THE RELATION BETWEEN NATURAL FECUNDITY AND RESPONSE TO FOLLICLE-STIMULATING HORMONE

1962 ◽  
Vol 25 (1) ◽  
pp. 137-144 ◽  
Author(s):  
ANNE McLAREN

SUMMARY A study was made of the response to induced ovulation of female mice from strains in which the spontaneous ovulation rate had increased as a result of artificial selection for litter size. In response to standard doses of follicle-stimulating hormone (FSH) within the physiological range, the number of eggs shed differed significantly among the three strains tested, in the direction expected on the basis of their spontaneous ovulation rates. This indicates that the principal effect of selection has been to increase the sensitivity of the ovary to FSH. In one strain, the possibility remains open that there may also have been some increase in the amount of FSH available. In response to larger doses of FSH, females from the strain with the highest spontaneous ovulation rate shed significantly fewer eggs than the other two groups. Selection must therefore have altered the shape of the dose-response curve, increasing the ovarian response at low levels of hormone and decreasing it at high levels.

1991 ◽  
Vol 3 (5) ◽  
pp. 551 ◽  
Author(s):  
JP Ryan ◽  
JR Hunton ◽  
WM Maxwell

In a factorially designed experiment (N = 321), 0, 800 or 1600 I.U. pregnant mare serum gonadotrophin (PMSG) were administered in combination with 0, 12 or 18 mg follicle stimulating hormone (FSH-P) to superovulate Merino ewes in autumn and spring. A moderate dose of PMSG (800 I.U.) in conjunction with 12 or 18 mg FSH-P increased the ovulation rate above that observed when FSH-P was used alone. This was accomplished by (i) increasing the proportion of ewes that exhibited a superovulatory response (greater than 3 corpora lutea (CL) or persistent large follicles (LF): 69/70 (99%) v. 55/74 (74%), P less than 0.001), and (ii) in those ewes that exhibited a superovulatory response, by an additive effect of exogenous gonadotrophin (14.8 +/- 0.9 CL (69) v. 11.3 +/- 0.9 CL (55), P less than 0.01) without increasing the incidence of LF. The use of 1600 I.U. PMSG in conjunction with 12 or 18 mg FSH-P was characterized by an increase in the number of LF and, in comparison with 800 I.U. PMSG, a reduction in ovulation rate. Season had no effect on the numbers of CL, but total ovarian response (CL + LF) was higher in autumn than in spring (P less than 0.01), because of a greater incidence of LF (P less than 0.001). The proportion of ewes with regressed CL was higher in autumn than in spring (53/143 (37%) v. 32/156 (21%), P less than 0.01), and increased with increased dose of gonadotrophin. Furthermore, a nutritional component to the incidence of ewes with regressed CL was suggested by the observation that the mean concentration of plasma glucose was higher for ewes with normal CL than for ewes with regressed CL (P less than 0.05). Rates of ova or embryo recovery, fertilization and embryo development generally declined with an increase in the incidence of LF as a result of increases in the dose of gonadotrophin and season of administration.


1996 ◽  
Vol 8 (2) ◽  
pp. 279 ◽  
Author(s):  
RC Fry ◽  
MA Driancourt

The changes in follicle-stimulating hormone (FSH) concentration required to affect follicle growth and ovulation rate within individual ewes were examined. Relationships between peripheral FSH concentrations during the late-luteal and follicular phase and subsequent ovulation rates were investigated in 22 ewes from 4 breeds over 3 successive cycles (Experiment 1). Ewes were grouped as follows: Group 1 (n = 6), ewes exhibiting the same ovulation rate at each oestrous cycle: Group 2 (n = 5), ewes with three different ovulation rates at each oestrous cycle; and Group 3 (n = 11), ewes with the same ovulation rate at two oestrous cycles and a different ovulation rate on one occasion. Data from ewes in Group 1 and 3 provided estimates on the variation in FSH concentrations between cycles which were not large enough to alter ovulation rate (range, 0-67% variation in FSH concentration). In Group-2 ewes, there was no consistent association between increases in ovulation rate and the proportional increases in FSH concentrations. Differences in FSH concentrations were often less than those that did not alter ovulation rate in Group-I ewes. Furthermore, only 3 of 11 Group-3 ewes demonstrated high FSH concentrations associated with high ovulation rate (or low FSH concentrations and low ovulation rate) when compared with the concentrations found at the two cycles in which ovulation rate was similar. Hence, there was little evidence that FSH concentrations during the late-luteal and follicular phase are associated with changes in ovulation rate within individual ewes. In Experiment 2, follicles of similar size obtained from the same ewe (FecBFec+ and Romanov) showed markedly different responses in vitro to graded doses of FSH as measured by aromatase activity. It is concluded that, within a ewe, the large variability between gonadotrophin-dependent follicles in their requirement for FSH prevented the expression of any thresholds of ovarian response to FSH.


