scholarly journals Plasma LH and FSH in Ewes That Were Either Fertile or Infertile After Long-Term Grazing of Oestrogenic Pasture

1980 ◽  
Vol 33 (2) ◽  
pp. 213 ◽  
Author(s):  
RJ Rodgers ◽  
IJ Clarke ◽  
JK Findlay ◽  
Ainslie Brown ◽  
IA Cumming ◽  
...  
Keyword(s):  
Breeding Season ◽  
Area Under The Curve ◽  
Ovarian Vein ◽  
Blood Samples ◽  
Serial Blood ◽  
Area Unit ◽  
And Control ◽  
Lh Secretion

The levels of plasma LH and FSH were measured in serial blood samples taken at 15-min intervals for 6 h from ewes that had remained fertile after grazing oestrogenic pasture (clover-fertile ewes), from ewes that were permanently affected by clover disease (clover-infertile ewes) and from normal ewes. Two flocks of ewes from different locations were studied. In flock I, tonic LH secretion (total area under the curve of LH concentration versus time, 1 area unit = 1 ng ml- 1 x 1 h) was significantly (P < 0'05) greater in clover-infertile ewes (10'4 area units) during anoestrus than in ewes that had remained fertile after prolonged grazing of oestrogenic clover (5·4 area units). Tonic LH and FSH secretions during the breeding season and FSH secretion during anoestrus were not significantly different. In flock 2, LH levels during the breeding season were significantly (P < 0'05) elevated in clover-infertile ewes (10' 9 area units) compared to normal ewes (5' 4 area units) that had never grazed oestrogenic clover. LH secretion in clover-infertile ewes (7. 8 area units) was intermediate to that found in infertile and control ewes. Concentrations of FSH, progesterone and ovarian vein oestradiol-17 P (Ez) during the breeding season were similar in the three groups.

scholarly journals Consumption of Cross-Linked Resistant Starch (RS4XL) on Glucose and Insulin Responses in Humans

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Enas K. Al-Tamimi ◽  
Paul A. Seib ◽  
Brian S. Snyder ◽  
Mark D. Haub
Keyword(s):  
Dietary Fiber ◽  
Resistant Starch ◽  
Area Under The Curve ◽  
Postprandial Glucose ◽  
Wheat Starch ◽  
Blood Samples ◽  
Serial Blood ◽  
Insulin Levels ◽  
Insulin Responses ◽  
First Time

Objective. The objective was to compare the postprandial glycemic and insulinemic responses to nutrition bars containing either cross-linked RS type 4 (RS4XL) or standard wheat starch in normoglycemic adults (n= 13; age = 27±5 years; BMI = 25±3 kg/m2).Methods. Volunteers completed three trials during which they consumed a glucose beverage (GLU), a puffed wheat control bar (PWB), and a bar containing cross-linked RS4 (RS4XL) matched for available carbohydrate content. Serial blood samples were collected over two hours and glucose and insulin concentrations were determined and the incremental area under the curve (iAUC) was calculated.Results. TheRS4XLpeak glucose and insulin concentrations were lower than the GLU and PWB (P<.05). The iAUC for glucose and insulin were lower following ingestion of RS4 compared with the GLU and PWB trials.Conclusions. These data illustrate, for the first time, that directly substituting standard starch withRS4XL, while matched for available carbohydrates, attenuated postprandial glucose and insulin levels in humans. It remains to be determined whether this response was due to the dietary fiber and/or resistant starch aspects of theRS4XLbar.

276. Sex difference in the effect of cortisol on the LH response of the pituitary to exogenous GnRH in hypothalamo-pituitary disconnected gonadectomised sheep

2005 ◽  
Vol 17 (9) ◽  
pp. 114
Author(s):  
C. A. Stackpole ◽  
I. J. Clarke ◽  
A. I. Turner ◽  
A. J. Tilbrook
Keyword(s):  
Sex Difference ◽  
Breeding Season ◽  
Sex Steroids ◽  
Present Experiment ◽  
Control Period ◽  
Plasma Concentrations ◽  
Saline Infusion ◽  
Sheep Model ◽  
Blood Samples ◽  
Lh Secretion

