title: Effects of weaning on concentrations of inhibin in follicular fluid and plasma of sows.
abstract: Changes in plasma and follicular fluid concentrations of inhibin were examined in sows after weaning at 28-32 days post partum. From 0 to 48 h after weaning, inhibin concentrations were 200-300 times higher in follicular fluid from small (less than 4 mm) and medium-large (greater than or equal to 4 mm) follicles than in ovarian venous plasma. Inhibin concentrations increased in follicular fluid from medium-large follicles at 24 and 48 h after weaning; concentrations in ovarian venous plasma were positively correlated with the number of medium-large follicles (r = 0.40) and with ovarian venous plasma concentrations of oestradiol (r = 0.61). Blood samples were collected for 30 days from sows (n = 6) that exhibited oestrus within 5 days after weaning and from sows (n = 5) that remained anoestrous for 11 days after weaning. Plasma inhibin concentrations rose in oestrous and anoestrous sows by 12 h and continued to rise for 60 h after weaning. Plasma inhibin concentrations rose further and were higher at 3.5-4.5 days after weaning in oestrous sows than in sows that remained anoestrous. After oestrus, plasma inhibin concentrations declined. At weaning, plasma concentrations of follicle-stimulating hormone (FSH) were higher in sows that subsequently exhibited oestrus than in sows that remained anoestrous. After weaning, plasma concentrations of FSH declined in both groups, reached a nadir at 2.5 days, and increased gradually in anoestrous sows; oestrous sows exhibited an FSH surge at oestrus. Plasma FSH returned to preweaning concentrations in both groups of sows at Days 7-8.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: US Department of Agriculture, Roman L. Hruska US Meat Animal Research Center, Clay Center, Nebraska 68933-0166.
authors.forename: W E
authors.initials: WE
authors.lastname: Trout
authors.forename: J H
authors.initials: JH
authors.lastname: Killen
authors.forename: R K
authors.initials: RK
authors.lastname: Christenson
authors.forename: B D
authors.initials: BD
authors.lastname: Schanbacher
authors.forename: J J
authors.initials: JJ
authors.lastname: Ford
mesh_terms: D000818:Animals; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015571:Follicular Fluid / Q000737:chemistry*; D005498:Follicular Phase / Q000502:physiology; D007265:Inhibins / Q000032:analysis* / Q000097:blood; D010053:Ovary / Q000098:blood supply; D011374:Progesterone / Q000097:blood; D013552:Swine / Q000378:metabolism*; D014886:Weaning
chemical_list: D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D005640:Follicle Stimulating Hormone