bFGF is among a family of growth factors whose members are involved in everything from the formation of new blood vessels and wound healing to embryonic development and various endocrine signaling
Of particular concern is the proposal that EDCs must have a single known "mode of action," which "represents a fundamental misunderstanding of how endocrine signaling works by connecting different organ systems within the body," said Dr.
Ultimately, enacting such tight criteria would tie the hands of regulators with regard to newly recognized and even some well-studied EDCs, "despite evidence that they affect endocrine signaling, because their mode of action is not yet known," Dr.
Moreover, functional interactions between these two nuclear receptors may influence endocrine signaling
participating in the progression of breast and prostate cancers.
They may communicate directly through juxtacrine signaling, over short distances through paracrine signaling and over large distances through endocrine signaling
. Additionally, some cells require cell-to-cell contact in order for communication to occur.
Brain anatomy, endocrine signaling
, and socialization are considered and addressed.
To effectively evaluate a chemical's potential for endocrine disruption, a testing protocol must be able to measure hormone-like effects or perturbations at very low chemical doses, as well as to take into account the many possible ways the chemical may interact with endocrine signaling
Although all obesogen chemicals are not yet identified, and their detailed mechanisms of action remain to be explored, generally it is assumed that exposure to different doses of these environmental chemicals in various periods of life from fetal to adult period interacts with some endocrine signaling
mechanisms and in turn leads to obesity.
Of particular relevance to the EDSP, roughly 15% of the ToxCast assays examine various aspects of the estrogen (six assays), androgen (five assays), and thyroid (five assays) signaling pathways, as well as a number of other nuclear receptor (NR) pathways (e.g., glucocorticoid receptor, peroxisome proliferator--activated receptor, pregnane X receptor; 36 assays) and xenobiotic-metabolizing enzymes (XMEs; cytochrome P450s, including aromatase; 38 assays) that have potential relevance to endocrine signaling
. Because phase I of ToxCast capitalized on the richness of traditional toxicology information available for food-use pesticides (Knudsen et al.
Recent data have shown that many of the same synthetic and natural environmental chemicals that disrupt endocrine signaling in vertebrates also disrupt phytoestrogen-NodD receptor signaling in soil bacteria, which is necessary for nitrogen-fixing symbiosis.
In fact, a wide variety of natural and synthetic chemicals exist in the environment that mimic hormones and disrupt endocrine signaling in vertebrates through interaction with various nuclear receptors and signal transducer proteins, including the estrogen receptor (ER), orphan receptors, and the thyroid receptor (Cheek et al.
Our data present the first evidence that some of the same organochlorine pesticides and EDCs known to disrupt endocrine signaling
through ERs in exposed wildlife and humans also disrupt the phytoestrogen signaling that leguminous plants use to recruit Sinorhizobium meliloti soil bacteria for symbiotic nitrogen fixation.