We have used the hypothalamo-pituitary disconnected (HPD) sheep model to investigate direct pituitary actions of cortisol to suppress LH secretion in response to exogenous GnRH. We previously observed that, during the non-breeding season, treatment with cortisol did not suppress the LH response to GnRH in HPD gonadectomised rams or ewes.1 In the present experiment, we tested the effect of cortisol on the LH response to exogenous GnRH in gonadectomised HPD sheep during the breeding season. Using a cross-over design, HPD gonadectomised Romney Marsh rams (n = 6) and ewes (n = 5) received a saline or cortisol (250 μg/kg/h) infusion for 30 h on each of two days, one week apart. All animals were treated with 125 ng i.v. injections of GnRH every 2 h during a 6h control period preceding the infusion and during the infusion. Jugular blood samples were taken during the control period and the first 6 h and last 6 h of the infusion (over 3 LH pulses). Mean plasma concentrations of LH and LH pulse amplitudes, driven by programmed GnRH injections, were similar in gonadectomised rams and ewes and there were no significant effects of saline infusion between the control periods or the saline infusion in either sex. The amplitude of LH pulses was significantly (P < 0.05) reduced in rams during the first 6 h of the cortisol infusion compared to the control period, but there were no effects of the cortisol infusion in ewes. These data show that, in the absence of sex steroids, there is a sex difference in the mechanism by which cortisol acts at the pituitary to reduce LH secretion in response to exogenous GnRH in HPD gonadectomized sheep during the breeding season. We conclude that the effect of cortisol to reduce secretion of LH involves an action on the pituitary, at least in gonadectomised rams. (1)Stackpole CA, Turner AI, Clarke IJ and Tilbrook AJ (2003) Biology of Reproduction 36(Supplement 1), 288.

Effects of bovine follicular fluid on the secretion of LH and FSH in inhibin-immunized seasonally anoestrous ewes

1991 ◽  
Vol 128 (3) ◽  
pp. 403-410 ◽  
Author(s):  
P. G. Knight ◽  
J. H. M. Wrathall ◽  
R. G. Glencross ◽  
B. J. McLeod
Keyword(s):  
Follicular Fluid ◽  
Synthetic Peptide ◽  
Pulse Frequency ◽  
Α Subunit ◽  
Blood Samples ◽  
Gonadotrophin Secretion ◽  
Gonadotrophin Releasing Hormone ◽  
And Control ◽  
Lh Secretion ◽  
Dose Dependent

ABSTRACT It has been shown previously that treatment of seasonally anoestrous ewes with steroid-free bovine follicular fluid (FF), a crude inhibin-containing preparation, leads to a decrease in plasma FSH level which is accompanied by a marked increase in pulsatile LH secretion. Since FF contains several factors (e.g. activin, follistatin, unidentified components) other than inhibin, which might act to modify gonadotrophin secretion, it was of interest to establish whether these concurrent effects of FF on FSH and LH secretion persisted in ewes which had been actively immunized against a synthetic peptide replica of the α subunit of bovine inhibin. In June 1989 (anoestrous period) groups of inhibin-immune and control ewes (n = 5 per group) received 6-hourly s.c. injections of either bovine serum (2 ml) or one of two doses of FF (0·5 ml or 2 ml) for 3 days. Blood was withdrawn at 6-h intervals for 6 days beginning 24 h before the first injection. On the final day of treatment, additional blood samples were withdrawn at 15-min intervals for 8 h to monitor pulsatile LH secretion. Ewes were then challenged with exogenous gonadotrophin-releasing hormone (GnRH; 2 μg i.v. bolus) to assess pituitary responsiveness. In control ewes, FF promoted a dose-dependent suppression of basal (maximum suppression 65%; P < 0·01) and post-GnRH (maximum suppression 72%; P < 0·01) levels of FSH in plasma. This was accompanied by an increase (P < 0·01) in LH pulse frequency from 1·40±0·24 (s.e.m.) to 3·20±0·37 pulses/8 h. In contrast, FF did not affect secretion of either FSH or LH in inhibin-immunized ewes. However, mean plasma LH levels in immunized ewes were significantly lower (43%; P < 0·02) than in control ewes, irrespective of treatment. These findings indicate that in the anoestrous ewe the ability of FF to suppress plasma FSH is due entirely to its content of inhibin, that FF-induced enhancement of pulsatile LH secretion is mediated by inhibin, rather than some additional component of FF, and that immunoneutralization of endogenous inhibin can reduce LH secretion. Journal of Endocrinology (1991) 128, 403–410

