Effects of exogenous insulin and body condition on metabolic hormones and gonadotropin-induced follicular development in prepuberal gilts

1991 ◽  
Vol 69 (5) ◽  
pp. 2081-2091 ◽  
Author(s):  
Isidro A. Matamoros ◽  
Nancy M. Cox ◽  
Alfred B. Moore
Reproduction ◽  
2010 ◽  
Vol 140 (6) ◽  
pp. 865-874 ◽  
Author(s):  
C Viñoles ◽  
B Paganoni ◽  
K M M Glover ◽  
J T B Milton ◽  
D Blache ◽  
...  

We have developed an experimental model in which groups of ewes are simultaneously experiencing the first ovarian follicular wave of their oestrous cycle. We used this ‘first-wave model’ in a 2×2 factorial experiment (ten ewes per group) to study the effect of body condition (BC) and a short-term supplement on follicular dynamics and ovulation rate. The ‘first-wave’ was established by giving ewes three injections of prostaglandin (PG), 7 days apart. The 6-day supplement (lupin grain) began 2 days after the second PG injection and continued until the third. Follicles were studied by ultrasound, and blood was sampled to measure glucose and hormones. The supplement increased (P<0.01) the concentrations of glucose, insulin and leptin, decreased FSH concentrations (P<0.01) and tended to increase oestradiol concentrations (P=0.06). The supplement tended to increase the number of 3 mm follicles (P=0.06). Compared with low-BC ewes, high-BC ewes had more follicular waves (P<0.05), higher concentrations of insulin, leptin and IGF1 (P<0.05) and tended to have higher FSH concentrations (P=0.09). Leptin and insulin concentrations remained high until the end of supplementation in high-BC ewes, whereas they decreased after the third day of supplementation in low-BC ewes. In conclusion, high concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves. When a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate.


2002 ◽  
Vol 74 (3) ◽  
pp. 539-545 ◽  
Author(s):  
C. Viñoles ◽  
L. J. Harris ◽  
M. Forsberg ◽  
G. Banchero ◽  
E. Rubianes

AbstractIn this investigation we tested the hypothesis that static body condition (BC) of the ewe affects oestradiol and FSH with implications for subsequent follicular growth and turn-over. Sixteen Polwarth ewes were selected from a flock according to their BC score (scale: 1 emaciated; 5 obese). High BC (HBC) ewes (no. = 8) had a BC score of 4·1 (s.e. 0·1) and low BC (LBC) ewes (no. = 8) had a BC score of 1·9 (s.e. 0·1). Daily ultrasound examinations were performed and blood samples for progesterone, oestradiol and follicle-stimulating hormone (FSH) determination were collected. All HBC ewes (8/8) exhibited three waves of follicular development, while four LBC ewes (4/8) had two waves and the other four (4/8) had three waves of follicular development (P ≤ 0·05) during the interovulatory period. Overall, the emergences of 33 out of 44 follicular waves were preceded by significant increases in FSH concentrations. Maximum FSH concentrations were detected 0·9 ± 0·2 days before wave emergence. Oestradiol concentrations increased significantly during the growing phase in 38 out of 44 large follicles. A negative correlation between oestradiol and FSH was observed in HBC ewes. A similar inhibitory effect of oestradiol on FSH was observed in LBC ewes, irrespective of whether they developed two or three follicular waves. However, a longer period with high FSH was needed to promote the emergence of the second follicular wave in two-wave LBC ewes. Four HBC ewes had twin ovulations but no LBC ewes did (P ≤ 0·05). In HBC ewes, the follicular phase was characterized by lower oestradiol (6·5 (s.e. 1·0) pmol/l) but higher mean FSH concentrations (2·4 (s.e.0·4) μg/l) than in LBC ewes (8·9 (s.e. 1·2) pmol/l and 2·0 (s.e. 0·3) μg/l, respectively; P ≤ 0·05). The present results suggest that BC influences the pattern of follicular dynamics through changes in the endocrine milieu. Higher FSH concentrations during the follicular phase in HBC ewes, which allowed an extended period of follicular recruitment from a significantly larger pool of small antral follicles could explain the higher ovulation rate observed in this group.


