Steroid vs Peptide Horomes

They are both a part of the endocrine system, which in itself says they are long-lasting and have slower effects.

The nervous system has rapid effects but are short.

Can you give the question? More info always helps

The answer probably comes down to structural differences. Steroid hormones are based on the basic steroid ring structure, while peptide hormones are, obviously, peptides made up of amino acids (and are therefore much bigger and have COOH and NH2 ends).

This is just a guess but I suspect your answer is something along the lines of steroid hormones being faster, since they are smaller and more lipid soluble. I could be wrong tho.

Steroid would be "longer lasting" because they have genomic effects, which means they have affects at the transcription level, and peptide hormones would be "shorter lasting" because they have a membrane receptor.

Hm, if I had to guess I'd say that peptide hormones would be slower buy longer acting because they tend to act through a second messenger system.

peptide hormones are definitely faster due to quick amplification via second messenger signaling

steroid hormones are longer and perhaps longer lasting due to transcriptional/translational regulation that is required in gene expression

Thanks. Biology is not my strong point

I came across an interview with Eric Kandel - nobel laureate physician/scientist - and a pioneer in memory research, where he discussed the difference in short VS long term memory formation. One key difference is that longterm memory requires genetic changes in neural cell bodies, transcription rates r altered leading to formation of new synaptic connections and thus greater memory permanence.. memory seems to be a electrical/neural circuit..

Now, I have been classically conditioned to associate longterm memory with steroid hormones.. so I can't help but mention this!!

Steroid Hormones
Effects are long lasting and slow
Synthesized in the Smooth ER and excreted directly into the blood, not stored
Diffuse through plasma members to bind cytoplasmic receptors in cells which cause uptake into the nucleus of the cell
In the nucleus the act as transcription promoters to regulate gene products thus their effects last for a long time
These are hydrophobic so they cannot dissolve in the blood and usually associate with other proteins for their transport mechanism

Peptide Hormones and Amino Acid Derivatives
Short Lasting effects and quick
Synthesized in the Smooth ER and packed and stored until needed
Bind surface cell receptors on cells
Use a second messenger system such as CAMP to active cascades which multiple the effectiveness of the hormone
Their effects are short lives
They are also hydrophilic so they can dissolve in the blood
*Exception to the rule - Thyroid Hormone (Thoraxin) Modified AA derivative can bind cytoplasmicly

Now you just gota remember which ones come from where lol.

Any more questions just ask away if not, have a good one!

I think it's a bad question, typical for Kaplan. Peptide hormones can have effects that are long-lasting too. Insulin-like growth factor 1 has permanent effects on bone length and on the development of many other cells. It's just that the effects of steroid hormones usually can't be reversed unlike many peptide hormones. For example, estradiol secretion during puberty will make women grow breasts; if you lower the estradiol, the breasts will still be there. With a peptide like epinephrine, there will be a temporary increase in blood pressure, heart rate, glucose, etc. but the body will return to a normal physiological state once the concentration is reduced.

I doubt such a **** question would ever come up on the MCAT. The "most correct" answer would be steroids though.

You're supposed to think for the MCAT of something like ADH (peptide) happening relatively quick as opposed to testosterone having you go through puberty over the course of several years.