I'm having trouble finding the differences between steroid and peptide hormones, can anyone explain them to me

Answer 1

This is just a rough sketch, but I needed a little refresher in this for endocrinology. Hope it helps!

Answer 2

There are two major differences.

1. structure - peptide hormones are made of just that, peptides! Steroid hormones have a cholesterol base, if you look online, you'll find a picture of the structure.

2. mechanism - peptide bonds interact with surface receptor molecules on cells, and work via signal transduction (G-proteins, IP3/DAG pathway, MAP-kinase pathway, tyrosine-kinase receptors, etc.). These pathways ultimately end up increasing or decreasing transcription by way of transcription factors, but they never actually enter the cell! Steroid hormones DO IN FACT enter the cell and inside the cell directly interact with transcription factors to upregulate or downregulate transcription of a gene.

Answer 3

There are a lot of differences, but I think the biggest difference is they way they effect the cell. The steroid hormone is lipid soluble, so it crosses through the cell membrane directly into the cell. The peptide hormone is not lipid soluble, so it lands on the cell membrane receptor, and it's affect on the cell is caused by the "second messenger system"

Answer 4

In addition to above, peptide hormones can be directly released to bloodstream and travel around freely. Steroid hormones require a protein transport to couple to for reaching their destination.