Suppression and stimulation of TSH and thyroid hormones in bulls during starvation and refeeding

1983 ◽  
Vol 103 (2) ◽  
pp. 223-226 ◽  
Author(s):  
Borghild Tveit ◽  
Flemming Larsen
Keyword(s):  
Half Life ◽  
Experimental Period ◽  
Starvation Period ◽  
Disappearance Rate ◽  
Fasting Period ◽  
Blood Samples ◽  
Bull Calves ◽  
Ad Libitum ◽  
Ad Libitum Feeding ◽  
Stimulation Of

Abstract. Sixteen bull calves were fasted during two periods, 3½ and 7 months old. Blood samples were taken every 6 h during an experimental period of 9 days: 2 control days, 5 fasting days and 2 refeeding days. During the control days with ad libitum feeding, T3, T4 and TSH increased during the day. During the fasting period, T4 decreased with a half-life of 3.5 days and T3 with a half-life of 3 days. TSH decreased in a less regularly way to a mean of 60% of control mean. Six h after refeeding, TSH had increased to 300% of control mean. T3 and T4 had a maximum 12 h after refeeding. As the T4 decreased with a rate nearly similar to the T4 disappearance rate in starving bulls, the secretion of T4 from the thyroid gland must have been almost stopped during the starvation period. The morning values were below normal for all three hormones after 2 days of refeeding.

Nitric Oxide Signals That Aplysia Have Attempted to Eat, a Necessary Component of Memory Formation After Learning That Food Is Inedible

2006 ◽  
Vol 96 (3) ◽  
pp. 1247-1257 ◽  
Author(s):  
Ayelet Katzoff ◽  
Tziona Ben-Gedalya ◽  
Itay Hurwitz ◽  
Nimrod Miller ◽  
Yehoshua Z. Susswein ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Methylene Blue ◽  
Rejection Rate ◽  
Memory Formation ◽  
Critical Component ◽  
No Donor ◽  
Ad Libitum ◽  
Ad Libitum Feeding ◽  
Insight Into ◽  
Stimulation Of

Inhibiting nitric oxide (NO) synthesis during learning that food is inedible in Aplysia blocks subsequent memory formation. To gain insight into the function of NO transmission during learning we tested whether blocking NO synthesis affects aspects of feeding that are expressed both in a nonlearning context and during learning. Inhibiting NO synthesis with L-NAME and blocking guanylyl cyclase with methylene blue decreased the efficacy of ad libitum feeding. D-NAME had no effect. L-NAME also decreased rejection responses frequency, but did not affect rejection amplitude. The effect of L-NAME was explained by a decreased signaling that efforts to swallow are not successful, leading to a decreased rejection rate, and a decreased ability to reposition and subsequently consume food in ad libitum feeding. Signaling that animals have made an effort to swallow is a critical component of learning that food is inedible. Stimulation of the lips with food alone did not produce memory, but stimulation combined with the NO donor SNAP did produce memory. Exogenous NO at a concentration causing memory also excited a key neuron responding to NO, the MCC. Block of the cGMP second-messenger cascade during training by methylene blue also blocked memory formation after learning. Our data indicate that memory arises from the contingency of three events during learning that food is inedible. One of the events is efforts to swallow, which are signaled by NO by cGMP.

The effects of zeranol on performance and carcass characteristics of young bulls

1986 ◽  
Vol 1986 ◽  
pp. 94-94
Author(s):  
B M Scott ◽  
A V Fisher ◽  
R A Cooper ◽  
J A Kirk
Keyword(s):  
Growth Performance ◽  
Crude Protein ◽  
Dry Matter ◽  
Carcass Characteristics ◽  
Carcass Quality ◽  
Blood Samples ◽  
Chemical Company ◽  
Holstein Bull ◽  
Bull Calves ◽  
Ad Libitum

