Adrenal glands alter the concentration of oestradiol-17β and its receptor in the uterus of ovariectomized ewes

Atkinson, Simon; Adams, N. R.

doi:10.1677/joe.0.1180375

Cited by 35 publications

(12 citation statements)

References 12 publications

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“…The Bo was 47%, the NSB was 3.6%, the minimal detectable concentration was 0.08 ng/ml and the ED50 was 3.84 ng/ml. Plasma cortisol were analysed using the method of Atkinson and Adams (1988). All samples were measured in a single assay.…”

Section: Analysesmentioning

confidence: 99%

The effect of ingesting a saltbush and barley ration on the carcass and eating quality of sheepmeat

Pearce

Pethick

Masters

2008

Animal

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Forage halophytes such as saltbush (Atriplex spp.) are widely used to revegetate Australian saline land and can provide a medium-quality fodder source. An animal house experiment was conducted to investigate differences in the carcass and eating quality of sheep ingesting saltbush from saline land in combination with a barley supplement. Twenty-six merino hoggets (two groups of 13) were fed either a 60 : 40 dried saltbush (Atriplex nummularia): barley (S 1 B) ration or a 33 : 25 : 42 lupins : barley : oaten hay ration (C) for 10 weeks prior to commercial slaughter. After 10 weeks, all sheep were commercially slaughtered and a single loin (from 12th rib to chump) collected from each animal for taste-panel analysis. Carcass weight, total tissue depth over the 12th rib 110 mm from the midline (GR fat depth), ultimate pH and colour were determined and X-ray bone densitometry used to estimate the fat content of the carcass. Blood samples were taken to assess the hormonal response to ingesting these diets and fatty acid profiles of the subcutaneous and intramuscular fat were determined. Both groups grew at the same rate (62 g/day) and had similar hot carcass weights (P . 0.01) (17.2 6 0.3 kg for S 1 B and 17.9 6 0.3 kg for C). However, these live weights may not be high enough to be commercially viable such that saltbush and barley may only be suitable as a maintenance feed. The S 1 B-fed sheep had a significantly (P 5 0.055) lower fat and higher lean content (P , 0.05) than the C group. This is a positive finding as fat denudation is a significant cost to processors and farmers can produce sheep that are depositing less fat or more lean per unit of live-weight gain. The decreased fat and increased lean content were attributed to the higher protein : energy ratio available for production and lower circulating insulin and higher growth hormone of the S 1 B-fed sheep. The lower body-fat content and lower metabolisable energy and digestible organic matter intake did correlate with the sheep fed the S 1 B diet, having a significantly lower percentage of unsaturated fat and equal levels of saturated fat than the C treatment. Diet had no effect on the ultimate pH or colour of the meat. Treatment had no significant effect on any of the eating-quality attributes (P . 0.1). The drying of the saltbush, the shorter length of the experimental period and the low carcass fat content were believed to have contributed to this result. Further field experiments are needed to clarify the benefits to carcass and eating quality of ingesting saltbush.

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Section: Analysesmentioning

confidence: 99%

The effect of ingesting a saltbush and barley ration on the carcass and eating quality of sheepmeat

Pearce

Pethick

Masters

2008

Animal

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“…Samples were assayed for FSH using a double-antibody radioimmunoassay provided by the pituitary agency of NIH and validated in our laboratory (Atkinson & Adams, 1988). Preparations NIAMDD-oFSH-RP-1 and NIAMDD-oFSH-I-1 were used for reference and iodination, respectively.…”

Section: Introductionmentioning

confidence: 99%

LH, FSH and ovulation rate in ewes treated with exogenous oestradiol

Atkinson

Adams²,

Martin³

1989

Reproduction

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Summary. In two experiments, mature Merino ewes were fitted with subcutaneous implants containing oestradiol-17\g=b\ or empty implants (control). Peripheral concentrations of LH and FSH were measured during luteal and follicular phases, which were synchronized by means of intravaginal progestagen-impregnated sponges. The ovulation rates of the ewes were determined by laparoscopy, 1 week after luteolysis. In Exp. 1, small implants (3 mm) decreased the LH pulse frequency before luteolysis. In the ewes with oestradiol implants, the amplitude of the preovulatory surge of LH was reduced and the onsets of the LH and FSH surges were delayed. There was no effect of oestradiol on LH baseline, LH pulse amplitude or in the concentration of FSH during the luteal or follicular phases. In Exp. 2, larger implants (10 mm) were inserted for the luteal, follicular, or luteal + follicular phases. The control ewes had empty implants. In the ewes with oestradiol implants, LH pulse frequencies were decreased during the luteal phase. This decrease persisted throughout the follicular phase, even though the oestradiol implants had been removed. There were no differences in the other measures of LH or FSH in the luteal or follicular phases. Ovulation rates were not affected by oestradiol treatment in either experiment, indicating that the regulation of LH pulse frequency is not a critical factor in the determination of ovulation rate in ewes. This was supported by retrospective analysis of the gonadotrophin profiles of single and twin-ovulating ewes, in which all measures of LH were similar between the two groups. However, twin-bearing ewes had slightly higher circulating concentrations of FSH during the luteal phase. As the difference in FSH was not large (13%), and it disappeared after luteolysis, it is difficult to postulate that FSH plays a major role in the final selection of the preovulatory follicle(s) in the ewe.

