Relationship between follicular development and the decline in the follicle-stimulating hormone surge in heifers

被引:40
作者
Gibbons, JR
Wiltbank, MC
Ginther, OJ
机构
[1] Univ Wisconsin, Dept Anim Hlth & Biomed Sci, Madison, WI 53706 USA
[2] Univ Wisconsin, Dept Dairy Sci, Madison, WI 53706 USA
关键词
D O I
10.1095/biolreprod60.1.72
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Experiment 1 was conducted to determine whether progesterone affects the pattern of the FSH surge or follicular development associated with a follicular wave in heifers. On Day 7 (Day 0 = ovulation), heifers were allocated into a group receiving prostaglandin F-2 alpha (PGF(2 alpha); n = 6) or a control group (n = 5). Twenty-four hours later, all detectable follicles (greater than or equal to 2 mm) were ablated (Hour 0). Follicular development was monitored Hours 0, 3, 6, 9, 12, and 16, at 8-h intervals thereafter until Hour 112. To monitor FSH concentrations, blood was sampled at Hours -24, 0, 3, 6, 9, 12, and 16, and at 8-h intervals thereafter until Hour 104. There were no differences (p > 0.05) between the PGF(2 alpha)-treated group and controls in the patterns of the FSH surge or follicular development. Experiment 2 tested the hypothesis that 3-mm follicles do not have FSH-suppressing capacity and that suppression increases as follicles grow beyond 5 mm. Twenty-four hours after an injection of PGF(2 alpha) (Days 6-8), heifers were subjected to either ablation of follicles greater than or equal to 2 mm or ovariectomy. Intact heifers were allocated into four groups (n = 5) in which all follicles of the new wave were ablated upon reaching either 3, 5, or 7 mm or were not ablated (controls). Blood was sampled at 8-h intervals to monitor FSH and estradiol-17 beta. Averaged over Hours 8-120, FSH concentrations (ng/ml) were higher (p < 0.05) in the ovariectomized (2.02 +/- 0.05) and the 3-mm groups (1.91 +/- 0.05) than in the 5-mm (1.52 +/- 0.05), 7-mm (1.35 +/- 0.04), and control groups (1.33 +/- 0.05); and estradiol concentrations (pg/ml) were lower (p < 0.05) in the ovariectomized group (0.19 +/- 0.03) than in the 3-mm (1.48 +/- 0.16), 5-mm (1.56 +/- 0.15), 7mm (2.22 +/- 0.27), and control groups (2.55 +/- 0.49). In conclusion, the presence of endogenous progesterone did not affect FSH patterns or follicular development. Follicles less than or equal to 3 mm had no detectable capacity to suppress FSH. As follicles grew from 3 to 5 mm, they gained the capacity to suppress FSH; however, as follicles grew beyond 5 mm, FSH-suppressing capacity did not increase. The FSH decline was not attributable to an increase in circulating estradiol.
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页码:72 / 77
页数:6
相关论文
共 28 条
[11]   Norgestomet implants maintain pregnancy in ovariectomized heifers [J].
Kesler, DJ .
THERIOGENOLOGY, 1997, 48 (01) :89-98
[12]  
Ginther OJ, 1996, J REPROD FERTIL, V108, P271, DOI 10.1530/jrf.0.1080271
[13]   COMPOSITION AND CHARACTERISTICS OF FOLLICULAR WAVES DURING THE BOVINE ESTROUS-CYCLE [J].
GINTHER, OJ ;
KASTELIC, JP ;
KNOPF, L .
ANIMAL REPRODUCTION SCIENCE, 1989, 20 (03) :187-200
[14]  
GINTHER OJ, 1989, J REPROD FERTIL, V87, P223, DOI 10.1530/jrf.0.0870223
[15]   Selection of the dominant follicle in cattle [J].
Ginther, OJ ;
Wiltbank, MC ;
Fricke, PM ;
Gibbons, JR ;
Kot, K .
BIOLOGY OF REPRODUCTION, 1996, 55 (06) :1187-1194
[16]   RELATIONSHIPS BETWEEN THE LEVEL OF ATRESIA AND INHIBIN CONTENTS (ALPHA-SUBUNIT AND ALPHA-BETA DIMER) IN MORPHOLOGICALLY DOMINANT FOLLICLES DURING THEIR GROWING AND REGRESSING PHASES OF DEVELOPMENT IN CATTLE [J].
GUILBAULT, LA ;
ROUILLIER, P ;
MATTON, P ;
GLENCROSS, RG ;
BEARD, AJ ;
KNIGHT, PG .
BIOLOGY OF REPRODUCTION, 1993, 48 (02) :268-276
[17]   CHANGES IN EXPRESSION OF INHIBIN/ACTIVIN-ALPHA, INHIBIN/ACTIVIN-BETA(A), AND INHIBIN/ACTIVIN-BETA(B) SUBUNIT MESSENGER RIBONUCLEIC-ACIDS FOLLOWING INCREASES IN SIZE AND DURING DIFFERENT STAGES OF DIFFERENTIATION OR ATRESIA OF NONOVULATORY FOLLICLES IN COWS [J].
IRELAND, JLH ;
IRELAND, JJ .
BIOLOGY OF REPRODUCTION, 1994, 50 (03) :492-501
[18]   IMMUNONEUTRALIZATION OF INHIBIN AND ESTRADIOL DURING THE FOLLICULAR PHASE OF THE ESTROUS-CYCLE IN COWS [J].
KANEKO, H ;
NAKANISHI, Y ;
AKAGI, S ;
ARAI, K ;
TAYA, K ;
WATANABE, G ;
SASAMOTO, S ;
HASEGAWA, Y .
BIOLOGY OF REPRODUCTION, 1995, 53 (04) :931-939
[19]  
LAW AS, 1992, J REPROD FERTIL, V96, P603, DOI 10.1530/jrf.0.0960603
[20]  
MARTIN GB, 1988, J REPROD FERTIL, V82, P319, DOI 10.1530/jrf.0.0820319