Selective progesterone receptor modulators (SPRMs) represent a class of progesterone receptor ligands that display progesterone agonist, antagonist, or mixed agonist/antagonist activity on several progesterone target tissues [ 117].
Hyperglycemia in type 2 diabetes results from a combination of insulin resistance in several insulin target tissues (including liver, skeletal muscle, and adipose tissue) and β-cell dysfunction (1, 2).
Because ER proteolysis is probably relevant to several oestrogen target tissues, we suggest that the protein environment, which differs among tissues, may be a factor of major importance in the formation of distinct oligomeric structures, which elicit specific biological responses.
Although we identified several novel target tissues for estrogens, we used only one type of ERE and surrounding sequence, which will not be effective for all estrogenic signaling systems.
No study has yet attempted to compare several target and non-target tissues in order to define the critical events subsequent to DNA damage and mutation that may determine carcinogen organotropism.
In this manner, AKRs regulate the occupancy and transactivation of several steroid receptors in target tissues leading to transcription of hormone-responsive genes [ 13].
As discussed, T cells specific for lytic viral antigens can accumulate in the inflammatory target tissues in several autoimmune diseases.
Although other isoforms, including MT2A, MT1E, and MT1G, are also functional (West et al. 1990), their ability to bind heavy metals, as with the MT1A isoform, depends on several factors: MT abundance in target tissues, mercury form in target tissues, and redox chemistry of MT and thiolate (Maret and Vallee 1998).
In utero DES exposure alters methylation patterns of several genes in estrogen's target tissues, including Hox genes [ 72, 73], c-fox [ 74], and Nsbp1 [ 75], but it has not been studied whether changes in methylation patterns occur in the mammary gland.
