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Effect of nutrition on the balance of production of ovarian and pituitary hormones in ewes


, : Effect of nutrition on the balance of production of ovarian and pituitary hormones in ewes. Animal Reproduction Science 45(1-2): 59-70

Nutrition-induced changes in liveweight can induce changes in ovarian function and ovulation rate. This study was designed to test the hypothesis that heavy ewes are able to maintain similar concentrations of follicle-stimulating hormone (FSH) to light ewes through a loss of responsiveness to ovarian negative feedback. This hypothesis leads to the prediction that administration of ovarian hormones on the basis of metabolic body weight would result in the same gonadotrophin (FSH) concentrations in light and heavy ovariectomized ewes. We therefore examined the ovarian content of oestradiol and inhibin, and the FSH response to administration of these ovarian hormones in acutely ovariectomized heavy and light Merino ewes produced by differential feeding. At ovariectomy, follicular fluid was aspirated from the 6 largest follicles in each ewe and assayed for oestradiol and inhibin. Six days later, blood was sampled every 6 h for 2 days. Ewes were then given two subcutaneous progesterone implants and injected subcutaneously every 6 h for 5 days with oestradiol (37.4 ng kg-0.75) and charcoal-stripped bovine follicular fluid (0.04 ml kg-0.75). Blood was sampled before each injection and the plasma was assayed for FSH and inhibin. Oestradiol and its receptors were assayed in uterine tissue. Nutrition-induced increases in liveweight led to increases in the number of oestrogenic, potentially ovulatory ovarian follicles and the total ovarian content of oestradiol and inhibin. In the uterus, more oestradiol receptors and a higher oestradiol uptake were observed in light than in heavy ewes. After ovariectomy, FSH concentrations were inversely related to liveweight. However, when the ewes were treated with doses of ovarian hormones that were proportional to liveweight, the slope of the decline in FSH concentrations was independent of liveweight. We conclude that nutrition alters the balance between pituitary FSH secretion and gonadal feedback by changing the responsiveness to the inhibitory effects of oestradiol and inhibin.

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Accession: 002815497

PMID: 9227912

DOI: 10.1016/s0378-4320(96)01552-7

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Campbell, C.B.; McGuffie, C.; Weedon, A.P.; Powell, L.W., 1977: Cholestatic liver disease associated with diphenylhydantoin therapy. Possible pathogenic importance of altered bile salt metabolism. A ten-year-old boy persented with a prolonged cholestatic liver disease 5 weeks after starting diphenylhydantoin therapy. The initial phase of his illness was characterized by hepatocellular damage with swollen liver cells and centrilobular choles...

Locket, GH., 1982: Some linyphiid spiders from western Malaysia. Bulletin of the British Arachnological Society, 58: 361-384

Czajkowski, M., 1973: La gorgebleue Luscinia svecica nicheuse dans la basse vallee de l'Ain. Nos Oiseaux, 324: 99-102

Stinear, C.M.; Byblow, W.D., 2004: Impaired modulation of intracortical inhibition in focal hand dystonia. Previous studies have shown that intracortical inhibition (ICI) plays an important role in shaping the output from primary motor cortex, and that ICI may be impaired in people with Focal Hand Dystonia (FHD). This study explored the muscle-specific...

Buchowski M.S.; Mahoney A.W.; Carpenter C.E.; Cornforth D.P., 1988: Heating and the distribution of total and heme iron between meat and broth. The effect of heat on movement of total and heme iron from meat to broth was investigated. Total iron by a wet ash method was nearly identical to the sum of heme iron plus nonheme iron. The total amount of nonheme iron increased with cooking tempe...

Trimmer, P.A.; Wunderlich, R.E., 1990: Changes in astroglial scar formation in rat optic nerve as a function of development. Although astroglial scar formation is a common response to almost any type of injury to the adult central nervous system, lesions in fetal and neonatal rats have been reported to induce little or no scar formation. To examine this developmental di...

Godard C., 1968: Hypo natremia and anti diuresis in purulent meningitis. Pediatria Pratica 39(6): 350

Ades, I.Z., 1989: Characterization of chicken liver L-alanine:4,5-dioxovaleric acid aminotransferase. 1. A procedure is described for purifying the enzyme L-alanine:4,5-dioxovaleric acid aminotransferase (DOVA transaminase) from chicken liver. The enzyme catalyzes a transamination reaction between L-alanine and 4,5-dioxovaleric acid (DOVA), yieldi...

Tekavec, C., 2008: What's happening in the world of electronic records? Part 2. Dentistry Today 27(6): 116-117

Molins, L.; Cañadell, A.M.; Rodríguez-Méndez, F.; Galofré, M., 1986: Clinical diagnosis and fine needle puncture-aspiration of solid tumors of the breast. Medicina Clinica 86(14): 582-586