the transcriptional factor oct4 regulates pluripotency of stem cells and has an important role during oocyte growth. whereas, its role has remained ambiguous in ovarian tissue during reproductive cycle. therefore, this study was aimed to investigate the expression patterns of oct4 in mouse ovaries during the normal estrous cycle. adult national medical research institute mice were classified as...

The study aimed at obtaining basic information about estrous cycle in rats treated with dexamethasone, for polycystic ovaries, induced by constant illumination. It was used 30 female rats (Rattus norvegicus albinus) from the lineage Wistar, with 90 days years old, divided according the following groups: Group I rats maintained in a light/dark cycle for 12/12 hours, and after 100 days submitted ...

The preovulatory luteinizing hormone (LH) surge results from the integration of complex interactions among gonadal steroids and hypothalamic and pituitary hormones. To evaluate changes in LH secretory dynamics that occur during the rat LH surge, we have 1) obtained frequently sampled serum LH concentration time series, 2) used both waveform-dependent and waveform-independent convolution analyse...

Neurons responsive to stimulation of the temporomandibular joint (TMJ) region were recorded from superficial laminae at the trigeminal subnucleus caudalis/upper cervical cord (Vc/C(2)) junction region of cycling female rats under barbiturate anesthesia. To determine if receptive field (RF) properties or sensitivity to algesic chemicals of TMJ units vary over the estrous cycle, animals were sele...

The mossy fiber (MF) pathway is critical to hippocampal function and influenced by gonadal hormones. Physiological data are limited, so we asked whether basal transmission and long-term potentiation (LTP) differed in slices of adult male and female rats. The results showed small sex differences in basal transmission but striking sex differences in opioid receptor sensitivity and LTP. When slice...

Neuropeptide Y (NPY) has been shown to potentiate the actions of LHRH during the generation of preovulatory LH surges. It is not yet known, however, if activation of a specific subtype of NPY receptors in the anterior pituitary gland is an obligatory event in the stimulation of spontaneous LH surges. A battery of NPY receptor agonists, as well as the specific NPY Y1 receptor antagonist BIBP3226...

We have reported that splenic macrophages play a role in the regulation of progestin secretion in rats. In this study, splenic macrophages were obtained from cycling rats at different estrous cycle stages and co-cultured with luteal cells from mid-pseudopregnant rats in the absence/presence of prolactin (PRL) or luteinizing hormone (LH). The effect of macrophages on the luteotropic action of PR...

BACKGROUND Previous work by our lab and others has implicated glutamate as a major excitatory signal to gonadotropin hormone releasing hormone (GnRH) neurons, with gamma amino butyric acid (GABA) serving as a potential major inhibitory signal. However, it is unknown whether GABAergic and/or glutamatergic synaptic appositions to GnRH neurons changes on the day of the proestrous LH surge or is af...

The effects of prolonged infusions of prolactin (PRL) into the third ventricle of the brain of cycling ewes on the secretory activity of hypothalamic GnRH neurons and pituitary LH cells in the pars distalis during the proestrous day were studied. Mature Blackhead ewes were infused with vehicle (control, n=5) or with prolactin (200 mug/day, n=5) during 4 consecutive days prior to the next sponta...