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“…This pathway was confirmed to be the one by which effects of acute treatment with glucocorticoids occur (Campbell 1978, Atkinson & Adams 1988, Rabin et al 1990. Acute treatment with glucocorticoids has been shown to greatly diminish oestrogenstimulated proliferative activity as well as the number of oestrogen receptors in all the uterine cell types (Atkinson & Adams 1988, Rabin et al 1990, Bigsby 1993). The present work also demonstrates a decrease in proliferation in the luminal and glandular epithelia, where the number of glucocorticoid receptors may also be reduced.…”

Section: Discussionmentioning

confidence: 76%

“…Almost all investigations of this process have clearly shown that glucocorticoids greatly diminish oestrogen-stimulated synthesis of DNA and activation of proliferation in the uterus (Tchernitchin et al 1975, Campbell 1978, Stewart et al 1983, Bigsby 1993. Moreover, the content of various factors and activity of various processes, such as ornithine decarboxylase activity (Stewart et al 1983), number of oestrogen receptors (Lisk & Reuter 1976, Markaverich et al 1981, Atkinson & Adams 1988, Rabin et al 1990, Zamorano et al 1992, blood flow (Monheit & Resnik 1981), protein synthesis (Lippe & Szego 1965, Sullivan et al 1983, prostaglandin synthesis (Dey et al 1982, Pakrasi et al 1983, Jacobs et al 1994), c-fos mRNA (Kirkland et al 1992), insulin-like growth factor-I mRNA (Sahlin 1995), associated or mediated oestradiol-induced increase in mitotic activity in the uterus, are also inhibited by glucocorticoids. However, it should be noted that all the researches so far have only demonstrated glucocorticoid action after acute or shortterm treatment, and there are no data on long-term effects of glucocorticoids on oestradiol-induced processes in the uterus.…”

Section: Introductionmentioning

confidence: 99%

Effect of long-term glucocorticoid treatment on oestradiol-induced proliferation in the uterus of ovariectomized rats

Гунин

1998

Journal of Endocrinology

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The aim of this study was to examine the effect of long-term treatment with glucocorticoids on the uterine response to oestradiol. Ovariectomized rats were treated with crystal triamcinolone acetonide (0·1 mg/100 g, i.m.) or saline (0·1 ml/100 g i.m.) for 29 days. Over this period five injections were administered, one per week. On the second day after the last triamcinolone injection, rats were treated with a single injection of oestradiol dipropionate (5 µg/100 g, s.c.) or vehicle (olive oil, 0·1 ml/100 g, s.c.). The effects of oestradiol in the uterus were determined by measuring mitotic index, bromodeoxyuridine (BrdU)-labelling index (BrdU was injected 2 h before the rats were killed; 2 mg/100 g, i.p.), and proliferating cell nuclear antigen (PCNA)-labelling index 24, 36 and 48 h after the injection of oestradiol or vehicle. Long-term treatment with glucocorticoids resulted in dissimilar changes in oestradiol-induced proliferation in epithelial and connective-tissue (stroma) components of the uterus. In luminal and glandular epithelia, there was an initial reduction in proliferation at 24 h, followed by an increase at 36 h and a further reduction at 48 h after the oestradiol injection. In stromal cells of the endometrium, triamcinolone treatment caused a large constant increase in oestradiol-induced proliferation throughout the experiment. The glucocorticoid treatment had no effect on the parameters without oestradiol administration.

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Adrenal glands alter the concentration of oestradiol-17β and its receptor in the uterus of ovariectomized ewes

Cited by 35 publications

References 12 publications

The effect of ingesting a saltbush and barley ration on the carcass and eating quality of sheepmeat

The effect of ingesting a saltbush and barley ration on the carcass and eating quality of sheepmeat

LH, FSH and ovulation rate in ewes treated with exogenous oestradiol

Effect of long-term glucocorticoid treatment on oestradiol-induced proliferation in the uterus of ovariectomized rats

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