Endocrinology of nutritional flushing in gilts

1991 ◽  
Vol 71 (4) ◽  
pp. 1063-1071 ◽  
Author(s):  
E. Beltranena ◽  
G. R. Foxcroft ◽  
F. X. Aherne ◽  
R. N. Kirkwood
Keyword(s):  
Plasma Insulin ◽  
Follicle Stimulating Hormone ◽  
Follicular Phase ◽  
Ovulation Rate ◽  
Feeding Level ◽  
Factor I ◽  
Igf I ◽  
Endocrine Status ◽  
Ad Libitum ◽  
Estradiol 17Β

As part of a nutritional flushing study, the endocrine status of gilts was compared to gain further knowledge of the mechanism(s) that mediate the restoration of ovulation rate. From 45.3 kg BW to puberty, 42 gilts were fed 2.0 kg d−1 (L) or ad libitum (H). From puberty to second estrus, one-half of the L gilts had their feed allowance increased to 2.8 kg d−1 (LH). Gilts in the H group continued to be fed ad libitum (HH). Gilts in the LH and H groups showed a greater increase in ovulation rate between first and second estrus than LL gilts (P < 0.05). Based on sampling every 4 h through the peri-estrous period of 28 gilts, feeding level did not affect mean plasma follicle-stimulating hormone (FSH), luteinizing hormone (pLH), estradiol-17β or progesterone concentrations (P > 0.05). During the follicular phase, however, LH and HH gilts had not only a greater proportion of samples > 1 ng mL−1 but also showed an increased mean pLH daily sample variance compared with LL gilts (P < 0.05). The latter parameters were interpreted as indicators of an increased frequency of episodic pLH release. Furthermore, HH gilts had greater (P < 0.05) plasma insulin concentrations through the peri-estrous period and greater insulin-like growth factor I (IGF-I) concentrations during the pLH-surge period than LL gilts. These results confirm that increased plasma insulin may be an important metabolic cue, which in an independent or synergistic action with gonadotropins and IGF-I mediates the ovulatory response to flush-feeding. Key words: Gilt, flushing, ovulation, gonadotropins, insulin, IGF-I.

Relationships between follicle-stimulating hormone, follicle growth and ovulation rate in sheep

1996 ◽  
Vol 8 (2) ◽  
pp. 279 ◽  
Author(s):  
RC Fry ◽  
MA Driancourt
Keyword(s):  
Follicle Stimulating Hormone ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Ovulation Rate ◽  
Follicle Growth ◽  
Group I ◽  
Group 3 ◽  
Group 2 ◽  
Group 1 ◽  
Stimulating Hormone

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.

scholarly journals Origin of Plasma Insulin-Like Growth Factor-I (IGF-I) During Estrus in Goats

2003 ◽  
Vol 49 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Sumie NONAKA ◽  
Tsutomu HASHIZUME ◽  
Mami HORIUCHI ◽  
Utako MIKAMI ◽  
Takeshi OSAWA ◽  
...  
Keyword(s):  
Growth Factor ◽  
Plasma Insulin ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Resveratrol directly affects ovarian cell sirtuin, proliferation, apoptosis, hormone release and response to follicle-stimulating hormone (FSH) and insulin-like growth factor I (IGF-I)

2019 ◽  
Vol 31 (8) ◽  
pp. 1378 ◽  
Author(s):  
Alexander Sirotkin ◽  
Richard Alexa ◽  
Attila Kádasi ◽  
Erika Adamcová ◽  
Saleh Alwasel ◽  
...  
Keyword(s):  
Growth Factor ◽  
Follicle Stimulating Hormone ◽  
Sirtuin 1 ◽  
Insulin Like Growth Factor ◽  
Ovarian Cell ◽  
Cell Functions ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Stimulating Hormone

The objective of our study was to examine the influence of the plant polyphenol resveratrol (R) on the rapamycin signalling pathway (mammalian target of rapamycin; mTOR) and basic ovarian cell functions in mammalian targets, as well as on their response to the physiological hormonal stimulators follicle-stimulating hormone (FSH) and insulin-like growth factor I (IGF-I). Resveratrol was found to stimulate sirtuin 1 accumulation and apoptosis, inhibit proliferation, suppress P and promote T and E release. Alone, FSH promoted proliferation and had no effect on apoptosis, but had an inhibitory effect on these processes when combined with R. IGF-I alone stimulated proliferation and inhibited apoptosis and promoted P production but not that of T; however, in the presence of R, the addition of IGF-I switched from having an anti-apoptotic to a pro-apoptotic effect and stimulated T release, but it did not modify the effect of IGF-I on proliferation and P output. These observations: (1) demonstrate that R directly affects the basic ovarian cell functions of proliferation, apoptosis and steroidogenesis, (2) provide further evidence of the involvement of FSH and IGF-I in the regulation of these processes, (3) demonstrate the ability of R to prevent and even invert the effects of FSH and IGF-I on ovarian cells and (4) indicate that the effects of R may be mediated by the mTOR–sirtuin intracellular signalling system.

Effect of sodium selenite on growth, insulin-like growth factor-binding proteins and insulin-like growth factor-I in rats

1995 ◽  
Vol 145 (1) ◽  
pp. 105-112 ◽  
Author(s):  
H Grønbæk ◽  
J Frystyk ◽  
H Ørskov ◽  
A Flyvbjerg
Keyword(s):  
Growth Factor ◽  
Sodium Selenite ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Selenium Treatment ◽  
Group A ◽  
Ad Libitum ◽  
Group B ◽  
Igfbp 3

Abstract Selenium is an essential trace element although at higher doses it is also known to be a toxic agent causing a wide range of symptoms including growth retardation. In order to investigate the effect of sodium selenite on growth, insulin-like growth factor-binding proteins (IGFBPs) and insulin-like growth factor-I (IGF-I), 30 male Wistar rats were randomized into three groups. Group A was treated with sodium selenite in the drinking water (3·3 mg selenium/l). Group B was ad libitum fed with free access to standard fodder and tap water and group C was pair fed relative to the selenium-treated rats. Serum IGF-I and IGFBPs were determined on days 0, 14 and at the end of the study on day 35. Selenium-treated rats had significantly lower body weights compared with group B rats on day 9 and group C rats on day 14 (P<0·05). Tibia length was measured at the end of the study and no difference was observed between groups B and C (3·77 ± 0·04 cm vs 3·60±0·02 cm); however, selenium-treated rats had significantly shorter tibia lengths (3·46±0·03 cm) compared with rats in groups B (P<0·001) and C (P<0·05). Selenium treatment induced a significant reduction in circulating IGF-I by the end of the study compared with ad libitum and pair fed rats (P<0·05). Serum subjected to Western ligand blots showed four distinct IGFBP bands with apparent relative molecular weights of 38–47 kDa (doublet) (IGFBP-3), 30 kDa (IGFBP-1 and/or IGFBP-2) and 24 kDa (IGFBP-4). At the end of the study a significant reduction in IGFBP-3 was observed in group A compared with groups B and C (P<0·05). Selenium treatment also caused a reduction in IGFBP-1 and/or IGFBP-2 compared with ad libitum fed rats; in addition, a reduction was observed in pair fed controls. In conclusion, sodium selenite treatment leads to growth retardation accompanied by reduced circulating levels of IGF-I, IGFBP-3, and IGFBP-1 and/or IGFBP-2. The reduction in IGF-I and IGFBP-3 could not be attributed to reduced caloric intake but seems to be a specific action of selenium. Journal of Endocrinology (1995) 145, 105–112

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