High performance liquid chromatography of steroids in bovine adrenal glands: changes during the postpartum interval

High performance liquid chromatography was utilized to characterize changes in the content of various steroids in adrenal glands with time postpartum. Adrenal glands were obtained from 32 beef cows on either days, 7, 14, 28, 42 or 56 after parturition (n = 6-8/group). Of the major glucocorticoids, only cortisone significantly changed with time postpartum. Adrenal content of cortisone was 56% lower (P less than 0.05) on day 14 than on days 7, 28, 42 and 56. Average adrenal content (microgram/g) of cortisol, cortisone, corticosterone and 11-dehydrocorticosterone was 3.3, 2.4, 1.8 and 1.8, respectively. All other adrenal steroids measured were less than 0.8 micrograms/g. Correlation coefficients among the adrenal steroids measured indicated that terminal products (e.g. 11-dehydrocorticosterone and cortisone) of glucocorticoidogenesis were positively correlated (r = 0.56-0.64) with each other (P less than 0.05), whereas cortisone was negatively correlated (P less than 0.05) with both 17 alpha-hydroxyprogesterone (r = -0.49) and progesterone (r = -0.58). The latter suggests that a product (cortisone) inhibition mechanism may exist in bovine adrenal glucocorticoidogenesis. Collectively, these data suggest that cortisone should be considered a potential factor in the regulation of physiologic functions in postpartum cattle.