Search results for "Folliculogenesis"
showing 6 items of 6 documents
Monitoring the reproductive activity in captive bred female ball pythons (P. regius) by ultrasound evaluation and noninvasive analysis of faecal repr…
2018
The royal python (Python regius) is commonly bred in captivity. To have a successful breeding season, accurate monitoring of the reproductive activity is necessary. The use of non-invasive monitoring methods in exotics is important in order to minimize stress. For this purpose ultrasound has been anecdotally used to monitor royal python reproductive activity. However, there is limited information regarding the reproductive cycle of this species. The aim of the present study is to monitor the female reproductive cycle of the royal python using ultrasonography and gonadal steroid metabolite measurements in the faeces. The reproductive activity of one hundred twenty-nine adult female P. regius…
Hormonal and molecular characterization of follicular fluid, cumulus cells and oocytes from pre-ovulatory follicles in stimulated and unstimulated cy…
2012
background: The use of ovarian stimulation, to stimulate a multi-follicular response for assisted reproduction treatments, may force the production of oocytes from follicles that do not reach optimal maturation, possibly yielding oocytes that are not fully competent. The present study aimed to define the follicular environment and oocyte competence of unstimulated pre-ovulatory follicles, to compare it with that of similar-sized stimulated follicles. For this purpose, we analyzed the follicular hormonal milieu, the oocyte meiotic spindle, the embryo development and the cumulus cells gene expression (GE) profiles. methods and results: The study population was divided in two groups: (i) 42 oo…
Intraovarian regulation of gonadotropin-dependent folliculogenesis depends on notch receptor signaling pathways not involving Delta-like ligand 4 (Dl…
2013
Background In-situ hybridisation studies demonstrate that Notch receptors and ligands are expressed in granulosa cells (GCs) and in the theca layer vasculature of growing follicles. Notch signaling involves cell-to-cell interaction mediated by transmembrane receptors and ligands. This signaling pathway may represent a novel intraovarian regulator of gonadotropin-dependent follicular development to the preovulatory stage. We hypothesized that blocking Notch pathways would disrupt follicular maturation in the mouse ovary. Methods Hypophysectomized CD21 female mice were administered pregnant mare serum gonadotropin (PMSG) for 3 days to stimulate follicular development. In one experiment, a pan…
A comparison of the effects of bilateral efferent duct ligation and of partial epididymectomy on the testes of rats.
1990
Testis weight as a percentage of body weight did not change following bilateral ligation of the efferent ducts (EDL) close to the epididymis, whereas following removal of part of the epididymis between the site of ligation and a point close to the junction between the caput and corpus (PCE), testis weight first rose linearly until Day 4 and then showed an exponential decrease between Days 4 and 28. After EDL, the perimeter of the seminiferous tubules rose for the first 7 days and then remained elevated, whereas after PCE, there was a linear decrease between Days 4 and 28. Following EDL, the percentage of altered and degenerated tubular cross-sections rose to about 30% and 10%, respectively,…
65 ASSOCIATION BETWEEN ALDOSTERONE AND CORTISOL LEVELS DURING THE OVULATORY PERIOD IN SPANISH PUREBRED MARES
2014
Preovulatory increased aldosterone (ALD) has been described as one of the physiological events that characterise the oestrous cycle in relation to the dynamics of the renin angiotensin aldosterone system. Within the mechanisms associated with this response are the stimulating effect of oestrogen on the synthesis of angiotensinogen, haemodynamic variations of renal blood flow, changes in sodium concentration, changes in the local sympathetic activity, and the effect of cortisol (CORT). In fact, CORT via adrenocorticotropic hormone contributes primarily to preovulatory ALD, and it is the primary regulator factor synthesis ALD (Chidambaram et al. 2002; Pechère-Bertschi et al. 2002; Szmuilowic…
66 RELATIONSHIP BETWEEN PLASMA CHLORIDE LEVELS AND FOLLICLE DIAMETER IN CYCLING SPANISH PUREBRED MARES
2014
Several studies in cows have shown that plasma levels of chloride are positively correlated with the diameter of the preovulatory follicle (FD), establishing at the same time a significant positive association between plasma levels and intraoviducal concentration of this electrolyte (Hugentobler et al. 2007). These relationships may reflect the influence of changes in systemic metabolic plasma on follicular fluid, physiological events that might be closely related to the quality of the oocyte and granulosa cells of the preovulatory follicle (LeRoy et al. 2004). However, these mechanisms remain unknown in the mare. The objective of this research was to investigate the relationship between p…