adhesion were not significantly reduced by the loss of PI3K␥. Teflon-coated 12-well glass slides (Marienfeld) were coated with fibronectin (20 g/ml; Sigma) solution. Calcein-AM (Molecular Probes)-loaded PMNs (20 l) were applied to the glass slides. After stimulation, nonadherent cells were removed by washing. Fluorescence of attached cells was measured in a Bio-Tek FL600 fluorescence plate reader (excitation, 485 nm, 20-nm slit; emission, 530 nm, 25-nm slit). 12. M. Romano et al., Immunity 6, 315 (1997). 13. C. Nathan et al., J. Cell. Biol. 109, 1341(1989 DARPP-32, a dopamine-and adenosine 3Ј,5Ј-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D 1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.Progesterone (P) and dopamine (DA) facilitation of sexual receptivity in female rats requires intact, intracellular progestin receptors (PRs) (1). Wild-type female mice exhibit high levels of P-and DA-facilitated lordosis, whereas homozygous females carrying a null mutation for the PR gene show minimal reproductive behavior (2, 3). These observations substantiate a critical role for the PR as a transcriptional mediator for the signal transduction pathways initiated by P and DA. DA, signaling through the D 1 subclass of receptors in the neostriatum, induces increases in the levels of adenosine 3Ј,5Ј-monophosphate (cAMP) and activates cAMP-dependent protein kinase (PKA) (4). Dopamineand cAMP-regulated phosphoprotein-32 (DARPP-32) is phosphorylated by PKA. In its phosphorylated state, this molecule, by inhibiting the activity of protein phosphatase-1 (PP-1), increases the state of phosphorylation of many substrate proteins, leading to the induction of physiological responses (4). To determine whether DARPP-32 might be involved in P and DA actions on the hypothalamus, we examined its role in the facilitation of sexual receptivity in female rats and mice (5).Antisense oligonucleotides to the PR inhibit P-facilitated lordosis in female rats (6, 7). We used a similar strategy to examine the role of DARPP-32 in P-and DA-facilitated sexual receptivity. Ovariectomized, estradiol benzoate (EB)-primed, Sprague-Dawley female rats with stereotaxically implanted stainless steel cannulae in the third cerebral ventricle (5) exhibited high levels of P-facilitated lordosis in the presence of males (Fig...

Housing adult rats on ground corncob bedding impedes male and female mating behavior and causes acyclicity in females. The suppressive effects on ovarian cyclicity are mimicked by a mitogenic agent purified from the ground corncob bedding material (corn mitogen; CM), which stimulates the proliferation of estrogen receptor (ER)-positive (MCF-7 cells) and ER-negative (MDA-MD-231 cells) breast cancer cells. Purified CM does not compete for [(3)H]estradiol binding to ER or nuclear type II sites, and its effects on MCF-7 breast cancer cell proliferation are not blocked by the antiestrogen ICI-182,780. These results suggest that the active component is unlikely to be a phytoestrogen, bioflavonoid, mycotoxin, or other known endocrine-disrupting agent that modifies cell growth via ER or type II [(3)H]estradiol binding sites. CM also stimulates the proliferation of PC-3 human prostatic cancer cells in vitro, and the growth rate of PC-3 cell xenografts is accelerated in nude male mice housed on ground corncob as opposed to pure cellulose bedding. Consequently, this endocrine-disrupting agent in ground corncob bedding may influence behavioral and physiologic reproductive response profiles and malignant cell proliferation in experimental animals. Fresh corn (kernels and cob) or corn tortillas also contain CM, indicating that human exposure is likely; consequently, CM and/or related mitogens in corn products may influence human health and development.

T2*-CMR accurately quantified myocardial reperfusion hemorrhage in vivo. Hemorrhage was associated with more severe infarct-related injury.