Changes in plasma kininogen levels in rats before ovulation, and after treatment with luteinizing hormone and oestradiol-17 beta.
The pre-ovulatory fall in plasma kininogens in rats with 4 day oestrous cycles started between 12.00 and 15.00 h pro-oestrus, reached a maximum decline of 51% by 18.00 h pro-oestrus, and started to recover before ovulation. Because these changes appeared to correspond with the LH-surge, and to follow the peak in plasma oestradiol-17 beta levels, both of these hormones were tested for possible effects on plasma kininogens. Intracardiac injections of 110 IU of equine LH into dioestrous rats were followed by a decline of 30.8 +/- 6.7% in plasma kininogens, 6 h after injection (significant, P less than 0.01). Values were still depressed, but recovering, 12 h after treatment; the reduction was 21.3 +/- 5.8% (significant, P less than 0.01). Controls showed no decline. Injections of oestradiol-17 beta (1.0 micrograms/100 g body weight) produced no significant effects. It is suggested that the LH surge may be responsible, at least in part, for the decline in plasma kininogens seen before ovulation.
D000818:Animals; D001920:Bradykinin / Q000097:blood*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007986:Luteinizing Hormone / Q000494:pharmacology*; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy; D011359:Proestrus / Q000187:drug effects; D011498:Protein Precursors / Q000097:blood*; D051381:Rats
D011498:Protein Precursors; C009858:bradykininogen; D004958:Estradiol; D007986:Luteinizing Hormone; D001920:Bradykinin