influence of administration of different doses of arginine and lysine coupled with zinc in the lactating ewes on the zinc concentration in milk

Zinc [Zn] plays an essential role in the human and animal body system. Zinc deficiency might cause many disorders, so it is important to provide a sufficient amount of this microelement in both animals and humans. One of the most important sources of Zn is milk. The purpose of this study was to determine whether Zn can pass through the mammary epithelial cell into milk by a cotransport system with amino acid in the lactating ewes. This experimental research included 54 lactating ewes collected from the Agriculture-Jahad Organization of Tehran Province, that were allocated into 9 groups as follows: groups which received inorganic form as Zn chloride [1, 2 and 4 mg/kg], and groups which received organic Zn with different doses of arginine or lysine [1, 2 and 4 mg/kg] in chelate form. Milk samples were taken 30 min before and 6 h after intravenous injection of Zn preparations. Zinc concentration in milk was measured using the flame atomic absorption spectrometric method. There were no significant differences [P>0.05] between groups in Zn concentration of the milk before administration of inorganic or organic Zn. Data analysis showed that administration of inorganic Zn caused a significant increase of Zn concentration in the milk in a dose dependent manner. While administration of arginine or lysine with Zn in chelate form caused a significant decline in Zn concentration of milk compared to inorganic Zn in a dose dependent manner. According to our results, administration of different forms of Zn influenced the Zn concentration in milk

[Effect of orexin in ventromedial and lateral hypothalamus on aromatse gene expression and 17-beta estradiol concentration]

Previous studies have investigated the effects and importance of orexin and estradiol on food intake. In this study the effects of orexin on estradiol release by the ventromedial hypothalamus [satiety center] and lateral hypothalamus [feeding center] have been investigated. Forty adult male rats, divided to two groups, the control group [consisting of 10 rats] and an experimental group [consisting of 30 rats], were canulated in the lateral area and ventromedial nucleus steriotaxically. After two days recovery, 1, 2 and 4 micrograms of orexin were injected into the lateral area and ventromedial nucleus. After two hours, tissue of the lateral area and ventromedial nucleus were removed and concentrations of estradiol and aromatase were measured by radio-immuno assay and RT-PCR, respectively. Results of RT-PCR showed that orexin-A [1, 2, 4 microg] augmented aromatase gene expression in the VMH and LH.17-beta estradiol measurement showed that 1, 2 and 4 microg orexin infusion increased estradiol levels significantly in VMH and LH, especially the 2 and 4 microg doses, observations suggesting that the neurons secreting estradiol exist in the VMH and LH

[Effect of stress induced by epinephrine and cortisol injection on orexin secretion in male rats fed with different levels of their energy requirement]

Orexin is a potent orexigenic agent in rodents and humans. Some research shows that orexin participates in the adaptive response to weight loss and its levels rise with dieting. On the other hand, weight loss and fasting is accompanied by increased levels of epinephrine and cortisol. In this study we investigated the effects of epinephrine [EN] and cortisol on fastinginduced orexin secretion in rats fed different levels of their energy requirements. Forty-five male wistar rats [300-350 g, 15 per group] were fed a diet containing 100%, 50% and 25% of their energy requirement for 10 days, rats were anesthetized following 48 hour prolonged fasting and then cannulated in the carotid artery for drug injection and blood sampling. Animals were divided into 3 treatment groups that received either [3 micro g/Kg BW] EN, cortisol or a combination of those two [0.1 mg in 1 ml of PBS]. Orexin and glucose levels were analyzed before [time 0], and 30, 60 and 120 min after injection. In the 50% and 100% food restricted groups, fasting orexin levels fell after EN and the combination of EN and cortisol injection respectively [p o.o5]. These results indicate that injection of EN suppresses starvation-induced secretion of orexin in normal [100%] and starved [50%] rats, and that orexin secretion response to EN might be affected by weight loss.

