Pregnant mare serum gonadotrophin: rate of clearance from the circulation of sheep.

The process involved in the disappearance of PMSG from the blood of sheep, following a single intravenous injection, has been separated into two exponential components. Values (mean plus or minus S.E.) calculated from experiments on five animals were: metabolic clearance rate (37.8 plus or minus 1.6 ml hr-minus 1); rate constant of disposal (0.0315 plus or minus 0.0016 hr-minus 1); half-time of disposal (21.2 plus or minus 1.1 hr). The stage of the oestrous cycle, ovariectomy and the dose of PMSG used had no apparent effect on these values.