2018 ◽  
Vol 6 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Marta Rybska ◽  
Sandra Knap ◽  
Maurycy Jankowski ◽  
Michal Jeseta ◽  
Dorota Bukowska ◽  
...  

AbstractFolliculogenesis is the process of ovarian follicle formation,, taking presence during foetal period. During the follicular development, oogoniums undergo meiosis and oocytes are formed. In the ovaries of new born sows, primary and secondary follicles are present and, 90 days after birth, tertiary follicles appear. During development in the ovarian follicles growth of granulosa cells and differentiation of the thecal cells can be observed. A cavity filled with follicular fluid appears. Granulosa cells are divided into: mural cells and corona radiata, which together with the oocyte form the cumulus oophorus. Corona radiata cells, mural layers and oolemma contact each other by a network of gap junctions. Secreted from the pituitary gland, FSH and LH gonadotropin hormones act on receptors located in granular and follicular cells. In the postnatal life tertiary follicles and Graafian follicles are formed. When the follicle reaches a diameter of 1 mm, further growth depends on the secretion of gonadotropins. Mature ovarian follicles produce: progestins, androgens and oestrogens. The growth, differentiation and steroidogenic activity of ovarian follicles, in addition to FSH and LH, is also affected by prolactin, oxytocin, steroid and protein hormones, numerous proteins from the cytokine and interleukin family, metabolic hormones like insulin, glucocorticoids, leptin, thyroid hormones and growth hormones. Despite numerous studies, many processes related to folliculogenesis have not been discovered Learning the mechanisms regulating reproductive processes would allow to easily distinguish pathological processes and discover more and more genes and mechanisms of their expression in cells that build ovarian follicles.


Author(s):  
L. Pinto Andrade ◽  
S.M. Rhind ◽  
L.A. Wright ◽  
S.R. McMillen ◽  
T.K. Whyte

Previous studies have indicated that low body condition (LBC) at calving increases the duration of the postpartum anoestrous period in suckling beef cows (Henricks et al 1986; Wright et al 1987). The results of recent experiments also suggest that animals in LBC have a reduced incidence of LH pulses (Wright et al 1990) which is associated with a reduction in the incidence of large, oestrogenic, potentially ovulatory ovarian follicles (Prado et al 1990).An experiment was designed to determine a) whether or not the normal process of follicular development can be accelerated in LBC cows by infusion of pulses of GnRH, so that their postpartum anoestrous period was as short as that of cows in HBC and b) the effect of GnRH pulse infusions on associated gonadotropin profiles.


2018 ◽  
Vol 110 ◽  
pp. 142-147 ◽  
Author(s):  
A.V. Sirotkin ◽  
A.V. Makarevich ◽  
E. Kubovicova ◽  
J. Laurincik ◽  
S. Alwasel ◽  
...  

Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 299-309 ◽  
Author(s):  
C Viñoles ◽  
M Forsberg ◽  
G B Martin ◽  
C Cajarville ◽  
J Repetto ◽  
...  

This study tested whether the effects of a short period of nutritional supplementation given to ewes during the luteal phase on follicle development and ovulation rate is associated with an increase in circulating concentrations of FSH, glucose or metabolic hormones. Oestrus was synchronised with two prostaglandin injections given 9 days apart and the supplement consisted of corn grain and soybean meal. Corriedale ewes with low body condition were randomly assigned to 2 groups: the control group (C; n = 10) received a maintenance diet while the short-term supplemented group (STS; n = 10) received double the maintenance diet over days 9 to 14 of the oestrous cycle (day 0 = ovulation). Ovaries were examined daily by ultrasound and blood was sampled three times a day during the inter-ovulatory interval for measuring reproductive and metabolic hormones. On days 9, 11 and 14 of the oestrous cycle, half of the ewes from each group (n = 5) were bled intensively to determine the concentrations of glucose, insulin, IGF-I and leptin. Plasma FSH, progesterone, oestradiol and androstenedione concentrations were similar among groups. Dietary supplementation increased plasma insulin concentrations from the first to the sixth day of supplementation and increased glucose concentrations on the third day, compared with control ewes. Plasma leptin concentrations were higher in STS ewes from the second to the fifth day of supplementation. The pattern of IGF-I concentrations was similar among groups. In STS ewes, the nutritional treatment prolonged the lifespan of the last non-ovulatory follicle, so fewer follicular waves developed during the cycle. In STS ewes, increased concentrations of glucose, insulin and leptin one day before ovulatory wave emergence were associated with increased numbers of follicles growing from 2 to 3 mm and with stimulation of the dominant follicle to grow for a longer period. We suggest that the mechanism by which short-term nutritional supplementation affects follicle development does not involve an increase in FSH concentrations, but may involve responses to increased concentrations of glucose, insulin and leptin, acting directly at the ovarian level. This effect is acute, since concentrations of all three substances decrease after reaching peak values on the third day of supplementation. The status of follicle development at the time of maximum concentrations of glucose and metabolic hormones may be one of the factors that determines whether ovulation rate increases or not.


