THE EFFECT OF ACTH INJECTIONS ON PLASMA CORTICOSTEROID LEVELS AND MILK YIELD IN THE COW

Abstract

SUMMARY In the cow, a single injection of adrenocorticotrophic hormone (ACTH) was found to produce a rapid rise in plasma 17:21-dihydroxy-20-keto-corticosteroids, and then an equally rapid fall. This was followed by a more gradual fall to pre-injection levels which were reached within 24–48 hr of the start of the experiment. The presence of cortisol in the blood samples was confirmed by chromatographic examination. Detectable amounts of other corticosteroids were not found. The ACTH injections produced a very definite fall in milk yield. Return to generally steady levels took 3 days in one case and more than 7 days in another.