Iron 59 incorporation into erythrocytes of hamsters after irradiation

1961 ◽  
Vol 201 (6) ◽  
pp. 1134-1136 ◽  
Author(s):  
W. Lohmann ◽  
J. L. Glasgow ◽  
W. H. Perkins
Keyword(s):  
Progressive Increase ◽  
Incorporation Rate ◽  
Whole Body ◽  
Blood Samples ◽  
Serial Blood ◽  
X Irradiation ◽  
Leukocyte Counts ◽  
And Control

The effect of 800 r of whole-body Co60-γ- and X-irradiation on the incorporation of citrate-Fe59 into erythrocytes of male hamsters was investigated. Iron 59 was given intraperitoneally immediately postirradition, and serial blood samples were obtained. The nonirradiated control animals showed a progressive increase in the Fe59 activity of the erythrocytes, reaching a maximum in 4–5 days. After a 5-day plateau, the activity gradually decreased. The Fe59 activity of the irradiated animals decreased, initially, then increased gradually. After 7 days the incorporation rate of Fe59 was 27% by the X-irradiated and 22% by the Co60-γ-irradiated animals, using the controls as 100% values. Ten days later the incorporation rate was 40% by the X-irradiated animals. None of the Co60-γ-irradiated animals survived 10 days, but all of the X-irradiated animals survived. In the X-irradiated animals, the leukocyte counts rose, initially, then decreased and returned, gradually, to preirradiation levels after 30 days. The specific Fe59 activity of different organs of irradiated and control hamsters is reported.

scholarly journals The Effects of Ram Exposure, Progestogen and eCG on Reproductive Performance of Fat Tail Ewes in Non-Breeding Season

2021 ◽  
Author(s):  
Massoud - Talebkhan Garoussi ◽  
Omid Mavadati ◽  
Mohammad Ali Bahonar ◽  
Mehran Dabiri
Keyword(s):  
Breeding Season ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Control Group ◽  
Control Groups ◽  
Transabdominal Ultrasonography ◽  
Fat Tail ◽  
Equine Chorionic Gonadotropin ◽  
And Control ◽  
Lh Secretion

Abstract Sheep are considered short-day breeders. Exposure of rams to anestrus ewes results in an increase in LH secretion. The aims of this study was to determine whether the presence and exposure of rams can effect on reproductive performance such as: pregnancy rate, litter size, sex of lamb, fecundity rate and prolificacy rate of fat tail Iranian Shaal breed ewes in non-breeding season using progesterone (p4) analogue with or without equine chorionic gonadotropin (eCG). Totally, 100 ewes out of 138 non-cyclic ewes with <0.5ng/ml P4 were selected for this study. They were aged 2 to >7 years old. They were stratified to two groups (control and treatment). The ewes in treatment and control groups received 13 days a sponge containing 60 mg medroxyprogesterone acetate (MPA). The treatment group consists of 3 subgroups and each group contains 25 ewes equally. They were included: 1- P4, eCG and Ram exposure. 2- P4 and ram exposure. 3- P4 and eCG. Ewes in control group received only P4. The ewes were located in isolated corrals for 40 days. The ram to ewe ratio was 1 to 5. Twenty healthy rams were housed in an isolated pen from ewes with distance 1500 m during 40 days. Rams exposed three days before sponge withdraw (day 10). They were separated by considerable distance (2 meters) using fence. The related groups received 500 IU eCG on the day of sponge removal (day 13). The rams were released into the ewe flock after removing the sponge in treatment and control groups. Pregnancy diagnosis performed using transabdominal ultrasonography. The obtained data analyzed using SPSS version 16. The conception rate in treatment and control groups were differed significantly (P<0.01). The conception rate in P4+ram exposure+ eCG, P4+ramexposure and P4+ eCG were 96%(no.24), 80%(no.20) and 88%(no.22), respectively. However, the conception rate in control group was 60% (no. 15). The fecundity rates were 136%, 100% and 124% in treatment subgroups, however, it was 84% in control group, respectively. There were no significant differences among genus and weight of lambs in treatments subgroups and control group (P>0.05). It is concluded that ram exposure can increase significantly reproductive performance in non-breeding season fat tailed ewes Shaal breed.