Kirk and Cooper (1983) reported two experiments in which the growth performance and carcass conformation of intensively fed dairy-bred bulls was improved by sequential implantation with Zeranol®. Two further studies have been conducted in which there has been repeat implantation of Zeranol® and detailed carcass dissection to measure precisely the effects on carcass quality.In trial A, 16 Holstein bull calves were purchased from pedigree breeders and weaned at eight weeks of age, when they were divided into two groups of eight, balanced by weight. From 8 to 12 weeks they were given commercial rearing pellets followed by a. commercial pencil and hay was given ad libitum. From 12 weeks onwards a cereal mix was offered ad libitum, formulated to give 13 MJ/kg dry matter, 160 g/kg crude protein. Hay was withdrawn from 14 weeks of age. At eight weeks of age, half the animals were implanted with 36 mg Zeranol® (Ralgro, Crown Chemical Company, Kent), and re-implanted a further three times every 70 days. Five blood samples were taken from all animals over a 15h period at about 8, 14, 33 and 43 weeks of age.

scholarly journals Energy partition for maintenance and weight gain in Nellore and crossbred steers finished under grazing

2011 ◽  
Vol 40 (4) ◽  
pp. 922-928
Author(s):  
N.F. Sant´Ana ◽  
C.A.A. Fontes ◽  
E.F. Processi ◽  
J.G. Siqueira ◽  
A.M. Fernandes ◽  
...  
Keyword(s):  
Body Weight ◽  
Linear Model ◽  
Reference Group ◽  
Experimental Period ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Full Time ◽  
Indicator Method ◽  
Ad Libitum ◽  
Ad Libitum Feeding

The objective of this work was to estimate net energy (NEm) and metabolizable energy (MEm) requirements for maintenance and efficiency of use of metabolizable energy for maintanence (k m) and gain (k g) of grazing Nellore and crossbred steers. It was used 24 castrated steers, 12 Nellore breed (386 kg SBW) and 12 ½ Limousin-Nelore crossbred (397 kg SBW). The comparative slaughter method was used. In each genetic group, animals were grouped in three similar groups: reference; restrict feeding and ad libitum feeding. The reference group was slaughtered in the beginning of the experiment whereas the others were slaughtered at the end of it. During the 104 days of the experimental period, the group under restrict feeding had access to pastures for 3.5 hours daily whereas the group with ad libitum feeding remained on pasture full time. Forage intake was estimated in two trials by using the double-indicator method. Values of NEm, MEm, k m and k g were estimated on the basis of empty body weight (EBW) through linear and non-linear model fitting. Requirements of NEm and MEm did not differ among Nellore and crossbred animals. In the linear model, the following results were obtained: Requirements of NEm = 86 kcal/kg0.75; requirements of MEm = 136 kcal/kg0.75 and k m = 0.63. Kg value was higher for Nellore animals (0.39) than for crossbred animals (k g = 0.33). Requirement of net energy of maintenance does not differ among grazing Nellores and ½ European-Nellore crossbred. For the same body weight, Nellore animals present greater fat proportion in gain composition than ½European-Nelore crossbred.

Effects of restricted daily feeding on neuropeptide Y release in the rat paraventricular nucleus

1996 ◽  
Vol 270 (4) ◽  
pp. E589-E595 ◽  
Author(s):  
T. Yoshihara ◽  
S. Honma ◽  
K. Honma
Keyword(s):  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Nucleus Tractus Solitarius ◽  
Fixed Time ◽  
Time Of Day ◽  
Fasting Period ◽  
Daily Feeding ◽  
Neuropeptide Y Release ◽  
Ad Libitum ◽  
Ad Libitum Feeding

Extracellular neuropeptide Y (NPY) in the vicinity of the paraventricular nucleus (PVN) and the NPY concentrations in the PVN, arcuate nucleus of the hypothalamus (ARC), and the nucleus tractus solitarius (NTS) were measured in rats under ad libitum and restricted daily feeding (RF) where meal was supplied at a fixed time of day. The extracellular NPY levels did not vary significantly between 0600 and 2200 in rats under ad libitum feeding but were increased before meal and decreased immediately after mean supply under the RF regimen. Similarly, the NPY concentrations in the PVN, ARC, and NTS were increased immediately before meal. When meal was omitted at the regular mealtime, the extracellular NPY levels were not decreased rapidly, and the NPY concentration in the PVN remained at a low level. Rats were subjected to the feeding-fasting paradigm after the termination of RF. The extracellular NPY levels were returned to basal levels during the feeding period but were elevated during the fasting period at almost the same time as that for meal supply under the RF regimen. It is concluded that the prefeeding enhancement of the NPY release in the PVN under the RF regimen is regulated by the feeding-associated circadian rhythm.

