Male stimulation of luteinizing hormone surge, @entity1420 secretion and ovulation in spontaneously persistent-estrous, aging XXXX .

@entity35 @entity1515 @entity400 @entity1420
In aging, @entity400 ( @entity400 ) female @entity35 , there are no estrous cycles or cyclic increases in luteinizing hormone (LH) secretion, but the sexual receptivity to the male is consistently maintained. We recently reported that caging and mating with fertile males elicits an LH surge followed by ovulation in aging @entity400 @entity35 . The present study examined the relationship between the LH surge, the increase in @entity1420 (P) secretion and ovulation in @entity400 females exposed to males, and assessed whether intromission was essential for the male-induced pre-ovulatory LH surge. @entity400 @entity35 were implanted with intra-atrial cannulae. Six to eight days later, these females were individually caged with a fertile male and repeatedly sampled (once every 30 or 60 min) between 1400 and 1900 h for assays of plasma LH and P. Sexual behavior of the female was recorded and correlated with the changes in plasma LH and P values. Similar experiments were also performed on cannulated @entity400 @entity35 with their vaginal orifice blocked with adhesive tape during the caging and sampling session. In both experiments, over 90% of the @entity400 females displayed a high degree of @entity1515 response to mounting by the male, and over 60% of those sexually receptive @entity400 females exhibited an LH surge followed by ovulation. The male-induced preovulatory LH surge occurred in @entity400 females without actual intromission. Caging with fertile males also elicited a marked increase in plasma P concentrations in @entity400 @entity35 and in @entity400 females prevented from experiencing intromission.(ABSTRACT TRUNCATED AT 250 WORDS)
