[Steroid dominance, enzyme activity and morphological appearance of granulosa cells in the largest follicles in cows].

: The cyclic nature of the female reproduction process depends to a considerable degree on the unique capacity of ovarial follicles to change their structure and function. The differentiation process during folliculogenesis takes place in all parts of the follicle. Granulosa cells reflect a high degree of structural changes and play an important role in functional maturation of the inert follicle. Changes in the reaction to endocrine and paracrine effects from a unique environment that is inevitably necessary for oocyte growth and ovulation were reached by changes in the biochemical activity and the internal anatomic mutual relation of the follicle (Linder et al., 1976; Hsueh, 1976). This growth process and differentiation depend on gonadotropic stimulation of the follicles and the quantity of receptor sites able to bind them. The aim of this work was compare estradiol 17-beta and progesterone levels in the follicular fluid of the largest follicles with the morphological structure and enzymatic activity of membrana granulosa cells. Ovaries were obtained from 34 SS x LBS randomly chosen cows at the slaughter-house. Follicular fluid to estradiol 17-beta and progesterone level determination was obtained by aspiration of the largest follicles. Estradiol 17-beta and progesterone levels were determined by RIA sets from the URVJT (Institute of Radioecology and Use of Nuclear Techniques) in Kosice, type RIA-test-ESTRA (SI-125-129) and RIAA-test-Prog (SI-125-6), respectively. With the methods used the variation coefficient of intra- and interassay for the estradiol 17-beta of the RIA set were 10.1 and 13.3%, for progesterone of the RIA set these values were 11.4 and 13.7% respectively. Steroid dominance of follicles was determined by the method described by Căllesen et al. (1986), based on the expression of the index of the mutual relation between progesterone levels and estradiol 17-beta was levels. Excisions from the follicular wall were examined under the scanning electron microscope JEOC 1200 Mx at an acceleration voltage of 20 kV. In granulosa cell smears acid phosphatase and non-specific esterase activity were determined by incubation in the incubation media according to Lojda et al. (1979). Steroid levels are given in nmol/l +/- SEM. Mean estradiol 17-beta levels in estrogen dominant follicles were proved to be 2170.0 +/- 1605.3 nmol/l, whereby individual concentrations ranged from 17.0 nmol/l to 10180.0 nmol/l.(ABSTRACT TRUNCATED AT 400 WORDS)