[Estradiol, progesterone and cyclic nucleotides in the fluid of persistent follicles and luteal phase follicles in the estrus cycle in cows]

Abstract

The objective of the present study was to compare the concentrations of 17 beta-estradiol, progesterone, cyclic adenosine monophosphate and cyclic quinosine monophosphate in the largest follicles of cows that persist for seven days after insemination following the preceding synchronization of oestrus and superovulation and in follicles of the luteal phase of cycle (5th-10th days). Animals included in the experiment were selected on the basis of rectal examination. Synchronization of oestrus was achieved in 24 crossbreds of Slovak Pied x Lowland Black Pied breeds (SS x Nc) using two doses of cloprostenol of Czechoslovak provenience Oestrophan Spofa, 500 micrograms in each, within 11 days. Serum gonadotrophin at the amount of 2500 I. U. was administered forty-eight hours before administration of the second dose PGF2 alpha. Experimental animals were inseminated after 72 hours. On the 7th day after mating the cows were killed at a slaughterhouse. Evaluated were only the ovaries of the 14 cows in which the persistent large follicles occurred. Ovaries of the 13 control cows in the luteal phase between the 5th-10th days were obtained at the slaughterhouse by the method after Ireland et al. (1980). Correct determination of the phase of sexual cycle was substantiated by determination of progesterone concentrations in blood serum. Follicular fluid was obtained from the largest follicles by aspiration and centrifuged in a cooled centrifuge at 3000 G. The concentrations of 17 beta-estradiol and progesterone in follicular fluid were determined using kits from URVJT at Kosice, designated RIA-test-ESTRA (SI-125-9) or RIA-test-Prog (SI-125-6).2+ persistent follicles (9.15 +/- 5.47 nmol.l-1).(ABSTRACT TRUNCATED AT 250 WORDS)