Selection of fewer dominant follicles in Trio carriers given GnRH antagonist and luteinizing hormone action replaced by nonpulsatile human chorionic gonadotropin†

2020 ◽  
Vol 103 (6) ◽  
pp. 1217-1228
Author(s):  
Victor E Gomez-León ◽  
João Paulo Andrade ◽  
Brian W Kirkpatrick ◽  
Sadrollah Molaei Moghbeli ◽  
Alvaro García-Guerra ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Gnrh Antagonist ◽  
Maximum Diameter ◽  
High Fecundity ◽  
Follicle Diameter ◽  
Follicle Selection ◽  
Selection Of

Abstract Studying selection of multiple dominant follicles (DFs) in monovulatory species can advance our understanding of mechanisms regulating selection of single or multiple DFs. Carriers of the bovine high fecundity Trio allele select multiple DFs, whereas half-sib noncarriers select a single DF. This study compared follicle selection during endogenous gonadotropin pulses versus during ablation of pulses with Acyline (GnRH antagonist) and luteinizing hormone (LH) action replaced with nonpulsatile human chorionic gonadotropin (hCG) treatment in Trio carriers (n = 28) versus noncarriers (n = 32). On Day 1.5 (Day 0 = ovulation), heifers were randomized: (1) Control, untreated; (2) Acyline, two i.m. doses (Days 1.5 and D3) of 3 μg/kg; (3) hCG, single i.m. dose of 50 IU hCG on Day 1.5 followed by daily doses of 100 IU; and (4) Acyline + hCG. Treatments with nonpulsatile hCG were designed to replace LH action in heifers treated with Acyline. Acyline treatment resulted in cessation of follicle growth on Day 3 with smaller (P < 0.0001) maximum follicle diameter in Trio carriers (6.6 ± 0.2 mm) than noncarriers (8.7 ± 0.4 mm). Replacement of LH action (hCG) reestablished follicle diameter deviation and maximum diameter of DFs in both genotypes (8.9 ± 0.3 mm and 13.1 ± 0.5 mm; P < 0.0001). Circulating follicle stimulating hormone (FSH) was greater in Acyline-treated than in controls. Finally, Acyline + hCG decreased (P < 0.0001) the number of DFs from 2.7 ± 0.2 to 1.3 ± 0.2 in Trio carriers, with most heifers having only one DF. This demonstrates the necessity for LH in acquisition of dominance in Trio carriers (~6.5 mm) and noncarriers (~8.5 mm) and provides evidence for a role of GnRH-induced FSH/LH pulses in selection of multiple DFs in Trio carriers and possibly other physiologic situations with increased ovulation rate.

129 Ovarian dynamics and gonadotropins during selection of the dominant follicle in postpartum lactating versus non-postpartum cycling mares

2020 ◽  
Vol 32 (2) ◽  
pp. 191
Author(s):  
M. Pastorello ◽  
M. O. Gastal ◽  
G. K. Piquini ◽  
D. B. Godoi ◽  
E. L. Gastal
Keyword(s):  
Growth Rate ◽  
Maximum Diameter ◽  
Sequential Data ◽  
Dominant Follicle ◽  
Follicle Diameter ◽  
The Mean ◽  
Low Levels ◽  
Follicle Selection ◽  
Ovarian Dynamics ◽  
Selection Of