1987 ◽  
Vol 115 (1) ◽  
pp. 75-83 ◽  
Author(s):  
A. S. McNeilly ◽  
J. A. Jonassen ◽  
S. M. Rhind

Abstract. The effect of body condition on ovarian follicular development was investigated in Scottish Blackface ewes in high and low body condition. Follicles were dissected from ovaries on days 11 and 12 of the luteal phase and 24 h after prostaglandin-induced luteal regression. Ewes in low body condition had a lower ovulation rate (low: 0.9; high: 1.8 P < 0.05) and lower mean plasma levels of FSH during both the luteal (low: 54; high: 72 μg/l) and follicular (low: 34; high: 43 μg/l) phases of the cycle. Low body condition was associated with a reduced number of large (⩾ 4 mm) follicles in both the luteal and follicular phases, and in low condition a lower proportion of these follicles was oestrogenic and potentially ovulatory as assessed by follicular fluid levels of oestradiol. However, within the different oestrogenic classifications of these large follicles there were no significant differences in the steroidogenic capacity as assessed by the concentrations of either oestradiol or testosterone in follicular fluid, basal and hCG-stimulated testosterone production, thecal 125I hCG binding or basal and testosterone-stimulated oestradiol production by granulosa cells in relation to body condition. These results suggest that body condition influences ovulation rate by altering the concentration of FSH in blood, which in turn affects the number of potentially ovulatory follicles growing beyond 4 mm.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 117-117
Author(s):  
James Richard Pursley ◽  
Thaina MInela ◽  
Joao Paulo Martins ◽  
Emily Middleton

Abstract Pregnancy loss in high producing dairy cows is significant and negatively affects profitability of dairy farms. It is not clear the extent of pregnancy loss prior to a subsequent estrus or first pregnancy diagnosis. It is clear that percent of cows losing pregnancies are greatest following 1st pregnancy diagnoses then decrease in a time-related fashion throughout gestation. Non-disease related factors that are associated with pregnancy losses in dairy cows include parity, timing of AI relative to ovulation, circulating concentrations of progesterone during growth of the ovulatory follicle(s), double ovulations, unilateral twins, service sire, extent of change in body condition during early lactation, and serum levels of pregnancy associated glycoproteins at 24 or 28 d post-AI. Metabolic changes related to high milk production resulted in a greater chance for double ovulations. A growing body of literature indicates that cows with unilateral double ovulations and unilateral twins have a greater chance for pregnancy loss during the 1st 90 d of pregnancy compared to cows with single ovulations or bilateral twins. It also appears there is a preferential timing of loss in cows with double vs. single ovulations. Levels of circulating concentrations of progesterone during follicular wave development affect follicular development of cows. In a study that controlled progesterone during follicular development, low levels of progesterone caused a greater percentage of cows to have double ovulations and increased chances for pregnancy loss after 35 d post-AI. Lastly, it appears that cows that lose body condition during the 1st 30 DIM have a greater chance of pregnancy loss between 35 and 69 d post-AI compared with cows that maintained or gained body condition during that period. These data lead towards a greater understanding of the potential causes of pregnancy loss in dairy cows and can be instrumental in the development of reproductive technologies to reduce these losses.


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