Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/1998
Publication Date: N/A
Technical Abstract: Cortisol and aldosterone content and concentration in swine uterine flushings increased two- to sixfold between d 10 and 19 of porcine pregnancy with the greatest changes noted after d 13 (Klemcke et al., Biol. Reprod. 58:240, 1998). The current study was conducted to determine if these intrauterine increases in corticosteroids result from similar plasma increases. Four white crossbred gilts were catheterized on d 7-8 of pregnancy. On d 12 through 18, blood samples from these jugular catheters were obtained at 0700, 1100, and 1500 h. Using radioimmunoassay procedures, cortisol was directly measured in plasma samples, whereas aldosterone was measured after extraction of plasma with ethyl acetate and using 3H- aldosterone to measure procedural losses. Cortisol concentrations decreased daily between 0700 h and 1500 h (P = .056) reflecting the known diurnal rhythm of cortisol in pigs. Cortisol concentrations did not, however, change between d 12 (19.22 +/- 2.5 ng/ml) and d 18 (32.6 +/- 6.3; P = .48) of pregnancy. Plasma aldosterone concentrations did not change with time of day (P = .07), nor between d 12 (91.1 +/- 22.8 pg/ml) and d 18 (37.2 +/- 6.3 pg/ml; P = .37). These data strongly suggest that previously measured uterine increases in these corticosteroids represent intrauterine mechanisms rather than simply reflecting increases in plasma corticosteroids and subsequent diffusion of these steroids into the uterine lumen.