The mare, compared to other livestock, has the shortest interval from partum to the first ovulation. In monovulatory species, the follicle deviation process in a wave is characterised by the continued growth of the dominant follicle (DF) and regression of the subordinate follicle. Although follicle diameter deviation, a key event of follicle selection, has been investigated during the oestrous and menstrual cycles, the occurrence of this phenomenon before the first postpartum ovulation seems to be unclear in all species. This study aimed to compare the follicular dynamics and gonadotropin profiles around the follicle diameter deviation day in postpartum lactating (PP Lactating; n=24) versus non-postpartum cycling (NPP Cycling; n=15) mares. On the day of parturition, every PP Lactating mare was paired with an NPP Cycling mare, and ovarian follicles (>4mm) were tracked daily by transrectal ultrasonography, and blood samples were collected. Data were analysed in the PP Lactating group according to the length of the partum-ovulation interval (POI; ≤22 and >22 days) and the postpartum interovulatory interval (PPIOI), and in the NPP Cycling group during two interovulatory intervals (1st and 2nd IOI). In addition, regardless of group, all four intervals were compared. We performed the FSH and LH assays using radioimmunoassay. Ovarian and hormonal parameters were analysed using ANOVA for sequential data. The day and diameter of the DF at the deviation (overall mean: 14.9±2.5 days; 21.7±0.4mm, respectively) were not different (P>0.05) between PP Lactating and NPP Cycling mares. However, when considering the length of POI, follicle deviation occurred 4.4±0.8 days earlier (P<0.001) in mares with POI ≤ 22 days than in mares with POI>22 days. No difference was found between PP Lactating and NPP Cycling mares within and between groups for the intervals from deviation to maximum diameter of the DF (10.4±0.4 days), for the intervals from deviation to ovulation (12.1±0.5 days), or for the growth rates of the DF from deviation to maximum diameter (2.6±0.1mm per day). The growth rate of the DF from deviation to ovulation (2.4±0.1mm per day) did not differ between PP Lactating and NNP Cycling mares; however, this growth rate was lower (P<0.03) in the POI, PPIOI, and 1st IOI compared with the 2nd IOI. The mean diameter of the DF around deviation (days −3 to 3; 22.5±0.3mm), and systemic FSH (days −4 to 4; 10.3±0.2ngmL−1) were not different between PP Lactating and NPP Cycling mares. Level of LH was lower (P<0.0001) around deviation (days −4 to 4) in the PP Lactating (0.7±0.0ngmL−1) versus the NPP Cycling mares (1.8±0.1ngmL−1). Results demonstrated that a partum effect occurs only on the day of deviation in mares during the foal heat (POI ≤ 22 days) and that low levels of LH during both intervals in PP Lactating mares were not detrimental to prevent ovulation.

Role of luteinizing hormone in luteotropic complex of pregnant hamster

1987 ◽  
Vol 252 (4) ◽  
pp. E500-E504 ◽  
Author(s):  
H. Tamura ◽  
G. S. Greenwald
Keyword(s):  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Vaginal Smear ◽  
Serum Progesterone ◽  
Luteal Function ◽  
Antral Follicles ◽  
Rate Of Absorption ◽  
Long Acting

Hamsters were hypophysectomized on day 4 of pregnancy (day 1 = sperm in vaginal smear) and injected subcutaneously on days 4-7 with various combinations of 200 micrograms prolactin (Prl), 10 micrograms follicle-stimulating hormone (FSH), and 20 micrograms luteinizing hormone (LH) in polyvinylpyrrolidone (PVP) to decrease its rate of absorption or in saline. End points for luteal function on day 8 were maintenance of pregnancy, serum progesterone (P4), luteal weight, and luteal binding for human chorionic gonadotropin, FSH, and Prl. After hypophysectomy, a drastic decline occurred in all parameters including an 89% decrease in luteal weight. Injection of Prl did not maintain pregnancy nor serum P4 but partially maintained luteal weight and human chorionic gonadotropin binding sites per corpus luteum. The minimal luteotropic complex of Prl and FSH was effective in maintaining pregnancy and significantly increased serum P4 and Prl and FSH receptors but not to control levels; Prl and LH (PVP) was also effective to the same extent. Antral follicles were lacking after either treatment. The effects of FSH cannot be attributed to LH contamination. All variables were restored to control levels by Prl plus FSH plus LH (PVP) and antral follicles were present; Prl plus FSH plus LH (saline), however, induced luteolysis and reduced most values to the levels found in untreated, hypophysectomized animals. Thus, the luteotropic activity of LH was only demonstrable when it was injected in a long-acting form; when delivered as a bolus, LH (saline) was luteolytic.

scholarly journals Necessity for LH in selection and continued growth of the bovine dominant follicle

