As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why are only specific cells responsive against steroid hormones?

For example, all of our body cells almost contains the genes for the development of secondary sexual characters but why do only specific cells show a response against these steroid hormones because the development of secondary sexual characters occur only in specific region of our body, that is, beard formation occur only in a specific region of the face, etc.

IN SUMMARY: When steroid hormones can pass through every cell of our body then why do they show only a localized response?


2 Answers 2


The quick answer is that only certain cell types express the required steroid hormone receptors that are necessary to induce signaling and gene regulation when bound to their target steroid hormones, like estrogen, testosterone, cortisol, etc. If no receptor is present, the steroid doesn't effect any change.

The second part of the answer involves the particular signaling pathways induced by the ligation of certain receptors by certain classes of hormones. Testosterone, for example, has numerous effects across the body, from promoting the growth of hair to building muscle mass to effects on mental well-being. Testosterone and its primary metabolite 5α-dihydrotestosterone bind primarily to the cytoplasmic androgen receptor, which then translocates to the nucleus, binds DNA at hormone response elements, and alters the transcriptional activity of genes (either increasing or decreasing, depending on the gene and the cell type). Testosterone can also be metabolized to estradiol and bind estrogen receptors, which function similarly to the androgen receptor (although it can have DNA-independent effects as well).

So, depending on the cell type, receptor expression levels, other DNA regulatory elements, the presence or absence of various testosterone-metabolizing enzymes, and other factors like age, gender, etc., a single steroid hormone can have a multitude of effects throughout the body.


Unlike other types of hormones, steroid hormones do not have to bind to plasma membrane receptors. Instead, they can interact with intracellular receptors that are themselves transcription activators. Steroid hormones too hydrophobic to dissolve readily in the blood travel on specific carrier proteins from their point of release to their target tissues. In the target tissue, the hormone passes through the plasma membrane by simple diffusion and binds to its specific receptor protein in the cytoplasm. The receptor-hormone complex then translocates into the nucleus where it acts by binding to highly specific DNA sequences called hormone response elements (HREs), thereby altering gene expression. Hormone binding triggers changes in the conformation of the receptor proteins so that they be- come capable of interacting with additional transcription factors. The bound hormone-receptor complex can either enhance or suppress the expression of adjacent genes. The DNA sequences (HREs) to which hormone- receptor complexes bind are similar in length and arrangement, but differ in sequence, for the various steroid hormones. Each receptor has a consensus HRE sequence to which the hormone-receptor complex binds well, with each consensus consisting of two six-nucleotide sequences, either contiguous or separated by three nucleotides, The ability of a given hormone to act through the hormone-receptor complex to alter the expression of a specific gene depends on the exact sequence of the HRE, its position relative to the gene, and the number of HREs associated with the gene.


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