Kratko priopćenje
Influence of lead on the activity of acethyl-cholinesterase
Ibrahim ruždić
; Institut za higijenu rada Zagreb
Sažetak
The fact that the properties of lead show certain similarity to those of calcium in human organism, and that the calcium ions enhance the activity of acetylcholine esterase, induced us to suppose that lead ions may have great Influence on choline esterase as well, namely, affect the sensibility and nervi-motor functions of the nervous system. Having this in mind, our first investigations started by finding out whether there is a difference between the activity of acetylcholine esterase serum of healthy people and that of the lead poisoned ones. Tests were carried out with workers who had more than 100 micrograms of lead in 100 ml blood. The acetylcholine chloride solution »Roche« served as substrate (basis) for determination of the activity of choline esterase; human serum was used as ferment. The reaction mixture always contained: 10 ml borate buffer, 0,2 ml serum, 10 ml 0,5% acetylcholine solution, and 4,8 ml redistilled water, giving the total of 25 ml. The hydrolysis took 3 hours at 37°C. The activity of acetylcholine esterase was determined by photometric measuring carried out in the following way: acetic acid was freed through hydrolysis of acetylcholinechloride and then bound to ferri ions; next we measured the intensity of the colour in a 5 cm cell with a S 57 filter (Stufen Photometer Zeiss). In these measurements the activity o:t choline esterase was represented by the value of extinction. Thus we determined the activity of acetylcholine esterase in serums of nine workers poisoned by lead. We found that the activity of acetylcholine esterase In the serum of a poisoned man is smaller than in the serum of a healthy man the former ranging between 0,01-0,05, and the latter between 0,08-0.12. Then we turned to investigations on the influence of lead nitrates on the activity of acetylcholine esterase in vitro. The reaction mixture contained: 10 ml borate buffer, 0,2 ml serum, 10 mI 0,5% acetylcholine solution. x ml lead nitrate solution containing 2 micrograms lead in one ml. and (4.8-x) ml redistilled water, giving a total of 25 ml. Other experimental conditions were the same as in former tests. From the data received by such method of determining the activity of acetylcholine esterase serum, we may draw the following conclusion: lead, - inasmuch it is in the form of lead nitrate and under afore-mentioned conditions, - may slightly enhance the activity of acetylcholine esterase. The average values of the activity are shown by curves. An increase of porphyrine in human organism is also characteristic for lead poisoning. We investigated the effector activity of porphyrine on acetylcholine esterase. It was observed that hematoporphyrine inhibits the activity of acetylcholine esterase. The results were only of qualitative nature since the titrimetric method which was used was not sensitive enough to give quantitative results. Further investigations on the activity of other lead salts on all kinds of choline esterase of human organisms are in progress.
Ključne riječi
Hrčak ID:
189427
URI
Datum izdavanja:
19.6.1950.
Posjeta: 692 *