Increase in plasma progesterone caused by undernutrition during early pregnancy in the ewe

Cumming, I. A.; Bj, Mole; Obst, JM; Ma, Blockey; Cg, Winfield; Goding,

doi:10.1530/jrf.0.0240146-a

Cited by 23 publications

(14 citation statements)

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“…This influence of the sympathetic nerves on ovarian progesterone secretion explains the increased pro¬ gesterone concentrations in response to the stress of undernutrition (Cumming, Mole, Obst et al 1971), and of low (Lamond, Gaddy & Kennedy, 1972) and high (Wheeler & Blackshaw, 1986) ambient tempera¬ tures. Differences in progesterone concentrations between breeds (Wheeler & Land, 1977) may be due to a genetic variation in the sympathetic tone, such a variation being suggested by the differences in the non-esterified fatty acid concentrations between breeds (Wheeler, 1984).…”

Section: Discussionmentioning

confidence: 97%

Peripheral progesterone concentrations in the luteal-phase ewe: effects of a β-adrenergic receptor antagonist and two β2-adrenergic agonists

Wheeler

Lean²,

Walker³

1988

Journal of Endocrinology

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Peripheral blood samples were collected at 10-min intervals from three conscious sheep in which ovulation had been induced 6-10 days previously using exogenous hormones. Saline was infused into a jugular vein for about 1 h, followed by the experimental drug for 1-2 h and followed by saline again for a further 2 h. The experiments were repeated following induced luteolysis and ovulation. The infusion of a beta-adrenergic antagonist (propranolol) into three conscious luteal-phase ewes decreased (P less than 0.05) the peripheral progesterone concentration in each animal. Infusions of beta 2-adrenergic agonists (ritodrine and salbutamol) increased (P less than 0.05) the progesterone concentration in four out of eight experiments. The beta-adrenergic antagonist decreased the heart rate and the beta 2-adrenergic agonist increased it; the arterial blood pressure and respiratory rate were unaffected. The decrease in the progesterone concentration in response to the beta-adrenergic antagonist suggests that the normal ovarian secretion of progesterone is partly the result of sympathetic stimulation, and that the sympathetic innervation of the ovary may have a physiological role in modulating progesterone secretion.

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Section: Discussionmentioning

confidence: 97%

Peripheral progesterone concentrations in the luteal-phase ewe: effects of a β-adrenergic receptor antagonist and two β2-adrenergic agonists

Wheeler

Lean²,

Walker³

1988

Journal of Endocrinology

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“…Thus, the higher progesterone levels found in Group L ewes, combined with the absence of a relationship between pro¬ gesterone and litter size when the ewes achieved a uniform nutritional state, stress the effect of nutrition on the maternal plasma progesterone and indicate the use of plasma progesterone as a possible criterion for the assessment of nutritional state in sheep. Cumming et al (1971) suggested that the increase in plasma progesterone may be due to decreased metabolic rate, mobilization of stores of progesterone or increased rate of secretion. The change in plasma progesterone was not, however, accompanied by a change in LH or ACTH levels (Cumming et al, 1971) and, in the present study, the changes of LH concentrations were different from those of progesterone and no direct re¬ lationship could be seen.…”

Section: Discussionmentioning

confidence: 99%

“…Cumming et al (1971) suggested that the increase in plasma progesterone may be due to decreased metabolic rate, mobilization of stores of progesterone or increased rate of secretion. The change in plasma progesterone was not, however, accompanied by a change in LH or ACTH levels (Cumming et al, 1971) and, in the present study, the changes of LH concentrations were different from those of progesterone and no direct re¬ lationship could be seen. The rise in plasma progesterone during undernutrition in the ewe may have evolved to reduce pregnancy loss during periods of under¬ nutrition, but the cause remains unclear.…”

Section: Discussionmentioning

confidence: 99%

THE EFFECTS OF NUTRITION ON THE REPRODUCTIVE PERFORMANCE OF FINN x DORSET EWES

Shevah¹,

Wj²,

Wr³

et al. 1975

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Progesterone and LH concentrations were measured in the plasma of blood samples taken from forty-eight pregnant ewes on Days 100, 120 and 134 of gestation. The ewes, in two groups of twenty-four were maintained from Day 100 until parturition on two planes of nutrition which supplied daily energy and protein intakes of about 4-1 or 2-3 Mcal metabolizable energy and either 192 or 111 g digestible crude protein per ewe. Within the groups, the ewes carried one, two or three fetuses and the feed intake was adjusted according to litter size to produce a uniform nutritional state within the group. On Day 100, litter size affected the concentration of plasma progesterone (P less than 0-001), but had no effect on Days 120 or 134 when the ewes were fed according to litter size. The low feed intake however caused a significant increase in plasma progesterone concentrations. The LH concentrations showed no major changes during late pregnancy and no effect of nutrition or little size on the plasma hormone concentration was observed. It was concluded that the effect of litter size on plasma progesterone concentration recorded on Day 100 or gestation was partly mediated by level of nutrition.

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“…Undernutrition of the sheep results in greater peripheral progesterone concentrations (Cumming et al, 1971). Similarly, extreme (stressful) ambient temperatures, both low (ewes: Lamond et al, 1972;cows: Rosenberg et ai, 1982;buffalo cows: Rao & Pandey, 1982) and high (cows: Stott & Wiersma, 1973;ewes: Wheeler & Blackshaw, 1986), have been associated with increased peripheral progesterone concentrations.…”

Section: Discussionmentioning

confidence: 99%

Influence of adrenergic receptors on ovarian progesterone secretion in the pseudopregnant cat and oestradiol secretion in the oestrous cat

Wheeler¹,

Walker²,

Lean³

1987

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Summary. The infusion of isoprenaline or propranolol into the abdominal aorta of the pseudopregnant cat caused an increase or decrease respectively in the ovarian progesterone secretion rate. These observations suggest that the sympathetic innervation of the ovary has a physiological influence on normal progesterone secretion, and this mechanism may explain stress-related increases in progesterone concentrations. The infusion of isoprenaline or propranolol after the stimulation of follicular growth had no consistent or convincing effect on oestradiol secretion.

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Increase in plasma progesterone caused by undernutrition during early pregnancy in the ewe

Cited by 23 publications

References 0 publications

Peripheral progesterone concentrations in the luteal-phase ewe: effects of a β-adrenergic receptor antagonist and two β2-adrenergic agonists

Peripheral progesterone concentrations in the luteal-phase ewe: effects of a β-adrenergic receptor antagonist and two β2-adrenergic agonists

THE EFFECTS OF NUTRITION ON THE REPRODUCTIVE PERFORMANCE OF FINN x DORSET EWES

Influence of adrenergic receptors on ovarian progesterone secretion in the pseudopregnant cat and oestradiol secretion in the oestrous cat

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