title: Hormone induced lactation in the bovine III. Dynamics of injected and endogenous hormones.
abstract: Three lactations were induced in two cows in two trials by twice daily subcutaneous injections for seven days. Each injection contained .05 mg/kg body weight of estradiol-17beta and .125 mg/kg body weight of progesterone. Included with the hormones in trial 1 was a combination of 233 muCi of [6,7-hydrogen-3] estradiol-17beta and 12 muCi of [4-carbon-14] progesterone. During trial 2,2050 muCi of [2,4,6,7 hydrogen-3] estradiol-17beta were incorporated with the hormones for one cow and 2344 muCi of [1,2,6,7 hydrogen-3] progesterone for the other. Radioactivity from hydrogen-3 and carbon-14 was detected in urine and feces but not in mammary secretion during trial 1. Isotope recovery from [hydrogen-3] estradiol-17beta was too low to quantify. By day 17, 90% of the carbon-14 from progesterone was accumulated in feces and 8.0% in urine. For trial 2, recoveries of radioactivity by day 28 from urine, feces, and mammary secretions were, respectively, 32.4, 56.2, and less than .002% from [hydrogen-3] estradiol-17beta and 6.0, 87.7, and .25% from [hydrogen-3] progesterone. Estrogen and progesterone in plasma averaged 1.83 and 2.61 ng/ml during days 2 to 7. Estrogen decreased more rapidly than progesterone post-treatment, but both had decreased by days 16 to 19 when average prolactin of plasma increased. Quantitative measures of estradiol 17-beta and progesterone absorption, whether in plasma or excreta, were correlated.
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004958:Estradiol / Q000378:metabolism / Q000494:pharmacology*; D004967:Estrogens / Q000378:metabolism; D005243:Feces / Q000032:analysis; D005260:Female; D007774:Lactation / Q000187:drug effects*; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism / Q000494:pharmacology*; D011388:Prolactin / Q000097:blood
chemical_list: D004967:Estrogens; D011374:Progesterone; D004958:Estradiol; D011388:Prolactin