Changes in concentrations of follicular inhibin alpha and beta A subunit messenger ribonucleic acids and inhibin immunoactivity during preovulatory maturation in the pig.
Ovarian tissues were collected from 5 pigs on each of days 1, 3, 5, and 7 after withdrawal of an orally active progestin to determine changes in follicular inhibin subunit mRNAs during preovulatory maturation. Follicles (N = 146) were aspirated for fluid and homogenized in guanidinium isothiocyanate for RNA isolation. Follicular RNA and inhibin alpha and beta A subunit mRNA standards were dot-blotted, hybridized with [32P]-cDNA probes, and quantified by densitometry. Mean concentrations of alpha mRNA (pg/micrograms of RNA) increased (p < or = 0.05) by 140% as healthy follicles grew from medium (3-5 mm) to large (> 5 mm). Inhibin immunoactivity was greater (p < or = 0.05) in large than medium follicles. In contrast, mean concentrations of inhibin beta A subunit mRNA did not differ between healthy medium and large follicles. However, both alpha mRNA and beta A mRNA increased (p < or = 0.05) linearly as follicular diameter increased from 3 to 5 mm on Day 1 and from 3 to 9 mm on Day 3. On Day 5, alpha mRNA remained elevated, but was not significantly correlated with diameter. In contrast, beta A mRNA decreased linearly (p < 0.05) as diameter increased from 6 to 11 mm on Day 5. The molar ratio alpha mRNA to beta A mRNA was 20:1 in healthy, large follicles on Days 3 and 5. Mean concentration of alpha mRNA in large follicles decreased (p < 0.05) by 72% between Days 5 and 7, while beta A mRNA decreased to non-detectable levels on Day 7.(ABSTRACT TRUNCATED AT 250 WORDS)
Guthrie
H D
HD
Agricultural Research Service, Livestock and Poultry Science Institute, Beltsville, Maryland 20705.
Rohan
R M
RM
Rexroad
C E
CE
Cooper
B S
BS
D000704:Analysis of Variance; D000818:Animals; D015152:Blotting, Northern; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D005498:Follicular Phase / Q000378:metabolism*; D007265:Inhibins / Q000096:biosynthesis*; D006080:Ovarian Follicle / Q000378:metabolism*; D010060:Ovulation / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis; D045167:Progesterone Congeners; D012333:RNA, Messenger / Q000096:biosynthesis*; D013552:Swine / Q000502:physiology*; D013739:Testosterone / Q000096:biosynthesis; D014204:Trenbolone Acetate / Q000031:analogs & derivatives
D045167:Progesterone Congeners; D012333:RNA, Messenger; C023445:altrenogest; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D014204:Trenbolone Acetate