Blind, olfactory bulbectomized female rats do not have daily luteinizing hormone surges

Previous studies from other laboratories have shown that female hamsters on short photoperiod become acyclic and have daily LH surges. These effects are eliminated if the animals are pinealectomized (PX) before being placed on the short photoperiod. Reiter and colleagues have shown that pre-pubertally blinded (BL) and olfactory bulbectomized (BX) female rats also have irregular estrous cycles, and this effect is also eliminated by PX [Endocr. Rev., 1 (1983) 109]. The main question addressed by the present study was whether the BL + BX rats also have daily LH surges. Twenty-five-day-old female Sprague-Dawley rats were divided into 5 groups: LD 14:10 sham (control); BL + BX; BL + BX + PX; LD 6:18 sham; and LD 6:18 BX. Ten weeks following surgery, all animals were sampled (0.5 ml) every 5 h for 2 days from an indwelling atrial catheter. Daily vaginal smears indicated that the BL + BX group were in estrus much less frequently than controls (15.8 +/- 1.8 vs 27.3 +/- 1.5% of days cornified cells, 10 rats/group smeared for more than 23 days each) and in general had longer, irregular cycles. The other 3 groups all had smear patterns similar to controls. All 5 groups had LH surges on the day of proestrus (greater than 200 ng/ml maximum value), but no group had LH surges on 2 sequential days or an LH surge on any other day of the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)