The objective of the present study was to characterize changes in growth, concentrations of steroids in follicular fluid (FF) and gonadot ropin receptors of individual antral follicles after spontaneous luteolysis in heifers and to reexamine our hormonal method of classifying healthy and atretic follicles. Groups of heifers were ovariectomized (OVX) before regression of corpora lutea on d 17, 1...

Correction After publication of the original article [1] it was noted that the caption of Table two was incorrect. This caption should read “Distribution of ovarian follicles depending on the type (healthy, transitional, and atretic). Small superscript letters a and b indicate significant differences in the respective ovarian follicle numbers within the various types of follicles (P < 0.05) as ...

Effects of daidzein on expression of mRNAs of gonadotropin receptors (FSHR, LHR) and P450 aromatase (P450arom) were evaluated in ovarian follicles of white silky fowls. The hens were 13 months old in the post-peak period of egg laying and were randomly allocated as control and daidzein-treated groups, with daidzein supplemented to the basal diet at 10 mg/kg for 7 consecutive weeks. The mRNA exp...

The theca interna is a specialized stromal layer that envelops each growing ovarian follicle. It contains capillaries, fibroblasts, immune cells and the steroidogenic cells that synthesize androgens for conversion to estradiol by the neighboring granulosa cells. During reproductive life only a small number of follicles will grow to a sufficient size to ovulate, whereas the majority of follicles...

BACKGROUND There is substantial evidence both in humans and in animals that a prolonged reduction in plasma thyroid hormone concentration leads to reproductive problems, including disturbed folliculogenesis, impaired ovulation and fertilization rates, miscarriage and pregnancy complications. The objective of the present study is to examine the consequences of chronic hypothyroidism, induced in ...

Angiotensin II (AngII) is best known for its role in blood pressure regulation, but it also has documented actions in the reproductive system. There are two AngII receptors, type 1 (AGTR1) and type 2 (AGTR2). AGTR2 mediates the noncardiovascular effects of AngII and is expressed in the granulosa cell layer in rodents and is associated with follicle atresia. In contrast, expression of AGTR2 is r...

The aim of the present study was to investigate the effects of activin-A and follistatin on in vitro primordial and primary follicle development in goats. To study primordial follicle development (experiment 1), pieces of ovarian cortex were cultured in vitro for 5 days in minimal essential medium (MEM) supplemented with activin-A (0, 10 or 100 ng/ml), follistatin (0, 10 or 100 ng/ml) or combin...

BACKGROUND Zucker fatty (fa/fa) rats are a well-understood model of obesity and hyperinsulinemia. It is now thought that obesity/hyperinsulinemia is an important cause of endocrinological abnormality, but to date there have been no reports on the changes in ovarian morphology or the ovarian androgen profile in rat models of obesity and insulin resistance. METHODS In this study we investigated...

BACKGROUND The physiological state of the dominant follicle is important as it may be linked to the competence of the oocyte within. The objective of this study was to analyze, by transcriptomic analysis, the changes occurring in granulosa cells from dominant follicles at different phases of follicular growth. METHODS Granulosa cells were collected from slaughterhouse dairy cattle follicles w...

Regulation of ovarian activity is an integrated process encompassing both extraovarian signals and intrafollicular factors. Initiation of primordial follicle growth and the early stages of folliculogenesis can occur without gonadotropins, but FSH may affect the rate of preantral follicle growth. Antral follicle development from 1 to 4 mm in sheep and cattle is completely gonadotropin dependent....