Metabolic effects of oral contraceptives in monkeys fed adequate protein and low protein diets.

The effects of 2 oral contraceptives Ovulen and Norlestrin were studied in monkeys fed adequate protein and low protein diets. The experiment was carried out in parts. In the first one the administration of contraceptives was cyclic and similar to that employed in human subjects. In the other experiments the contraceptives were given continuously and an attempt was made to exaggerate the deleterious effects of the oral contraceptive on the liver by including small doses of a known hepatotoxic agent aflatoxin (AT). In Experiment 1 45 female monkeys were divided into 2 groups of 20 and 25 and received an adequate protein (16%) and low protein diet (4%) respectively. Each monkey was fed 1/5 of a tablet of Ovulen or Norlestrin orally for 3 weeks and then administration was discontinued for 1 week. In Experiment 2 35 female monkeys were divided into 7 groups of 5 each. All the animals recieved 4% protein diet. 5 groups were tube fed at the rate of 100 cal/kg body weight while 2 groups were given diet ad libitum. Group I received the diet alone while groups II-V received 10 mcg AT 25 mcg AT 10 mcg AT plus 1/5 Ovulen tablets and 25 mcg AT plus 1/5 Ovulen tablet respectively daily. Groups VI and VII received the diet ad libitum but were orally fed 75 mcg AT and 75 mcg AT plus 1/5 Ovulen tablet respectively. Serum glutamic-oxalacetic transaminase activity and alkaline phosphatase activity were studied at regular intervals after the administation of oral contraceptives in the experiments. Serum proteins and hemoglobin were also determined. Monkeys fed oral contraceptives showed increased serum glutamic-oxalacetic transaminase and alkaline phosphatase activities irrespective of the level of protein in the diet. Livers of animals receiving oral contraceptives were morphologically similar to the controls fed respective diets. The experiments were conducted for a period of almost 2 years.