[Effects of testosterone and growth hormone on plasma concentrations of orexin in diet restricted rams]

It has been established that multiple neuroendocrine factors such as orexin operate as metabolic signals for the reproductive tract. Since the effects of testosterone and growth hormone on concentration of orexin in rams have not been studied, the goal of this study was to determine the effect of testosterone and growth hormone on mean plasma concentrations of orexin in rams fed restricted diets. Rams were randomly divided into 2 groups. Animals in first group were fed 100% of their required daily food and those in the second group were fed 50% of food fed to the first group for 10 days. Consequently, the rams in all groups received 6microg /Kg BW testosterone on days 7 and 8 and 6microg /Kg BW Testosterone and 5 microg /Kg BW growth hormone on days 9 and 10 of the experiment. Blood samples were collected from the jugular veins at -120 and +120 minutes of infusions. for orexin assay, Plasma orexin were measured by a homologous double-antibody radioimmunoassay [RIA]. Injection of different dosages of testosterone and combination of testosterone and growth hormone in the 50%-diet, significantly [P<0.05*] increased the mean plasma concentrations of orexin, while in the 100%-diet this had no effect. Results indicate that testosterone and growth hormone may increase mean concentrations of orexin in animals fed lower than their daily food requirement

effects of interaction between ghrelin and substance-P on mean plasma thyroid hormones concentration and body weight

Ghrelin increases food intakes and body weight via growth hormone secretagogues receptor [GHSR-Ia]. [D-Arg-1, D-phe-5, D-Trp-7, 9, Leu-11] Substance-P [an analog of Substance-P] is known as an antagonist of GHSR-Ia receptor which inhibits ghrelin- induced food intakes. Thyroid hormones have also an important role in the regulation of metabolism and body weight. The goal of this study was to determine the effect of different doses of either ghrelin, analog of Substance-P or their interactions on the body weight, mean plasma TSH, Triiodothyronine [T3] and Thyroxine [T4] concentration and to investigate whether ghrelin exerts its effects on thyroid axis activity via GHSR-Ia. Rats received different doses of ghrelin [1, 5, or 10 nmol], analog of Substance P [5, 10, 20 nmol] or saline via lateral cerebral ventricle. Body weight was measured daily before injection and at 9 h of the day after the final injection. The blood samples were collected at the end of experiment. Plasma was assayed for thyroid hormones concentration. Ghrelin significantly increased body weight and decreased mean plasma TSH, T3 and T4 concentrations in a dose related manner. Analog of Substance-P significantly decreased body weight and increased thyroid hormones concentration in a dose related manner. It blocked the stimulatory effect of ghrelin on body weight and the inhibitory effect of ghrelin on thyroid axis activity. From the results of this study it appears that analog of substance P may be useful for treatment of obesity

Changes in the plasma concentrations of thyroid hormones in ewes and the effect of intravenous injection of leptin on their levels

The aim of this study was to determine changes in the concentration of leptin and thyroid hormone in energyrestricted ewes and effect of leptin injection on thyroid hormone level. In the first experiment, 28 ewes were assigned to two groups [n = 14]. Ewes were fed by a ration that provided 60% or 100% of maintenance energy requirements during 71 days. Blood samples were collected and body weight [BW] and body condition score [BCS] were determined. In the second experiment, 6 energy-restricted ewes from the first experiment were selected and assigned to two groups [n = 3]. Ewes were fed a ration that provided 60% of maintenance energy requirements and injected by 1 or 4 micro leptin/Kg BW. Blood samples were taken and BW and BCS were determined. In the first experiment, concentrations of leptin, T[3] and T[4], BW and BCS were decreased in energyrestricted ewes [p < 0.01]. In the second experiment, concentration of T[3], T[4] and leptin were increased by leptin injection [p < 0.01]. The results suggested leptin injection may restore thyroid hormone secretion to normal levels in energy-restricted ewes

[ effect of L-tryptophan on growth hormone and thyroid hormones secretion in growing lambs]