2020 ◽  
Author(s):  
Yujia Ma ◽  
Bo Sun ◽  
Linli Hu ◽  
Fang Wang ◽  
Ying-Pu Sun

Abstract Background: Although serum basal follicle stimulating hormone (FSH) is widely used to evaluate the ovarian response, the necessity of levels of serum FSH during the controlled ovarian hyperstimulation (COH) is controversy. When the ovarian response to COH is suboptimal due to the insufficient dose of FSH, which is often adjusted in subsequent treatment accordingly, we could detect serum FSH levels and considering that exogenous FSH is inadequate to optimal FSH threshold. We, therefore, aim to evaluate the association between the ovarian response and the difference value of serum FSH concentration in the first five days of ovarian stimulation. Methods: In this retrospective single-center study, patients were enrolled for first IVF/ICSI during the period from August 2015 to December 2017. The COH only included gonadotrophin-releasing hormone agonist (GnRH-a) protocols in which endogenous serum FSH values were suppressed, and stimulated with 150IU fixed-dose recombinant FSH (rFSH) during the first five days. Patients met all inclusion criteria were selected: age ≤ 40 years, body mass index (BMI) ≤ 32 kg/m2, regular menstruation cycle of 21-35 days and non-ovarian factor infertility. Groups were divided by the amount of oocytes collection as follows: (A) poor responders (n=27), (B) normal responders (n=638), (C) hyper responders (n=205). A multivariable logistic regression model was performed to evaluate the relationship between the ovarian response and difference value of serum FSH levels during the first five days of ovarian stimulation.Result(s): The difference value of serum FSH level (ΔFSH) between the sixth day and the first day during ovarian stimulation was measured as the primary outcome. Mean serum ΔFSH levels between groups B and C were 7.45 and 6.87, which had significant differences (p=0.0259). ΔFSH was stratified in quartiles as below: (a) ΔFSH≤5.16, (b) ΔFSH 5.16-7.11, (c) 7.11-9.09, (d) ΔFSH˃9.09. After adjusted by potential confounding factors, there was no relationship exists between ΔFSH levels and ovarian response.Conclusion(s): There is no relevance between the ovarian response and ΔFSH in the 150 IU fixed dose rFSH treatment protocol during COH. Serum FSH might not be used as an effective predictor for ovarian response and reproduction potential in IVF/ICSI clinical practice.


Author(s):  
Ilpo Huhtaniemi

The testis has two functions, androgen production and spermatogenesis, and a key role in their regulation is played by the two pituitary gonadotropins, luteinizing hormone and follicle-stimulating hormone (FSH). Other hormones and growth factors also influence testicular function, often by modulating the gonadotropin effects. Moreover, a plethora of local paracrine and autocrine signals within the testis are known. The main testicular hormone, testosterone, a Leydig cell product, regulates spermatogenesis in seminiferous tubules in paracrine fashion. The other functions of testosterone are endocrine, occurring outside the testis. This chapter summarizes the main hormonal regulatory system of the testis, the hypothalamic–pituitary–testicular axis, and how its effects are modulated by other extratesticular hormones and local testicular factors.


2010 ◽  
Vol 22 (1) ◽  
pp. 360
Author(s):  
M. I. Cueto ◽  
F. Pereyra-Bonnet ◽  
P. Silvestre ◽  
A. E. Gibbons

The aim of the study was to assess possible variations in superovulatory yields due to different FSH treatments at 2 times of the year. Superovulation and embryo recovery were performed during the breeding (n = 63) andnonbreeding (n = 46) seasons in Merino ewes located at 41°S latitude. Animals were kept under the same conditions, housed outdoors in a sheltered and covered pen, and were fed a liveweight maintenance ration. All animals received 60-mg medroxyprogesterone acetate intravaginal sponges (Progespon®, Syntex, Buenos Aires, Argentina) for 14 days. Ewes were then randomly assigned to 2 different superovulatory treatments: classic (n = 74) and one shot (n = 35) in both seasons. Classic superovulatory treatment consisted of 7 decreasing doses (2 × 48 mg, 2 × 24 mg, 2 × 20 mg, and1 × 16 mg NIH-FSH-P1)ofFSH (Folltropin®-V, Bioniche, Belleville, Ontario, Canada), administered twice daily from 48 h before to 24 h after pessary removal. A dose of eCG (300 IU; Novormon®, Syntex) was administered at progestagen removal. One shot superovulatory treatment consisted of a single dose of FSH (70 mg NIH-FSH-P1) plus 300 UI of eCG injected at pessary withdrawal. Embryo donors were inseminated by laparoscopy with frozen-thawed semen (100 × 106 spz) 12 h after the onset of estrus. Surgical embryo recovery was done on Day 7 after sponge withdrawal and embryos were graded for quality according to morphology (Grade 1 = excellent or good; Grade 2 = fair; Grade 3 = poor; and Grade 4 = dead or degenerated; IETS 1998). A 2 × 2 factorial ANOVA was used to test the main effects (season and superovulatory treatment) and interactions. There were no significant differences in the proportion of responding ewes (>3 corpora lutea), ovulation rate, and recovered Grades 1 to 2 embryos between the breeding and nonbreeding season (Table 1; P > 0.05). However, number of recovered ova/embryos and ova/embryo recovery rate were higher during the breeding season compared with the nonbreeding season, whereas the percentage of nonfertilized ova was lower in the breeding season than in the nonbreeding season (P < 0.05). Analysis of data comparing superovulatory treatments showed that the proportion of responding ewes, ovulation rate, recovered embryos, and recovered Grades 1 to 2 embryos were lower for the one shot treatment than for the classic treatment (P < 0.05). Embryo recovery rate and nonfertilization rate did not differ between treatments (P > 0.05). It was concluded that there was an increase in the number of total recovered ova/embryos during the breeding season compared with the nonbreeding season, although the number of recovered good-quality embryos was not affected. The use of multiple FSH injections produced a higher number of total recovered and viable embryos in Merino sheep than the one shot superovulatory treatment. Table 1.Embryo yields in ewes submitted to superovulation


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