Fine Structures of the Oocyte in Relation to Serum, Follicular Fluid Steroid Hormones and IGF-I in the Ovulatory-Sized Follicles in One-Humped Camel (Camelus dromedarius).

BACKGROUND: The following study was carried out to determine the ultrastructural features of the oocyte of the ovulatory-sized follicles in relation to concentrations of steroids and IGF-I in the Follicular Fluid (FF) and serum in the dromedary camel. METHODS: CAMEL FOLLICLES WITH A CLEAR AND HEALTHY APPEARANCE WERE CATEGORIZED INTO THREE CLASSES: follicles 10 to 13.9, 14-17.9 and 18-30 mm diameter. The FF and serum samples were assayed for estradiol-17ß, progesterone and IGF-I. Recovered Cumulus-Oocyte Complexes (COCs) were prepared for transmission electron microscopy. RESULTS: The mean (±SD) FF concentrations of progesterone and IGF-I was significantly (p < 0.05) higher in follicles 18 to 30 mm diameter compared to other groups of follicles. There was no difference in the mean (±SD) serum estradiol-17ß, progesterone and IGF-I concentrations between camels with different ovulatory-sized follicles (p > 0.05). Oocytes from follicles 18 to 30 mm diameter (group 3) showed more advanced signs of maturation including the disappearance of the nuclear envelope, increased number of microvilli in erect position, the increase in number and size of vesicles and more even distribution of the mitochondria throughout the ooplasm. CONCLUSION: The final stages of oocyte maturation in dromedary camel is associated with increasing progesterone and IGF-I concentrations and constant high estradiol concentration in the follicular fluid which are paralleled with well-defined ultrastructural changes in oocytes.

Stereological study of the effects of letrozole and estradiol valerate treatment on the ovary of rats.

OBJECTIVE: Letrozole and estradiol valerate are used to treat some hormonally-responsive symptoms and also in modeling of the polycystic ovary syndrome. However, the stereological analysis of the ovary has received less attention. Estimation of the whole ovary volume using the Cavalieri method can be applied in any orientation desired, but estimation of the mean volume of the oocytes requires isotropic uniform random sectioning. Here, a combined method was developed for estimating the parameters. To our knowledge, no comparison has been made of the effects of letrozole and estradiol on the ovary. METHODS: Sixty rats were divided into 4 groups receiving estradiol (4 mg/kg), olive oil, letrozole (1 mg/kg), or normal saline. After 21 days, their ovaries were studied. RESULTS: Relative to the control group, the total volume of the ovary and the cortex increased in the letrozole-treated and estradiol-treated rats. In addition, the number of the preantral, antral, and granulosa cells decreased by 43% to 56% in the letrozole- and estradiol-treated rats. On average, a 19% increase was observed in the atretic oocytes of the letrozole-treated and estradiol-treated rats, but the mean oocyte volume decreased by 29% to 44% in letrozole- and estradiol-treated rats. Furthermore, the letrozole-treated rats showed a 5-fold and 7-fold increase in the volume of the cysts and corpus luteum, respectively. A 3-fold increase was found in the volume of both the cysts and corpus luteum in the estradiol group. CONCLUSION: The structural changes of the ovary were most pronounced in the letrozole-treated animals.