Effect of certain antibiotics of tetracycline series on the level of blood sugar and the role of insulin in the mechanism of its regulation]

Experiments on male rats showed enterally administered tetracycline and chlortetracycline to promote an elevation of the blood sugar level. These antibiotics administered once together with glucose retarded the normalization of the blood sugar concentration. After 7-day administration of tetracycline and chlortetracycline glucose load caused a stable hyperglycemia. Special experiments with depancreatization and insulin injection to the animals and also the intravenous injection of glucose and the antibiotic demonstrated that the changes in the blood sugar concentration under the effect of tetracycline were associated both with its inhibitory action on the absorbing function of the intestine and with the retarded glucose utilization in the tissues. Insulin injected intramuscularly eliminated the hyperglycemic effect caused by the antibiotics.