scholarly journals Changes in bone density and bone quality caused by single fasting for 96 hours in rats

PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6161 ◽  
Author(s):  
Yuko Hisatomi ◽  
Kenji Kugino
Keyword(s):  
Bone Density ◽  
Bone Quality ◽  
Time Course ◽  
Experimental Period ◽  
Bone Architecture ◽  
Control Group ◽  
Fasting Period ◽  
Cross Sectional ◽  
Polar Moment ◽  
Ad Libitum

Background Young women occasionally engage in dietary restrictions accompanied by fasting for the purpose of losing weight, but such restrictions have various effects on body functions. The recent increase in the number of people suffering from osteoporosis has become a major social problem mainly in industrialized countries.Therefore, we think it is important to understand the effects of fasting on bone vulnerability, especially to bone quality. Methods Animals used male Wister rats weighing 130 g (6 weeks of age), and were divided into a control group (n = 5) and a fasting group (n = 6). The experimental period was 14 days, the control group had ad libitum food throughout the experimental period, the fasted group was fasted for 4 days, and than, had ad libitum food for 10 days. In this study, parameters related to bone fragility due to three-dimensional bone architecture were determined on Contrast enhanced micro-CT images of the lumbar spine and were used as a method for the evaluation of bone quality. In addition, a time-course observation of each individual was carried out during the fasting period and later upon resuming food intake. Cross-sectional images of all vertebrae were obtained from radiographic computed tomography and were analyzed by using Latheta software ver. 3.0 (Hitachi-Aloka Medical, Nagasaki, Japan). The region of interest that was misrecognized in each cross-sectional image was made consistent with the anatomical structure by carrying out corrections manually and by identifying the cortical bone areas and cancellous bone areas. Results Our findings showed that while single fasting for 96 h did not cause any major change in the macroscopic morphology of bone, it caused a marked decrease in bone density. In addition, the minimum cross-sectional moment, which indicated the “strength against bending” as well as the polar moment that indicated the “strength against torsion” were both lower than in non-fasted rats. Further, after resumption of feeding, bone mineral content in the fasting group recovered rapidly and starting at day 4 after resumption of feeding, there was no difference with the control group. On the other hand, the values of the minimum cross-sectional moment and polar moment did not recover, and the difference with the control group increased during the feeding period. Discussion On the basis of this study, the authors estimate that the fasting-induced decrease in bone minimum cross-sectional moment and polar moment may have been due to changes affecting some factors involved in bone quality, and thus could be useful as a parameter in future studies aimed at elucidating bone quality. At least, in the case where bone change accompanied with a change in macroscopic distribution of mineral components occurs, the values of minimum cross-sectional moment and polar moment are considered to be bone parameters that will provide valuable information to elucidate bone quality.

UREA AS A NITROGEN SUPPLEMENT IN STARTER FEEDS FOR EARLY WEANED CALVES

1973 ◽  
Vol 53 (2) ◽  
pp. 339-343 ◽  
Author(s):  
K. A. WINTER
Keyword(s):  
Conversion Efficiency ◽  
Soybean Meal ◽  
Economic Advantage ◽  
Feed Conversion ◽  
Feed Conversion Efficiency ◽  
Holstein Bull ◽  
Bull Calves ◽  
Ad Libitum ◽  
Feed Costs ◽  
Ad Libitum Feeding

Calf starter feeds containing either urea or soybean meal as a source of supplementary nitrogen were evaluated as the sole ration for Holstein bull calves weaned at 5 or 6 wk of age. In two experiments using a total of 56 calves, weight gains of the urea-fed calves (0.72–0.88 kg/day) were similar to or slightly less than the soybean meal-fed calves (0.77–0.90 kg/day). Except for one treatment in experiment 1, intake of the urea-supplemented starters was slightly less than intake of the soybean meal-supplemented starters. Feed conversion efficiency of the urea-supplemented starters was poorer in experiment 1, but comparable with the soybean meal-supplemented starters in experiment 2. The use of urea in the calf starters resulted in reduced feed costs ranging from $3.47 to $4.07 per 100 kg; and reductions in feed costs per 100 kg gain ranged from $9.34 to $12.90. Although animal performance may be slightly reduced by urea supplementation of calf starters, an economic advantage in feed costs was demonstrated with the use of urea when ad libitum feeding was practiced.

