[Experimental effect of tetracycline on the protein makeup of the lymph and blood serum].

The effect of tetracycline hydrochloride on the levels of total protein and separate protein fractions, such as albumins and alpha 1-, alpha 2-, beta- and gamma-globulins in the lymph and blood serum of rabbits was studied. The antibiotic was administered intramuscularly in a single dose of 25 mg/kg or repeatedly for 7 and 20 days. The lymph was collected from the thoracic duct 1, 1.5, 2, 2.5, 3, 3.5, 4 and 24 hours after the antibiotic administration in a single dose. When the antibiotic was used repeatedly, the lymph was collected 24 hours after the last injection. The levels of the total protein were determined colorimetrically and those of the protein fractions were determined turbidimetrically. The results indicated that under the experimental conditions tetracycline induced a marked decrease in the contents of both the total protein and the protein fractions in the lymph and blood serum of the animals. This phenomenon was observed in all periods. Comparative analysis of the data on the lymph and blood serum specimens collected from the same experimental animal revealed a difference in the albumin-globulin ratio, which was higher in the lymph and lower in the blood serum compared to that in the intact animals. This is indicative of the tetracycline capacity for decreasing mainly the levels of the globulin fraction in the lymph and the albumin fraction in the blood serum. The decrease in the level of the gamma-globulin fraction in the lymph and blood serum may be attributed to inhibition of the immune system function due to antibiotic therapy. Since maintenance of the albumin level is one of the liver important functions, the changes in the protein composition of the lymph provide an additional information on the effect of tetracycline on this function of the liver.