The induction of pregnancy in the anoestrous ewe by hormonal therapy I. Progesterone-pregnant mare's serum therapy during the breeding season

1963 ◽  
Vol 60 (1) ◽  
pp. 31-41 ◽  
Author(s):  
I. Gordon
Keyword(s):  
Breeding Season ◽  
Hormone Treatment ◽  
Limiting Factor ◽  
Normal Expression ◽  
Effect Of Therapy ◽  
Serum Therapy ◽  
The Difference ◽  
The Individual ◽  
And Control

Four hundred and twenty-two ewes, of a number of different breeds and ages (flocks 1–9) were used in experiments with hormones in the normal breeding season. Two main trials were conducted, the first making use of 377 animals, the second involving 45.Trial 1Three hundred and seventy-seven ewes were observed, in eight farm flocks, in a study of response to different treatments involving the administration of progesterone (in oil solution) and p.m.s. The trial sought to determine the effect of various dosage levels of progesterone and intervals of injection on the normal breeding performance of the ewe. Hormone treatment was applied at such time in the breeding season as to make it most improbable that conception would be limited by adverse animal or environmental factors. The aim was to determine the effect of the hormone technique per se on both immediate and long-term reproductive performance. Injection procedures and methods of flock management were arranged so that they might later be repeated in applications during the period of anoestrus.Two hundred and thirty-three ewes were injected intramuscularly with doses of progesterone in oil solution over a 7-day period. For eighty-nine ewes, four doses of 40 mg. were administered at 2-day intervals; for 144, 3 doses of 50 mg. were given at 3-day intervals. A single injection of 750 i.u. of p.m.s. was given subcutaneously to each ewe 2 days after the final dose of progesterone. One hundred and forty-four ewes remained untreated and served as a control.Progesterone therapy was effective in inhibiting oestrus and ovulation in the majority of ewes. Most injected animals came in oestrus 1–5 days following the injection of p.m.s.; 10% showed evidence of ‘silent heat’. 70% of ewes receiving progesterone at 2-day intervals and 68·2% of those receiving it at 3-day intervals conceived at the ‘controlled’ oestrus. 75% of the controls conceived at first mating. Treatment did not adversely affect the conception percentage to any appreciable extent.In animals conceiving at first oestrus, the average number of lambs born per ewe was 1·78 for injected and 1·44 for controls. In each flock there was an increase in lamb-crop, which would seem to be the result of the p.m.s. injection. Information on the effect of therapy on subsequent ewe fertility shows that 6·4% of ewes failed to conceive; this figure was the same for both treated and control animals. An attempt to use A.I. in conjunction with progesterone- p.m.s. therapy gave a conception percentage of 24, as compared with 68 in normally bred sheep.The results are discussed in relation to factors such as breed and age of ewe, and according to the particular mating procedure employed. There is no evidence that the forms of progesterone-p.m.s. therapy employed in this work would constitute a limiting factor to conception in out-of-season breeding.Trial 2The forty-five mature Welsh Mountain ewes used were in one flock. Each animal was injected on the 13th day of the oestrous cycle with a single dose of either 50 or 100 mg. of a micro-crystal suspension of progesterone. Two forms of suspension were used, the difference between the two being in the size of the individual crystals. Ewes came in oestrus 7–13 days following injection, the range for 50 mg. dosage being 7–13, and for 100 mg. 10–13 days. 25% of animals showed ‘silent heat’. Results suggest that injection of suspension adversely affects the normal expression of oestrus.

SECRETION OF LUTEINIZING HORMONE IN OVARIECTOMIZED ADULT RATS TREATED NEONATALLY WITH MONOSODIUM GLUTAMATE

1981 ◽  
Vol 91 (2) ◽  
pp. 341-346 ◽  
Author(s):  
R. G. DYER ◽  
R. F. WEICK ◽  
S. MANSFIELD ◽  
H. CORBET
Keyword(s):  
Monosodium Glutamate ◽  
Pulse Height ◽  
Treated Group ◽  
Experimental Manipulation ◽  
Ovariectomized Rats ◽  
Adult Rats ◽  
Blood Samples ◽  
Oestradiol Benzoate ◽  
And Control ◽  
Lh Secretion

