scholarly journals Dihydrotestosterone influenced numbers of healthy follicles and follicular amounts of LH receptor mRNA during the follicular phase of the estrous cycle in gilts

Reproduction ◽  
2008 ◽  
Vol 135 (3) ◽  
pp. 343-350 ◽  
Author(s):  
H Cárdenas ◽  
E Jiménez ◽  
W F Pope
Keyword(s):  
Estrous Cycle ◽  
Corn Oil ◽  
Follicular Phase ◽  
Lh Receptor ◽  
Receptor Mrna ◽  
Gonadotropin Receptor ◽  
Treatment Dose ◽  
Recruitment And Selection ◽  
Estradiol 17Β ◽  
Receptor Inhibitor

The present experiments were conducted to determine androgenic effects on numbers, health, and amounts of gonadotropin receptor mRNA in late developing follicles of gilts. Gilts (n=5 per group) received daily injections of one of the following treatments on days 13–16 or days 13–18 of the estrous cycle: corn oil, 5α-dihydrotestosterone (DHT, 10 mg), flutamide (1.5 g, an androgen receptor inhibitor), DHT (10 mg) plus flutamide (1.5 g), testosterone (10 mg), and testosterone (10 mg) plus flutamide (1.5 g). Ovarian follicles ≥5 mm in diameter were evaluated on day 17 or 19, 24 h after receiving the last treatment dose. Follicles were classified as healthy (H), moderately atretic (MA), or very atretic (VA). Treatment with DHT increased (P<0.05) the numbers of H follicles relative to control gilts on days 17 and 19. DHT administration from days 13 to 16 diminished (P<0.05) the amounts of LH receptor (LHR) mRNA in H follicles from day 17 (relative amounts: 1.45±0.33 and 2.72±0.33 for DHT- and vehicle-treated gilts respectively). The effects of DHT on numbers of H follicles and LHR mRNA were not observed in gilts receiving DHT plus flutamide. Androgens did not influence numbers of MA, VA, and total follicles, or follicular estradiol-17β concentrations and amounts of FSHR mRNA. Treating gilts with DHT during follicular recruitment and selection did not induce changes in the numbers of total follicles ≥5 mm, but rather increased the numbers of healthy follicles in this follicular population in association with decreased amounts of LHR mRNA.

Effects of exogenous steroid hormones on the dominant follicle maintained by a Norgestomet implant in heifers

1994 ◽  
Vol 74 (3) ◽  
pp. 457-464 ◽  
Author(s):  
R. Rajamahendran ◽  
M. Manikkam
Keyword(s):  
Corn Oil ◽  
Pulse Amplitude ◽  
Follicular Phase ◽  
New Wave ◽  
Dominant Follicle ◽  
Serum Lh ◽  
Plasma Steroids ◽  
Follicle Atresia ◽  
Estradiol 17Β ◽  
Altered Serum

The maintenance of the dominant follicle during the follicular phase by a 9-d Norgestomet implant was used to study the effects of progesterone (P4), estradiol-17β (E2) and testosterone (T) on follicular turnover in heifers. From day 4 of Norgestomet treatment, heifers (n = 16) were injected daily for 4 d with corn oil (control), 150 mg P4, 10 mg E2 or 200 mg T (n = 4 per treatment). Follicular changes were monitored daily by ultrasonography. Plasma steroids and serum LH were measured by validated radioimmunoassays. In control heifers, dominant follicles were maintained during implantation and ovulated after implant removal. In both P4- and T-treated heifers, dominant follicles began to regress during the implant period and the dominant follicle from a new wave of follicles ovulated. In E2-treated heifers, dominant follicles regressed (3/4) and dominant follicles from the next wave ovulated. The dominant follicle became cystic in the fourth E2-treated heifer. Mean serum LH levels were suppressed (P < 0.01) from 0.55 ± 0.01 ng mL−1 (mean ± SEM) in control to 0.21 ± 0.02, 0.19 ± 0.02 and 0.43 ± 0.02 in P4-, E2- and T-treated heifers, respectively. The number of LH pulses in 8 h was reduced (P < 0.01) from 6.25 ± 0.75 in control to 2.00 ± 1.00 and 4.66 ± 0.35 in P4- and E2-treated heifers but not in T-treated heifers (6.33 ± 1.44). LH pulse amplitude (ng mL−1) was also suppressed (P < 0.01) in P4-treated (0.10 ± 0.04) and E2-treated (0.09 ± 0.02) heifers when compared with control heifers (0.41 ± 0.04) but not in T-treated heifers (0.42 ± 0.17). Exogenous P4 and E2 caused regression of the Norgestomet-maintained dominant follicle, and this effect was associated with altered serum LH profile. Injection of T caused atresia of the dominant follicle without altering the LH profile. Key words: Dominant follicle, atresia, heifers, steroids, LH, ultrasound, E2, estradiol-17β; P4, progesterone; T, testosterone

scholarly journals Immunoneutralization of Inhibin and Estradiol during the Follicular Phase Of the Estrous Cycle in Cows1

