Can LHRH Injections, Superior Cervical Ganglionectomy and Pinealectomy Re-Initiate Estrous Cycles in Old Prolonged Vaginal Cornification female rats?

The effects of LHRH injections, superior cervical ganglionectomy and pinealectomy on re-initiation of estrous cycles in old prolonged vaginal cornification female rats (19 to 30 months of age) were studied. Eight among 14 PVC rats which received single or daily injection of LHRL-I 1 μg/100g/day for 7 days, reinitiated 2 to 7 cycles and all of 14 rats had corpora lutea formation in their ovaries. Superior cervical ganglionectomy could not reinitiate estrous cycles in 7 old PVC rats and in 8 androgen sterilized female rats. After pinealectomy 2 out of 5 old PVC rats and 2 out of 13 androgen sterilized rats reinitiated 1 to 2 estrous cycles and fresh and medium size old corpora lutea were found in 1 and 2 old PVC rats respectively. In the control group of sham pinealectomized old PVC rats, 2 out of 4 rats reinitiated 2 to 3 cycles and 1 rat had corpora lutea formation. These results indicate that old PVC rats have deficient LHRH release mechanism(s) and that the pineal gland has nothing to do with the maintenance of PVC smear in old female rats.