DISAPPEARANCE RATE OF BOVINE PROLACTIN FROM PLASMA OF FEMALE RATS STUDIED AT INTERVALS OF UP TO 160 MINUTES BY RADIOIMMUNOASSAY

1970 ◽  
Vol 64 (4) ◽  
pp. 718-725 ◽  
Author(s):  
A. A. van der Gugten ◽  
H. G. Kwa
Keyword(s):  
Intravenous Administration ◽  
Female Rats ◽  
Disappearance Rate ◽  
Blood Samples ◽  
Dose Dependent

ABSTRACT Plasma values resulting from the intravenous administration of 300, 100, 30 and 10 μ of bovine prolactin to rats on day 1 of pregnancy were followed by taking blood samples after 10, 20, 40, 80 and 160 minutes respectively. The rate of disappearance was found to be dose-dependent and to vary in time in the same rat. It is suggested that at least two processes of elimination take place: 1. a (possibly excretory) process, which can bring »unphysiologically high« prolactin levels down to approximately its treshold level of 1.7 μg/ml and 2. a process, which breaks down the hormone into »immunoreactive« polypeptides. This process can degrade 10 μg of bovine prolactin quantitatively within 10 minutes, but appears to become rapidly »saturated« by larger amounts of the hormone.

GnRH-1, GnIH mRNA and Luteinizing Hormone in Domestic hens (Gallus gallus domesticus) Exposed to Different Wavelengths of light

2017 ◽  
Vol 6 (8) ◽  
pp. 5446
Author(s):  
Reddy I.J. ◽  
Ashish Mishra ◽  
Mondal S.
Keyword(s):  
Luteinizing Hormone ◽  
Mrna Expression ◽  
Egg Production ◽  
Experimental Period ◽  
Treated Group ◽  
Lower Number ◽  
Gallus Gallus Domesticus ◽  
Blood Samples ◽  
Mrna Concentration ◽  
Normal Spectrum

The objective of this study was to establish the effects of red spectrum of light (650nm, treated n=12) and normal spectrum of light (450nm control=12) on GnRH-I and GnIH mRNA expression, amplitude and frequency of luteinizing hormone (LH) and egg production from 42 to 52 weeks of age in white leghorn hens. Blood samples were collected at weekly interval from both the groups. At the 47th week of age blood samples from both the groups were collected at every 3 h for 36h to study the pulsatile secretion of LH surges. GnRH and GnIH mRNA expression pattern was studied between control and treated birds. Egg production and pause days were calculated between the two groups. LH concentration in the plasma was increased significantly (P<0.01) in hens exposed to red spectrum of light. Plasma LH concentration was higher (P<0.01) in treated birds with more number of LH surges. The amplitude and frequencies of LH were advanced in birds exposed to red spectrum of light during 36 h of sampling at 3h intervals. GnRH-I mRNA concentration was significantly (P<0.01) higher, whereas GnIH mRNA was significantly (P<0.01) lower in birds exposed to red spectrum of light compared to controls. It is hypothesized that exposure of birds to red spectrum of light enhanced (P<0.01) GnRH-I mRNA, along with LH required for ovulation and egg lay. During 77 days (42-52 weeks of age) of the experimental period, egg production was increased (p<0.01) with lower incidence of pause days in the treated group. It is concluded that low GnIH mRNA and higher levels of GnRH-I mRNA, LH, lower number of pause days enabled the birds to lay more eggs by stimulating GnRH through red spectrum of light.