Reproduction ◽  
2020 ◽  
Vol 159 (5) ◽  
pp. 559-569 ◽  
Author(s):  
Victor E Gomez-León ◽  
O J Ginther ◽  
Rafael R Domingues ◽  
José D Guimarães ◽  
Milo C Wiltbank
Keyword(s):  
Chorionic Gonadotropin ◽  
Acute Treatment ◽  
Gnrh Antagonist ◽  
Underlying Mechanism ◽  
Dominant Follicle ◽  
Follicle Growth ◽  
Follicular Wave ◽  
Treatment Data ◽  
Follicle Selection ◽  
Selection Of

Previous research demonstrated that acute treatment with GnRH antagonist, Acyline, allowed follicle growth until ~8.5 mm and no dominant follicle was selected. This study evaluated whether deficient LH was the underlying mechanism for Acyline effects by replacing LH action, using human chorionic gonadotropin (hCG), during Acyline treatment. Holstein heifers (n = 24) during first follicular wave were evaluated by ultrasound and randomized into one of three treatments: Control (saline treatments), Acyline (5 µg/kg Acyline), or Acyline+hCG (Acyline plus 50 IU of hCG at start then 100 IU every 12 h). Pulses of LH were present in Control heifers (9 Pulses/10 h) but not during Acyline treatment. Data were normalized to the transition to diameter deviation (day 0; F1 ~7.5 mm). Diameter deviation of the largest (F1) and the second largest (F2) follicle was not observed in Acyline-treated heifers, whereas control heifers had decreased growth of F2 at F1 ~7.5 mm, indicating deviation. Selection of a single dominant follicle was restored by providing LH activity in Acyline+hCG heifers, as evidenced by F1 and F2 deviation, continued growth of F1, and elevated circulating estradiol. Separation of F1 and F2 occurred 12 h (~7.0 mm) earlier in Acyline+hCG heifers than Controls. Circulating FSH was greater in Acyline than Controls, but lower in Acyline+hCG than Controls after day 1.5. In conclusion, dominant follicle selection and growth after follicle deviation is due to LH action as shown by inhibition of this process during ablation of GnRH-stimulated LH pulses with Acyline and restoration of it after replacement of LH action by hCG treatment.

Role of thyroid hormone in controlling the concentration of luteinizing hormone/human chorionic gonadotropin receptors in rat ovaries

1994 ◽  
Vol 130 (4) ◽  
pp. 378-380 ◽  
Author(s):  
Remigiusz Fitko ◽  
Beata Szlezyngier
Keyword(s):  
Thyroid Hormone ◽  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Ovarian Function ◽  
Polycystic Ovary ◽  
Ovary Syndrome ◽  
Gonadotropin Receptors ◽  
Receptor Concentration

Fitko R, Szlezyngier B. Role of thyroid hormone in controlling the concentration of luteinizing hormone/human chorionic gonadotropin receptors in rat ovaries. Eur J Endocrinol 1994;130:378-80. ISSN 0804–4643 Little is known about the mechanism by which thyroid hormones influence ovarian function, especially in gonadotropin receptor formation. In this study the concentration of Iuteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptors in the ovaries of hypo- and hyperthyroid rats was estimated. Rats were made experimentally hypothyroid by thyroidectomy (N = 10) and hyperthyroid by injections of 40 μg of l-thyroxine daily for 21 days (N = 14). After 3 weeks the ovaries were excised, weighed, immersed in liquid nitrogen and then, after 24 h of incubation with 125I-labeled hCG (CR-121), the concentration of receptors (cpm) for one ovary and 1 mg of tissue was counted in their respective homogenates. The ovaries of the hyperthyroid group were diminished in size and consequently the level of receptors per ovary also was reduced when compared with control animals. The number of receptors per ovary and per milligram of tissue of hypothyroid rats was three times higher than in the control. In hyperthyroid animals a significant decrease in these values was noted when compared with hypothyroid rats, especially in the calculation of receptor concentration per ovary. It may be concluded that thyroid function may affect the size of the gland and also the number of LH/hCG-binding sites in rat ovaries. These data may be useful for interpretation of the pathophysiology of polycystic ovary syndrome in women and animals. R Fitko, Department of Experimental Pathology, Centre for Agrotechnology and Veterinary Sciences, 10-718 Olsztyn, ul. Prawocheñskiego 5, Poland

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