The detection of nucleotide sequences with strong similarity to hormone responsive elements in the genome of eubacteria and archaebacteria and their possible relation to similar sequences present in the mitochondrial genome

To account for the presence of nucleotide sequences in mitochondria with similarity to the Hormone Response Elements (HREs) of the nuclear genomes of man, rat and mouse, the genomes of several. procaryotes have been screened for the presence of the sequences AGAACA NNN TGTTCT and GGTACA NNN TGTTCT, which represent perfect palindromic and consensus class I HREs, respectively, and for the sequence AGGTCA NNN TGACCT, which represents class II HRE. In many of the examined procaryotes, eubacteria and archaebacteria, almost perfect palindromic class I HREs and perfect or almost perfect class II half palindromic HREs have been detected in various genes, some of which encode proteins involved in energy metabolism, in replication and in transcription control. These findings support the hypothesis that the similar sequences found in mitochondria, potentially involved in, hormonal regulation of respiratory enzyme biosynthesis, were introduced into eucaryotic cell by the procaryotic endosymbionts

Steroid receptors in the uterus: Implications in endometriosis

Receptor proteins for estrogens, progesterone, androgens, and glucocorticoids have been detected in the various cell types of the uterus. Reference is made to the genes encoding these receptors, to the structure of the receptor proteins, and their functional domains. The mode of action of steroid hormones by gene activation, through their cognate receptors, and by nongenomic effects is briefly presented. The role of the steroid receptors in uterine physiology and the significance of the use of steroid receptor knock-out animals in delineating the in vivo action of the hormones is discussed. Recent results on the possible correlation of steroid receptor gene polymorphisms and of quantitative and qualitative changes in the receptor proteins to the etiopathology of endometriosis are reviewed

Estrogen and progesterone receptors in the endometrium

The endometrium, as a target of estrogens and progestins, possesses the respective receptor proteins. These receptors belong to the superfamily of nuclear receptors, having important functional domains required for steroid ligand binding, for dimer formation, for interaction with HREs of DNA, for transcription modulation, for association with other proteins, for intracellular trafficking, and other activities. The mechanism of action of the steroid hormones involves modulation of gene activity through interaction of the hormone-receptor complex with HREs and with other nuclear proteins, but also encompasses nongenomic effects, which accounts for the rapid effects of the steroids on cellular functions. Antihormones-antiestrogen and antiprogestins-compete with their respective hormones for binding sites on the receptor molecules. Some antihormones are partial agonists. The molecular mechanisms underlying the dual behavior of antihormones is under consideration. The concentration of ER and PR in different physiological and pathophysiological states, such as the menstrual cycle, pregnancy, and endometrial cancer, has been determined by biochemical and immuno(cyto)chemical methods. The levels of estrogens and progestins are important regulators of ER and PR gene expression. Estradiol acts as a cell mitogen, inducing key genes involved in replication, and its tumor promoter effect is discussed in this sense, whereas progesterone has reverse effects when compared to estradiol and acts as a differentiation factor. The cross-talk between the endocrine system, growth factors, and neurotransmitters can take place both at the receptor level, involving mainly phosphorylation reactions, and at the gene level, mainly through protein-protein interactions

Differential Binding of 14C-Cortisone in Fetal, Placental, and Maternal Liver Tissue in A/Jax and C57BL Mice

When 14C-cortisone was given to pregnant A/Jax and C57BL mice, the concentration of radioactivity firmly bound to fetal tissue was significantly higher in A/Jax mice than in C57BL mice. Differences in the binding of cortisone to tissue proteins may explain the differential incidences of cleft palate in A/Jax and C57BL mice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67663/2/10.1177_00220345720510052901.pd