scholarly journals Feasibility of Extrapolating Randomly Taken Plasma Samples to Trough Levels for Therapeutic Drug Monitoring Purposes of Small Molecule Kinase Inhibitors

2021 ◽  
Vol 14 (2) ◽  
pp. 119
Author(s):  
Ruben A. G. van Eerden ◽  
Esther Oomen-de Hoop ◽  
Aad Noordam ◽  
Ron H. J. Mathijssen ◽  
Stijn L. W. Koolen
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Small Molecule ◽  
Trough Concentration ◽  
Drug Monitoring ◽  
Half Life ◽  
Kinase Inhibitors ◽  
Therapeutic Drug ◽  
Blood Samples ◽  
Elimination Half ◽  
Trough Levels

Small molecule kinase inhibitors (SMKIs) are widely used in oncology. Therapeutic drug monitoring (TDM) for SMKIs could reduce underexposure or overexposure. However, logistical issues such as timing of blood withdrawals hamper its implementation into clinical practice. Extrapolating a random concentration to a trough concentration using the elimination half-life could be a simple and easy way to overcome this problem. In our study plasma concentrations observed during 24 h blood sampling were used for extrapolation to trough levels. The objective was to demonstrate that extrapolation of randomly taken blood samples will lead to equivalent estimated trough samples compared to measured Cmin values. In total 2241 blood samples were analyzed. The estimated Ctrough levels of afatinib and sunitinib fulfilled the equivalence criteria if the samples were drawn after Tmax. The calculated Ctrough levels of erlotinib, imatinib and sorafenib met the equivalence criteria if they were taken, respectively, 12 h, 3 h and 10 h after drug intake. For regorafenib extrapolation was not feasible. In conclusion, extrapolation of randomly taken drug concentrations to a trough concentration using the mean elimination half-life is feasible for multiple SMKIs. Therefore, this simple method could positively contribute to the implementation of TDM in oncology.

scholarly journals Endocrine and Electrolyte Balances during Periovulatory Period in Cycling Mares

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 520 ◽  
Author(s):  
Katiuska Satué ◽  
Esterina Fazio ◽  
Ana Muñoz ◽  
Pietro Medica
Keyword(s):  
Estrous Cycle ◽  
Hpa Axis ◽  
Adrenocorticotropic Hormone ◽  
Venous Blood ◽  
Competitive Elisa ◽  
Direct Relation ◽  
Plasma Acth ◽  
Blood Samples ◽  
Hypothalamic Pituitary Adrenal ◽  
Stimulation Of

In cycling females, the periovulatory period is characterized by stimulation of the hypothalamic pituitary adrenal (HPA) axis. The aim of present study was to analyze the pattern and interrelationships among adrenocorticotropic hormone (ACTH), cortisol (CORT), aldosterone (ALD) and electrolytes (sodium—Na+, potassium—K+ and chloride—Cl−) during periovulatory period in cycling mares. Venous blood samples were obtained daily from a total of 23 Purebred Spanish broodmares, aged 7.09 ± 2.5 years, from day −5 to day +5 of estrous cycle, considering day 0, the day of ovulation. Plasma ACTH was measured by a fluorescent immunoassay kit, serum CORT and ALD by means of a competitive ELISA immunoassay, and plasma Na+, K+ and Cl− were quantified by an analyzer with selective electrodes for the three ions. ACTH showed higher concentrations at day 0 compared to days −5 to −1 and +1 to +3 (p < 0.05). CORT showed higher concentrations at day 0 compared to days −5 to −2 and +1 to +5 (p < 0.05). ALD showed higher concentrations at day 0 compared to days −5 to −2 (p < 0.05) and +2 (p < 0.05). Na+ and Cl− showed higher concentrations at day 0, compared to day −5 and +5. K+ showed lower concentrations at day 0 compared to day +1 (p < 0.05). The significant correlations obtained between ACTH and CORT (r = 0.20) and between ACTH and ALD (r = 0.32) suggest that although ACTH may have an effect both on CORT and ALD, there are other very important determinants that could be considered. Hence, it is possible to presume that the pituitary adrenocortical response and ALD may be involved in the ovulatory mechanisms without a direct relation with electrolyte pattern.

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