904 



7. MERCURIALS 



level producing the maximal K+ loss and inhibition of glucose utilization 

 (6.0-7.5 X 10"^^ mole Hg/cell), it is claimed that the fragility is decreased, 

 which it is in very hypotonic media, but examination of the curves shows 

 that some hemolysis (probably around 2-5%) has occurred in normal me- 

 dium. At a higher level of bound Hg++, where the effects on K+ and glu- 

 cose have been partly reversed (7.6 X 10~^^ mole Hg/cell), fragility is 

 definitely increased, and some 20% hemolysis has occurred in the normal 

 medium within 3 min. It seems clear, therefore, that the K+ loss and sup- 

 pression of glucose utilization at lower levels of bound Hg++ (left of the 



50- 



40 



30 



20 



10 



1000 



MOLES Hg BOUND/RBC « 10 



Fig. 7-41. Effect of Hg++ on the loss of K+ from human erythrocytes 

 and the uptake of glucose. (From Weed et al., 1962.) 



maximum in Fig. 7-41) are due almost entirely to effects on all the cells 

 and not on lysis of a fraction of the cells. However, at higher levels of 

 bound Hg++, lysis must contribute to both K+ loss and interference with 

 glucose utilization; e.g., at 7.6 X 10~^^ mole Hg/cell bound, there is 20% 

 lysis and around 20% loss of K+. If this is so, the disappearance of the 

 effect on K+ loss from intact cells must occur even more precipitously than 

 appears in the figure (the reversal is, of course, really not precipitous, since 

 it is a logarithmic scale; to reverse these effects appreciably it requires the 

 binding of about 10 times that amount of Hg++ necessary for maximal K+ 

 loss). The results of Jacob and Jandl (1962), also on human erythrocytes, 

 are quite different, since they observed that p-MB does not inhibit glucose 

 uptake or lactate formation — indeed, stimulates these somewhat — up to 

 5 //moles p-MB/ml of cells, which is around 2 x 10"^^ mole 2>-MB/cell. 

 There is also no reaction of p-MB with the intracellular glutathione. These 

 results point to a failure of p-MB to penetrate through the membrane. 

 Hemolysis occurs and is presumably due to an action on the membrane. 

 However, it is rather strange that sufficient mercurial can be bound to the 



