The lira was trading flat and Istanbul's main share index was just below flat following weakness in Asian markets.
Turkey's two-year benchmark bond yield stood at 7.41 percent, slightly up from Wednesday's close of 7.39 percent.
"Next week's debt auctions prevent bond yields from falling further. We don't expect the benchmark bond yield to decline below 7.25 percent ahead of the auctions," wrote analysts at Halk Invest.
On Sept. 24, the Turkish treasury will issue a 10-year fixed-coupon bond.
On Sept. 25, it will tap a one-year zero-coupon bond and issue a two-year fixed-coupon bond, which is expected to be the new two-year benchmark bond.
Investors were selling bonds ahead of the debt auctions, on prospects that demand for the new paper will reduce the volume of trade in the old benchmark.
Istanbul's main share index was 0.85 down percent, in line with a 1.11 percent fall in the MSCI emerging markets index.
Shares in Olmuksa, a unit of Turkey's Sabanci Holding, were up 4.89 percent to 7.30 lira after Sabanci said late on Wednesday it had signed a deal with Spain's International Paper Container Holdings for the sale of its 43.73 percent stake in the company.
By 0739 GMT, the lira was at 1.8015 against the dollar , slightly weaker than 1.7955 late on Wednesday. Against its euro-dollar basket, it stood flat at 2.0689.