Comparison of hormonal and histological changes during follicular growth, as measured by ultrasonography, in cattle

Abstract

The aim of the study was to compare histological and endocrinological indices of ovarian follicle health in cattle with monitoring of follicle growth and regression by ultrasound imaging in vivo. Ultrasound scanning was performed daily. Follicles were obtained at ovariectomy; follicular fluid was collected for assay, and the degree of atresia was assessed histologically. Histological atresia was correlated with growth patterns when anovulatory growing and regressing follicles were compared (P < 0.05), but was not different between growing and static follicles. Oestradiol concentrations were lower in static than in growing follicles, although the difference was not significant (35 +/- 7 versus 260 +/- 120 ng ml-1; P < 0.08), and were significantly lower in regressing follicles (7 +/- 5 ng ml-1; P < 0.05). Oestradiol concentrations were significantly lower in histologically atretic than in nonatretic follicles (16 +/- 8 versus 282 +/- 132 ng ml-1; P < 0.05), but were not different between nonatretic and early atretic follicles (P > 0.05). There was a significant negative correlation between oestradiol concentration and the number of days the follicle was visible by ultrasound (r = -0.71; P < 0.001). Concentrations of progesterone in follicular fluid were correlated with the number of days the follicles were detected (r = 0.61; P < 0.01) and were higher in regressing than in growing follicles (122 +/- 71 versus 48 +/- 13 ng ml-1; P < 0.05) but not significantly higher in atretic compared with nonatretic follicles (129 +/- 102 versus 53 +/- 15 ng ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Control of oestradiol secretion and of cytochrome P450 aromatase messenger ribonucleic acid accumulation by FSH involves different intracellular pathways in oestrogenic bovine granulosa cells in vitro

“…Oestradiol was measured in conditioned medium without extraction (Price et al 1995). Inter-and intra-assay coefficients of variation were 12 and 10% respectively.…”

Expression of protease nexin-1 and plasminogen activators during follicular growth and the periovulatory period in cattle

“…100 ng progesterone/ml were classified as atretic (n ¼ 4). These represent mature dominant growing, static and regressing follicles respectively (Price et al 1995). Cross-contamination of theca and granulosa cells was tested by detection of mRNA encoding cytochromes P450 aromatase (Cyp19) and 17a-hydroxylase (Cyp17) in each sample by PCR (Buratini et al 2005).…”

“…Concentrations of estradiol and progesterone in FF from Experiment 3 were analyzed by RIA using double antibody precipitation and charcoal absorption methods, as validated for use with bovine FF (Carrière & Lee 1994, Price et al 1995. Spiking FF samples with 2 pg/tube and 5 pg/tube of estradiol gave 81 and 107% recovery respectively.…”

Measurement of redox potential and steroid concentrations in the follicular fluid of growing and regressing follicles of mares

“…Nonatretic follicles contain higher oestradiol and lower progesterone concentrations than do atretic follicles (Ireland and Roche, 1983;Richards and Kirdich, 1984;Blödow et al, 1988). Other studies indicate that static follicles, containing lower oestradiol concentrations, may not all be truly atretic (Price et al, 1995). It was also shown that histological results did not correlate well with the stage of follicular growth or regression as determined either in vivo by ultrasound scanning of ovaries or by assessment of follicular concentrations of oestradiol, progesterone or inhibin.…”

“…In addition, morphologically and clinically healthy follicles are characterised by several visible indices (Moor et al, 1978;McNatty et al, 1984;Fortune, 1994). Histological studies have defined Acta Veterinaria Hungarica 54, 2006 several degrees of atresia based on pyknotic nuclei, thickness of granulosa cell layers and membrane integrity (Price et al, 1995;Blondin et al, 1996;Zeuner et al, 2003). Determination of hormonal concentrations in the follicular fluid is also used to indicate the health status of follicles.…”