Article Text

PDF

Effect of oxytetracycline administration on intestinal metabolism of oestrogens and on plasma sex hormones in healthy men.
  1. E Hämäläinen,
  2. J T Korpela,
  3. H Adlercreutz

    Abstract

    The effect of oxytetracycline (1 g/day for five days) on the enterohepatic recycling of oestrogens and on plasma sex hormone concentrations was assessed in healthy men. Plasma oestrone (E1), oestradiol-17 beta (E2), 4-androstenedione (A), 5 alpha-dihydrotestosterone (5 alpha-DHT), total and free testosterone (T and free T), binding capacity of sex hormone binding globulin, luteinizing hormone, dehydroepiandrosterone-sulphate, urinary total E1, E2, and oestriol (E3), and oestriol-3-glucuronide (E3-3G) and faecal unconjugated and conjugated E1, E2, and E3 were measured by radioimmunoassay (RIA). Treatment with the antibiotic significantly increased the excretion of faecal conjugated oestrogens, which parallelled a decrease in urinary oestrogen excretion, especially of E3. The effect on urinary E3 could be explained almost entirely by the simultaneous decrease of urinary E3-3G concentrations. In urine and faeces the E2/E3 and E1 + E2/E3 ratios increased, probably because of the diminished reductive metabolism of oestrogens in the gut. No significant effects on plasma unconjugated oestrogen concentrations were observed. Moreover, in the present study oxytetracycline had no remarkable effect on plasma total, or free T concentrations, nor on other plasma hormones measured. Our results suggest that enterohepatic recycling and intestinal metabolism of oestrogens may be significant in men. The mechanism of action of antibiotics on oestrogen metabolism probably involves decreased hydrolysis by beta-glucuronidase of oestrogen conjugates by the intestinal contents, diminishing the reabsorption of aglycones of oestrogen conjugates and resulting in faecal loss of the steroids.

    Statistics from Altmetric.com

    Request permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.