Plasma ammonia is the principal source of ammonia in sweat

Abstract

Sweat contains ammonia. However, neither its source nor factors affecting its concentration in the sweat are known. The aim of this study was to examine the effect of plasma concentrations of ammonia and urea on the concentration of ammonia in the sweat. Four groups of male volunteers were examined: one control, two after ingestion of ammonium chloride, three cirrhotic, hyperammonaemic, four uraemic. Sweat was collected from each subject from the palmar side of the forearm using gauze pads, after previous iontophoresis of pilocarpine. Ammonia and urea concentrations were determined in the sweat and in the plasma. It was found that elevated plasma ammonia concentration in healthy subjects after ingestion of ammonium chloride as well in the cirrhotic patients resulted in an increase of ammonia concentration in the sweat. High plasma and sweat urea concentration in the uraemic subjects did not affect the concentration of ammonia in the sweat. It was concluded that plasma ammonia was the principal source of ammonia in the sweat.

The microfluidics of the eccrine sweat gland, including biomarker partitioning, transport, and biosensing implications

“…More details can be found elsewhere. 23,61,62,64 Regardless, this protonation of ammonia is practically beneficial as it increases the concentration, which potentially simplifies sensor detection methods. 10 Ammonia is one example of many possible examples of molecules which could permeate the epithelial membrane of the eccrine sweat gland via diffusion and become entrapped within the lumen due to ionization.…”

“…24,61,62 Ammonia is also of interest because it is a possible and needed substitute for lactate measurement of anaerobic condition (see Subsection IV H). Ammonia (NH 3 ) passes through the cells lining the secretory coil by means of a passive diffusive mechanism.…”

Ammonia in breath and emitted from skin

“…Sweat ammonia, in turn, has three possible origins, (i) blood (skin/sweat pH is normally lower than blood pH, and the resulting pH gradient makes blood ammonia diffuse to the skin), (ii) the sweat gland (ammonia may diffuse both outwards to skin and inwards to blood), and (iii) hydrolysis of sweat urea by skin bacteria [54]. Previous research has excluded (iii) but is still divided whether most of the sweat ammonia originates from plasma [53,65,66] or the sweat glands [54]. Of the three types of sweat glands (eccrine, apocrine and sebaceous), eccrine glands, which have the highest density on palms and soles, then in decreasing order on head, trunk and extremities, produce most sweat ammonia [4].…”

Identification of Ammonia in Gas Emanated from Human Skin and Its Correlation with That in Blood

“…Because ammonia also exists in sweat 12 and in the atmosphere, the value of ammonia in the blood will give a higher value when these are mixed with blood. This problem was solved by thoroughly washing the finger as outlined above and taking the blood sample as quickly as possible.…”