Lactoferrin expression in the mouse reproductive tract during the natural estrous cycle: correlation with circulating estradiol and progesterone.

Abstract

Lactoferrin (LTF), an iron-binding glycoprotein present in most exocrine secretions and in the secondary granules of polymorphonuclear leucocytes (PMN), is regulated by estrogen in the mouse reproductive tract. We investigated the expression of LTF mRNA and protein during the natural estrous cycle to increase our understanding of how this uterine secretory protein is regulated under physiological conditions. There was a positive correlation between LTF mRNA expression in the genital tract and serum estradiol (E2) concentrations. When E2 peaked in proestrus, LTF mRNA and protein were expressed in the uterus; however, during metestrus, when both E2 and progesterone levels were high, LTF mRNA was expressed, while LTF protein was decreasing. LTF protein expression may be hindered by progesterone or some other local factor in the endometrial epithelium after ovulation. Immunohistochemistry demonstrated two distinct staining patterns for LTF in the vaginal and endometrial epithelium. In one staining pattern, the colorimetric reaction was noted over the cytoplasm, and in the other, the nuclear region stained more intensely. This suggests the possibility that in addition to its known role as a secretory protein, LTF may be transported to the nucleus, serving an autocrine role. Our results also indicated that LTF protein is a useful marker for tracking PMN. Nonproliferating epithelial cells in the vagina and endometrium may synthesize chemotactic and/or adhesion molecules for PMN.

Differential Effects of Estrogen Receptor Alpha and Beta Specific Agonists on Social Learning of Food Preferences in Female Mice

“…The shorter preference for the demonstrated food shown by the ovariectomized (ovx) oil and 30 and 180 mg/kg WAY-200070 groups closely resemble that of estrus females (Clipperton et al, 2006), who have low levels of estrogens (Walmer et al, 1992). WAY-200070 at 90 mg/kg prolonged the maintenance of the socially acquired food preference by these ovx mice to a level akin to that shown by intact females in proestrus and diestrus (Clipperton et al, 2006), when estrogen levels are higher and progesterone levels are low (Walmer et al, 1992).…”

“…WAY-200070 at 90 mg/kg prolonged the maintenance of the socially acquired food preference by these ovx mice to a level akin to that shown by intact females in proestrus and diestrus (Clipperton et al, 2006), when estrogen levels are higher and progesterone levels are low (Walmer et al, 1992). This, in conjunction with the present results, suggests that the longer-maintained preference for the demonstrated food seen in proestrus and diestrus females may be a result of the action of estrogens on ERb countering those on ERa, either directly or through effects on subordination.…”

“…Additionally, we have recently shown that, when tested immediately, the preference for the demonstrated food lasted 1.5-2.5 times longer in diestrus and proestrus females than in estrus and ovariectomized mice (Choleris et al, in preparation). As estrogens are low in ovariectomized mice and intact females in estrus, and higher in proestrus and diestrus females (Walmer et al, 1992), they may be involved in the STFP.…”

Gene array profiling of large hypothalamic CNS regions in lactating and randomly cycling virgin mice

“…Our finding of elevated variance in the L versus V group when examining the top 100 genes showing differences in expression between groups (data not shown; see Supplemental Table 1 for raw results) is evidence of this kind of noise; while it may indicate that certain, subtler differences between the groups' gene expression were missed by the array, it also strengthens our confidence in those results that were significant. V mice were either in estrus, diestrus I, diestrus II (periods of relatively consistent estradiol and progesterone levels) [10], or the morning of proestrus, so levels of estradiol and progesterone both could have ranged between 10 and 60 ng/ml [50]. These steroid ranges coincide with those found during pregnancy [27], but are higher than the low levels observed around postpartum Day 7 in mice [45].…”

Progesterone signalling in breast cancer: a neglected hormone coming into the limelight

“…Cell proliferation is observed during the luteal phase when high serum progesterone levels prevail. In fact, hormonal secretion follows a similar pattern in the two species, with a progesterone peak after ovulation 44 . However, the oestrous cycles of mice are not regular and are poorly delineated 45 .…”