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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Food deprivation inhibits ovulation and estrous behavior in golden hamsters. In experiment 1, the effects of phasic starvation (food deprivation on days 1 and 2 of the 4-day estrous cycle) depended on prior body weight and fat content. Starvation-induced anestrus, which occurs after only one cycle of phasic starvation in lean hamsters, did not occur until after three or more cycles in fat hamsters. None of the fat hamsters became anestrous until their body weights had declined to the level of lean hamsters. However, in experiment 2, we found evidence that changes in reproductive status were not signaled by any dimension of body size per se but instead by the general availability of metabolic fuels. Estrous cycles of thin hamsters were not significantly affected by food deprivation and weight loss when the hamsters were provided with either a 25% glucose solution or with vegetable shortening. In experiment 3, simultaneous pharmacological reduction of both fatty acid oxidation and glycolysis inhibited estrous cycles in hamsters fed ad libitum. Estradiol treatment restored estrous behavior, but not ovulation, in food-deprived, lean hamsters and in hamsters in which both fatty acid oxidation and glycolysis were reduced. Decreased availability of utilizable metabolic fuels may inhibit follicular development, which may in turn lead to circulating estradiol levels that are insufficient to stimulate estrous behavior.
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PMID:Decreased availability of metabolic fuels induces anestrus in golden hamsters. 231 19

Two trials were conducted to determine if estrogen contributes to development of fatty liver in dairy cattle. During trial 1, eight late lactation, nonpregnant cows were assigned to 0 or 15 mg estradiol-17 beta benzoate/d treatment. Days 1 to 3 of the trial were for baseline measurements, and treatments were given from d 4 to 21; on d 20 and 21 animals were fasted. Short-term feed deprivation resulted in increased plasma FFA concentrations and rapid accumulation of triglyceride into liver tissue obtained by biopsy. During starvation, plasma FFA concentration and liver triglyceride content were lower for cows receiving the estradiol-17 beta treatment relative to cows receiving control treatment. Very low density lipoprotein concentration in blood increased dramatically in three of four animals during estradiol-17 beta administration. Because of the decrease in milk production during estradiol-17 beta treatment, it was not known whether this represented a decrease in very low density lipoprotein clearance from blood or reflected a lipotropic response to estradiol-17 beta. Therefore, a second trial was conducted employing nonlactating cows, and control and estradiol-17 beta-treated animals were pair fed. The trial was 33 d with d 1 to 3 for baseline measurements, and treatments were administered from d 4 to 33. All animals were starved from d 19 to 23. Estradiol-17 beta increased hepatic lipid and triglyceride accumulation and plasma very low density lipoprotein concentration during starvation. Plasma FFA concentration was also increased by estradiol-17 beta during this time; therefore, a direct or indirect effect of estrogen on hepatic lipid metabolism could not be delineated.
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PMID:Estrogen induction of fatty liver in dairy cattle. 238 18

Reproductive capacity of female hamsters, as estimated by the ovulatory response, is particularly susceptible to interference by food deprivation. Previous studies showed that hamsters generally fail to ovulate if deprived of food for one or two estrous cycles. The present work demonstrates that starvation which is specific to the 2 days immediately after ovulation will block the next expected ovulation in approximately 80% of the animals. Such phasic starvation also resulted in significantly smaller ovarian follicle sizes. When placed with vigorous males, anovulatory animals failed to show lordosis behavior unless exogenous estradiol benzoate (EB) was supplied. With EB provided, all animals showed short-latency lordosis. These bioassay data suggested that poorly developed follicles were secreting insufficient estradiol for the facilitation of lordosis. Exogenous luteinizing hormone (LH) given 6 h before lights off on cycle day 4 failed to elicit ovulation, further suggesting that the follicles were not mature. Radioimmunoassay of LH and follicle-stimulating hormone (FSH) levels during the ovulatory gonadotropin surge showed that LH was vastly reduced, whereas FSH was in the low-to-normal range. Estradiol levels, assayed immediately before the gonadotropin surge, were low compared with controls, whereas progesterone levels were higher than normal. The results suggest that ovulatory failure in response to phasic food deprivation is a joint function of absence of an ovulatory LH surge and a set of immature follicles.
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PMID:Environment and hamster reproduction: responses to phase-specific starvation during estrous cycle. 376 65

Estradiol treatment of starving immature rainbow trout dramatically alters the metabolic performance of isolated hepatocytes. One and two weeks postimplantation with estradiol, the rate of de novo glucose synthesis from [14C]alanine is reduced fourfold from 0.4 mumol/g/hr to 0.1 mumol/g/hr, compared with vehicle-injected control fish. After 6 weeks, the rate of glucose production on a gram wet weight basis is identical in both treatment groups, but significantly larger (by 80%) in the estradiol-treated group than in the controls, if expressed normalized to the hepatosomatic index (HSI). Estradiol treatment caused preferential partitioning of alanine carbon into oxidative pathways away from gluconeogenesis, indicated by a significantly lower ratio of glucose production over CO2 production in hepatocytes isolated from estradiol-treated animals. Incorporation of [14C]alanine into acid-precipitable protein is significantly larger in the estradiol-treated group after 2 weeks, and also after 6 weeks, when normalized to the HSI, indicating that part of the protein synthesized in the estradiol-treated groups is vitellogenin. No differences were detected between estradiol-treated animals and control animals in the activities of enzymes associated with gluconeogenesis [phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase (FBPase)] and amino acid metabolism (alanine and aspartate aminotransferases) in the time course investigated (expressed on a wet weight basis). Activities normalized to the HSI are higher in fish implanted with estradiol compared with controls at 2 and 6 weeks. In keeping with the increased potential of hepatocytes for CO2 production from alanine, estradiol treatment doubled and tripled the maximum activity of pyruvate kinase 1 and 2 weeks postimplantation, respectively. Fish were fasted to avoid erratic feeding due to treatments. Superimposed on estradiol actions are effects of starvation: a fourfold increase in the rate of gluconeogenesis, a threefold increase in oxidative flux, and a fivefold increase in the activity of FBPase--all normalized to hepatocyte weight.
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PMID:Gluconeogenesis in hepatocytes of immature rainbow trout (Oncorhynchus mykiss): control by estradiol. 767 84

Estradiol was administered to 3 steers (0.12 mg/kg of body weight/d for 14 consecutive days), followed by 2 days of nonfeeding (starvation). During estradiol administration, liver nuclear estrogen receptor and serum apolipoprotein B-100 (apoB-100), as well as serum triglycerides concentrations were increased, compared with values before administration. Starvation, together with interruption of estradiol administration, resulted in rapid decreases of the receptor, serum apoB-100, and serum triglycerides concentrations, and increase of nonesterified fatty acids concentration. Of the 3 steers, 2 had higher liver triglyceride content, compared with values before treatment. In the control group (3 steers that received vehicle alone, then starved similarly), these concentrations, except for serum nonesterified fatty acids and triglycerides concentrations after starvation, were not changed. In another experiment, serum apoB-100 concentration in dairy cows was significantly (P < 0.05) lower at parturition than values before and after parturition. These results indicate that estradiol may be involved in development of fatty liver in cattle.
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PMID:Effect of estradiol administration and subsequent nonfeeding on liver estrogen receptor, serum apolipoprotein B-100, and serum triglycerides concentrations in steers. 823 36