Urinary antidiuretic hormone excretion during the menstrual cycle and pregnancy in the monkey

24 urine collections were made in normally cycling and pregnant adult female rhesus monkeys. Volume and osmolality were measured and the antidiuretic hormone (ADH) excretion was determined by a radioimmunoassay of extracted urine. No differences were found between pre and post ovulatory monkeys and between nonpregnant and pregnant monkeys. Mean urinary ADH excretion in nonpregnant monkeys was 4.06±0.82 mU/24 hr. The concentration of ADH in the urine of the monkey is similar to that in the urine of the normal human. ADH can be readily detected in the urine of the monkey. Measurement by radioimmunoassay may provide a means of directly assessing neurohypophysial function in these animals.