Hi all. I know steroid hormones diffuse inside the cell to affect related receptors . But what about non-target cells? Can they be used as energy source in anaerobic respiration? Or do they just diffuse-outside as they came in ?

Thanks and cheers .

Because of their lipophilic nature, free steroid hormones enter target cells by passive diffusion through the cell membrane. After gaining entry to the cell, steroid hormones act as ligands for nuclear receptors and alter gene transcription. There is also recent evidence that receptor-mediated uptake of steroid hormones, bound to their carrier proteins, may play a role in steroid metabolism, although the physiological significance of such pathways is still unclear.

I am unaware of any data to indicate that steroid hormones are used as an energey source as you suggest.

see
https://en.wikipedia.org/wiki/Steroid_hormone_receptor
http://www.sciencedirect.com/science/ar … 2299803005

Just to add, there is also evidence that steroid hormones such as cortisol, aldosterone and oestrogen may act at, or near, the cell surface (or other intracellular sites) involving 'fast' activation of second messengers such as calcium, cAMP and other pathways. The type(s) of receptors involved in these 'non-transcriptional' effects is hotly debated, e.g., they could be 'nuclear' receptors or variants thereof acting outside the nucleus, or novel receptors. An example of the latter appears to be the G protein-coupled oestrogen receptor, GPER.