Steroid hormones cortisol, testosterone and oestradiol are transported by passive diffusion through the acinii and so are NOT affected by saliva flow rate. Other peptide hormones move between cells by ultrafiltration and these you will have to keep note of the volume of saliva produced with time.

Steroid hormones cortisol, testosterone and oestradiol are transported by passive diffusion through the acinii and so are NOT affected by saliva flow rate. Other peptide hormones move between cells by ultrafiltration and these you will have to keep note of the volume of saliva produced with time.

Do you have any references that actually establish that flow rate doesn't affect steroid levels in the saliva? I know it is an article of faith among salivary researchers that flow rate doesn't affect steroids, but I haven't seen this validated.

The two classic papers cited are by Vining and Riad-Fahmy.

...

Mazen,

Thanks for the links. I had not read those articles. I think they answer some of my questions, but not all. In particular I am concerned that the studies used very specific collection procedures that do not duplicate how salivary samples are collected. They pipetted directly from parotid glands and didn't collect mixed saliva as is common in sampling saliva. The other concern is that the data are for C-21 steroids, cortisol and progesterone, with limited data on C-19 testosterone and nothing on C-18 estradiol. Do you know of any studies that have looked at flow rate and T or flow rate and estradiol?

I think the data are clear when one precisely collects parotid saliva that Cort is not affected by parotid flow rate, but I am not sure that one can generalize this to steroids in mixed saliva samples.

Hi Kim,

Yes the optimal collection procedures were not yet known back in the early 1980s and, unfortunately, even today some of these collection procedures are still being used and published (e.g. using cotton-based materials to collect saliva from a particular gland). However, the literature shows good correlations with saliva and blood cortisol.

I have no record of any other papers who have experimental evidence on salivary flow rate effect on these steroids, every paper I have seen pretty much cites Vining et al. Most authors assume that small lipophilic molecules will pass through membranes via passive diffusion. I agree that re-validating flow rate and steroid concentrations using today's methods (i.e. unstimulated passive drool) would be useful.

If you do come across anything please let me know.

Cheers,

Mazen

Mazen,

In my searches I have not found any study that uses real-world flow rates. In the classic studies flow rate was increased using citric acid, which I suspect is markedly different than the changes in flow rate that occur with physical exercise. I think colleagues here at Emory are trying to get data on how physical exertion alters flow rate and whether that relates at all to the levels of salivary hormones detected.

From my reading of the literature I am concerned that Cort may be different than other lipophilic steroids. For example, salivettes don't appear to affect Cort levels, but they do affect detected T levels and differently in men and women. I am not sure we can treat any steroid as representative of all steroids and it is likely that each steroid has top be measured and investigated separately. The fact that studies report comparable salivary levels of E2 in men and women, whereas serum levels differ by a minimum of a factor of two is cause for concern. I recently saw a paper where men and women had the same levels of salivary T, when the men's serum T had to be a least an order of magnitude greater. I think there is so much we don't know about salivary hormones and won't be surprised if somewhere down the road a lot of results have to be discarded when we learn the factors that really are affecting salivary levels.

Thanks for your insight.

Kim

Thanks Kim. I'm sure we can discard some of the papers already, although there are so many conflicting results it is hard to tell which ones are correct.

Now that you highlight this lack of data specifically for T and E2 flow rates, I might try keep a record of flow rate in my future collections to get some data on this (I wish I did this from the beginning!). From my experience, flow rate is highly variable between individuals, especially when some have deficient salivary glands due do some endocrinological abnormality.

Could you give me a reference or two showing same E2 levels in males and females please? It might be due to the age range of both cohorts, for example post-menopausal women and men or pre-pubertal males and females will have similar levels, or possibly if the E2 levels are too close to the lower level of quantification to tell the difference.

Mazen