1995 ◽  
Vol 53 (4) ◽  
pp. 931-939 ◽  
Author(s):  
H. Kaneko ◽  
Y. Nakanishi ◽  
S. Akagi ◽  
K. Arai ◽  
K. Taya ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Follicular Phase

298 COMPARISON OF THREE DIFFERENT PROTOCOLS FOR SUPERSTIMULATION OF DAIRY CATTLE

2009 ◽  
Vol 21 (1) ◽  
pp. 246 ◽  
Author(s):  
R. G. Steel ◽  
J. F. Hasler
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Estrous Cycle ◽  
Embryo Transfer ◽  
Animal Health ◽  
Bovine Embryo ◽  
Transfer Program ◽  
Frozen Semen ◽  
Pfizer Animal Health ◽  
Estradiol 17Β

Traditionally, successful superstimulation of cattle depended on initiating injections of gonadotrophin at mid-cycle, approximately at second follicular wave emergence. This approach limited the convenience of scheduling donors for superstimulation. With the use of intravaginal progesterone-releasing devices and estradiol 17β, superstimulation can be initiated successfully at any time of the estrous cycle. However, because estradiol cannot be legally injected into cattle in an increasing number of countries, the efficacy of GnRH as an estradiol substitute was investigated. A retrospective analysis was performed on data collected in a commercial bovine embryo transfer program over a period of several years. All donors were lactating dairy cows at least two years of age; approximately 75% were comprised of Holstein and the remainder of Jersey, Guernsey, or Brown Swiss breeds. The three treatments employed were (1) Controls injected twice daily for 4 days with a total of 240 to 400 mg of porcine FSH (Folltropin-V, Bioniche Animal Health, Inc.) in decreasing doses starting between day 7 and day 14 of diestrus, with PG (Lutalyse, Pfizer Animal Health) given at the time of FSH injections no. 5 (35 mg) and 6 (25 mg); (2) Estradiol females received a CIDR (Pfizer Animal Health), 5.0 mg estradiol 17β and 100 mg progesterone in oil on random days of the estrous cycle; FSH was initiated 4 days later as described for controls with CIDR removal at the time of FSH injection no. 6; (3) GnRH females received a CIDR on random days of the estrous cycle and 100 μg GnRH on day 1.5 following CIDR insertion; FSH was initiated 60 h after GnRH injection as described for controls with CIDR removal at the time of FSH injection no. 6. All donors were inseminated with one straw of frozen semen 12 and 24 h after the onset of estrus. Embryos were nonsurgically recovered 7 to 8 days after onset of estrus. Only embryos of grades 1 to 3 (IETS classification) were included in the data. Data were analyzed by ANOVA and Tukey’s hsd test was used to distinguish significance among means as shown in Table 1. Estradiol females produced approximately 2 more ova/embryos per procedure than Control and GnRH groups and an average of 0.8 more embryos per female than did the Control group, but there was no difference compared to the GnRH group. Similar to what has been shown in other commercial embryo transfer data sets, nearly 25% of the donors in each group failed to produce at least one good embryo. Clearly, all three treatments resulted in efficacious superstimulation. In light of the legality issues surrounding the use of estradiol, this study shows that GnRH can be used quite successfully to superstimulate dairy cattle at random times of the estrous cycle. Table 1.Average numbers of ova and embryos recovered from dairy cows superstimulated with three different protocols We thank G.E. Seidel, Jr. and S.C. Purcell for assistance with statistical analysis.

Changes in Plasma Concentrations of Inhibin, Estradiol-17β, Progesterone, LH and FSH Associated with Follicular Waves During the Estrous Cycle in Sows.

2008 ◽  
Vol 78 (Suppl_1) ◽  
pp. 103-104
Author(s):  
Michiko Noguchi ◽  
Koji Yoshioka ◽  
Chie Suzuki ◽  
Sachiko Arai ◽  
Seigo Itoh ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Plasma Concentrations ◽  
Follicular Waves ◽  
Estradiol 17Β

Effect of aglepristone (RU534) administration during follicular phase on progesterone, estradiol‐17β and LH serum concentrations in bitches

2020 ◽  
Vol 55 (12) ◽  
pp. 1794-1802
Author(s):  
Alessandro Troisi ◽  
Angela Polisca ◽  
Lucia Cardinali ◽  
Riccardo Orlandi ◽  
Gabriele Brecchia ◽  
...  
Keyword(s):  
Follicular Phase ◽  
Serum Concentrations ◽  
Estradiol 17Β

The effect of rivastigmine on the LPS-induced suppression of GnRH/LH secretion during the follicular phase of the estrous cycle in ewes

2013 ◽  
Vol 138 (3-4) ◽  
pp. 203-212 ◽  
Author(s):  
A.P. Herman ◽  
A. Krawczyńska ◽  
J. Bochenek ◽  
K. Haziak ◽  
K. Romanowicz ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Follicular Phase ◽  
Lh Secretion
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