Survey on effects of serotonin agonist on the plasma concentrations of growth hormone [GH] and thyroid hormones [T[3] and T[4]; TH]. Repeated measures [GLM] were used. Twenty Kurdish lambs 3-4 months old. Animals were randomly divided into four groups. The first group [control] received 2 ml normal saline. The second, third and fourth groups received 120, 240 and 480 mg/kg body weight L-tryptophan through jugular vein, respectively. blood samples were collected in three periods including before [days 1, 4, 5 and 6], during [days 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 22, 26, 30 and 34] and after [days 36, 37 and 38] injections. Plasma concentrations of these hormones in unextracted samples were analyzed by radioimmunoassay kit [Tabeshyarnoor kits company, Tehran, Iran]. Injection of serotonin agonist increased mean plasma concentration [MPC] of GH [P<0.01]. There are no significant differences in MPC of GH within the treated groups. Effects of blood sampling times, period [before, during, after injection] and their interaction with treatment on MPC of GH were significant[ P<0.01]. MPC of TH [T[3] and T[4]] in all of the treated groups was significantly increased compare with control one [P<0.01]. There are no significant differences in MPC of TH within the treated groups. Effects of blood sampling times and period [before, during and after injection] and also their interactive effects with treatment were significant. According to statistical analysis of data we can suggest that serotonin agonist stimulates GH and TH secretion simultaneously

Epidemiological study of T4, T3 and TSH mean concentrations in four Iranian populations

T4 and T3, two major hormones of thyroid gland, are responsible for regulation of "basal metabolism" in the body. Thyroid function is regulated primarily by variation in the pituitary TSH. In this study, about four hundred individuals were considered from four Iranian populations. They were selected randomly in their cities; Shiraz, Mashhad, Rasht, and Ilam. Essential family information was asked to achieve native belonging of each person to related population. Blood specimens were collected, by separating serums, freezed serums were transferred immediately to Tehran for hormone assay. Assay of T4 and T3 concentrations was carried out by 'RIA-magnetic' kits and of TSH by 'IRMA-magnetic' kits. Analysis of variance has been taken into account among days of sampling in each city to calculate mean concentrations for T4, T3 and TSH. Analysis of association between age and hormones concentrations in each population was done by the regression and the correlation tests. Significant differences were detected at T4 mean concentration in each of these populations [P=0.0001]. Differences for T3 mean concentration were observed only between Shiraz and Mashhad [P=0.021]; and Shiraz and Rasht [P=0.003]. By increasing age of individuals, there were also a negative correlation at mean concentrations of T4 and T3 in Ilam [P=0.022], and Mashhad [P=0.016] respectively. According to these data, and specificity of environmental and genetic factors to each popualtions, specific 'normal reference' of T4 and T3 homones should be considred for each of these populations. Correlation study of mean concentrations of these hormones and genetic variations of some critical genes such as thyroid peroxidase [TPO] and iodothyronine deiodinase can open new window of epidimiology among Iranian popualltions

[ Effect of successive injections of naloxone on gonadotrophins secretion in ewe in nonbreeding season]

Objective: Determination of the Naloxone opioid antagonist effect on the LH and FSH secretion in ewe in non-breeding season

Design: Repeted measures

Animals: Six zandi breed ewes with average [ +/- SE] of weight and age, 42.4 ±4.2 and 760±8 respectively and all of ewes had one birth

Procedure: Ewes were recieved five injections of 0.5 or 0.2 mg naloxone/kg BW and followed by injection of 1 1 g gonadorelin /kg BW. Blood samples were collected every 15 minutes for 4 hours before injections until 4 hours after injections of naloxone and every 15 minutes for 1 hours after injection of gonadroline

Statistical analysis: Analysis of variation

Results: Mean plasma LH concentrations had been significantly increased in both groups after naloxone injections. LH pulses frequencies in both groups significantly increased after naloxone injections. Naloxone failed to alter pulsatile LH amplitudes in both groups. LH base concentrations increased in both groups after injections of naloxone but it was not significant. Also mean plasma LH concentrations had been significantly increased after gonadorelin injection. Mean plasma FSH concentrations, pulsatile frequencies, amplitudes and base concentrations of FSH did not change significantly

Clinical Implications: The results of this study indicate that the opioids may affect on LH pattern secretion in the ewes in nonbreeding season, but the effect of opioid on FSH secretion is not observed