With maintained low levels of progesterone and higher levels of an estrogenic mimetic, we hypothesized that the dramatic threshold and subsequent withdrawal in progesterone needed for normal hypothalamic gonadal signaling does not occur; therefore, the mice remained in metestrus
and ceased to cycle.
Cytological features following vaginal smear represent each stage of estrous cycle Stage of Nucleated Squamous Cornified squamous estrous cycle epithelial cells epithelial cells epithelial cells Proestrus + - - Estrus - + - Metestrus
- - + Diestrus - - - Stage of Leukocytes estrous cycle Proestrus - Estrus - Metestrus
+ Diestrus + Proestrus, predominantly consisting of nucleated epithelial cells; estrus, with cornfield squamous epithelial cells; metestrus
, consisting of cornified squamous epithelial cells and predominance of leukocytes; and diestrus, consisting predominantly of leucocytes Table 2.
In captivity, the estrous phase lasted up to five days, followed by metestrus
of up to 2 days.
At the high dose, the study recorded a reduction in the metestrus
, proestrus (p < 0.05) and estrus phases, and an increase in the diestrus phase compared to the control (Table 2).
Analysis of Variance (ANOVA) revealed no significant differences in paw withdrawal latencies between female that received saline and drug (5 min and 30 min) in the different estrous cycle phases (figure not shown); estrus: (F (3, 22)= 0.128, p= 0.94, n.s.), metestrus
(F (3, 24)= 1.146, p= 0.35, n.s.), proestrus (F (3,24)= 1.174, p= n.s.) and diestrus (F (3,26)= 3.045, p= n.s.).
The 17[beta]-estradiol concentrations of one female, proestrus 77.26 [+ or -] 20.71pg/ml (62.6291.91pg/ml), estrus 82.24 [+ or -] 10.96pg/ml (74.4990pg/ml), metestrus
75.88pg/ml, diestrus 85.74 [+ or -] 13.59pg/ml (71.93-109.37pg/ml), were low when compared to the samples mentioned above (Fig.
Because ovulation was lesser in cows receiving the GnRH on day 3 than day 6, a new follicular wave was observed in fewer cows when the first injection of GnRH was administered during metestrus
than diestrus, thereby extending the period of follicle dominance during the Ovsynch protocol.
The estrous cycle is traditionally divided into four phases: proestrus, estrus, metestrus
, and diestrus (Figure 10-2).
Recent experiments in our laboratory have demonstrated that TGasel is expressed in vaginal epithelium of mature mice during the stages of the estrous cycle when estrogen levels are high, namely, estrus, metestrus
, and diestrus.
(meht-ehs-truhs) A period following estrus that is characterized by the development of the corpus luteum and production of progesterone.
Progesterone concentrations differed significantly (p<0.05) during metestrus
(d 2 to d 7) but not during diestrus (d 7 to d 12).
The aim of the present work was to provide the literature with helpful considerations regarding the distribution of cornified cell determinations during proestrus, estrus, metestrus
and diestrus in rats receiving estrogen.