We have studied the possible effects of monosodium glutamate (MSG) on LH secretion in ovariectomized rats. In experiment 1 MSG-treated and control rats were given oestradiol benzoate at noon and 72 h later half the rats in each group were given a second injection of oestradiol benzoate or progesterone. Blood samples were taken immediately before and 6 h after these i.m. injections. At 78 h there were no significant differences in plasma LH concentration measured in the two groups of rats given progesterone or in the two groups given a second injection of oestradiol benzoate although for both MSG-treated and control rats progesterone produced a significantly (P < 0·01) greater LH surge than did oestradiol benzoate. In experiment 2 100 μl blood samples were collected at 5-min intervals for up to 3 h from MSG-treated and control rats. For rats showing more than one pulsatile discharge of LH, peak and trough values for plasma LH concentrations were not significantly influenced by MSG treatment. However the mean pulse height was significantly (P < 0·001) greater in the MSG-treated group than in control rats. Pulsatile release stopped more quickly in the MSG-treated rats and their mean plasma LH concentration after 120 min of blood sampling was significantly (P < 0·05) lower than that obtained in the control animals. Thus, although some aspects of LH secretion seem to be significantly different in MSG-treated rats, these effects may result from the greater sensitivity of the MSG-treated animals to experimental manipulation.

scholarly journals Seasonal changes in the negative feedback regulation of the secretion of the gonadotrophins by testosterone and inhibin in rams

1999 ◽  
Vol 160 (1) ◽  
pp. 155-167 ◽  
Author(s):  
AJ Tilbrook ◽  
DM de Kretser ◽  
IJ Clarke
Keyword(s):  
Breeding Season ◽  
Negative Feedback ◽  
Plasma Concentrations ◽  
Feedback Regulation ◽  
Negative Feedback Regulation ◽  
Blood Samples ◽  
Vehicle Treatment ◽  
Breeding Seasons ◽  
Lh Secretion ◽  
Hypothalamic Level

Three experiments were conducted with castrated Romney Marsh rams (wethers) to investigate the ability of testosterone and inhibin to suppress the secretion of LH and FSH during the breeding and the non-breeding seasons. In Experiment 1, wethers (n=5/group) were treated every 12 h for 7 days with oil or 16 mg testosterone propionate (i.m.) and were then given two i.v. injections either of vehicle or of 0.64 microg/kg human recombinant inhibin A (hr-inhibin) 6 h apart. Blood samples were collected for 4 h before inhibin or vehicle treatment and for 6 h afterwards for the assay of LH and FSH. In Experiments 2 and 3 wethers underwent hypothalamo-pituitary disconnection (HPD) and were given 125 ng GnRH i.v. every 2 h. In Experiment 2, HPD wethers (n=3/group) were injected (i.m.) every 12 h with oil or testosterone and blood samples were collected over 9 h before treatment and 7 days after treatment. In Experiment 3, HPD (n=5/group) wethers were treated with vehicle or hr-inhibin, as in Experiment 1, after treatment with oil, or 4, 8 or 16 mg testosterone twice daily for 7 days. Blood samples were collected over 4 h before treatment with vehicle or hr-inhibin and for 6 h afterwards. Treatment of wethers with testosterone (Experiment 1) resulted in a significant decrease in the plasma concentrations of LH and number of LH pulses per hour but the magnitude of these reductions did not differ between seasons. Testosterone treatment had no effect on LH secretion in GnRH-pulsed HPD wethers in either season and treatment with hr-inhibin did not affect LH secretion in wethers or HPD wethers in any instance. Plasma concentrations of FSH were significantly (P<0.05) reduced following treatment with testosterone alone during the breeding season but not during the non-breeding season. FSH levels were reduced to a greater extent by treatment with hr-inhibin but this effect was not influenced by season. During the non-breeding season, the effect of hr-inhibin to suppress FSH secretion was enhanced in the presence of testosterone. These experiments demonstrate that the negative feedback actions of testosterone on the secretion of LH in this breed of rams occurs at the hypothalamic level and is not influenced by season. In contrast, both testosterone and inhibin act on the pituitary gland to suppress the secretion of FSH and these responses are affected by season. Testosterone and inhibin synergize at the pituitary to regulate FSH secretion during the non-breeding season but not during the breeding season.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

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