we have repurchased more than $220 million of senior notes and reduced our on-balance sheet debt by more than $94 million in recent weeks," ProLogis' Chief Executive Walter Rakowich said in a statement.

The company is negotiating with various lenders for about $344 million in new secured borrowings in the United States. It also is targeting new secured debt financings in Japan and is in discussions with its bank group to restructure its global line of credit. (Reporting by Ilaina Jonas)