Increased Serum Growth Hormone Research Articles

GH and IGF-1 in skin interstitial fluid and blood are associated with heat loss responses in exercising young adults.

Sweat glands and cutaneous vessels possess growth hormone (GH) and insulin-like growth factor 1 (IGF-1) receptors. Here, we assessed if exercise increases GH and IGF-1 in skin interstitial fluid, and whether baseline and exercise-induced increases in GH and IGF-1 concentrations in skin interstitial fluid/blood are associated with heat loss responses of sweating and cutaneous vasodilation. Sixteen young adults (7 women) performed a 50-min moderate-intensity exercise bout (50% VO2peak) during which skin dialysate and blood samples were collected. In a sub-study (n = 7, 4 women), we administered varying concentrations of GH (0.025-4000ng/mL) and IGF-1 (0.000256-100µg/mL) into skin interstitial fluid via intradermal microdialysis. Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC) were measured continuously for both studies. Exercise increased sweating and CVC (both P < 0.001), paralleled by increases of serum GH and skin dialysate GH and IGF-1 (all P ≤ 0.041) without changes in serum IGF-1. Sweating was positively correlated with baseline dialysate and serum GH levels, as well as exercise-induced increases in serum GH and IGF-1 (all P ≤ 0.044). Increases in CVC were not correlated with any GH and IGF-1 variables. Exogenous administration of GH and IGF-1 did not modulate resting sweat rate and CVC. (1) Exercise increases GH and IGF-1 levels in the skin interstitial fluid, (2) exercise-induced sweating is associated with baseline GH in skin interstitial fluid and blood, as well as exercise-induced increases in blood GH and IGF-1, and (3) cutaneous vasodilation during exercise is not associated with GH and IGF-1 in skin interstitial fluid and blood.

Effects of glycyrrhiza polysaccharides on growth performance, meat quality, serum parameters and growth/meat quality-related gene expression in broilers.

With growing restrictions on the use of antibiotics in animal feed, plant extracts are increasingly favored as natural feed additive sources. Glycyrrhiza polysaccharide (GP), known for its multifaceted biological benefits including growth promotion, immune enhancement, and antioxidative properties, has been the focus of recent studies. Yet, the effects and mechanisms of GP on broiler growth and meat quality remain to be fully elucidated. This study aimed to investigate the effects of GP on growth, serum biochemistry, meat quality, and gene expression in broilers. The broilers were divided into five groups, each consisting of five replicates with six birds. These groups were supplemented with 0, 500, 1,000, 1,500, and 2,000 mg/kg of GP in their basal diets, respectively, for a period of 42 days. The results indicated that from day 22 to day 42, and throughout the entire experimental period from day 1 to day 42, the groups receiving 1,000 and 1,500 mg/kg of GP showed a significant reduction in the feed-to-gain ratio (F:G) compared to the control group. On day 42, an increase in serum growth hormone (GH) levels was shown in groups supplemented with 1,000 mg/kg GP or higher, along with a significant linear increase in insulin-like growth factor-1 (IGF-1) concentration. Additionally, significant upregulation of GH and IGF-1 mRNA expression levels was noted in the 1,000 and 1,500 mg/kg GP groups. Furthermore, GP significantly elevated serum concentrations of alkaline phosphatase (AKP) and globulin (GLB) while reducing blood urea nitrogen (BUN) levels. In terms of meat quality, the 1,500 and 2,000 mg/kg GP groups significantly increased fiber density in pectoral muscles and reduced thiobarbituric acid (TBA) content. GP also significantly decreased cooking loss rate in both pectoral and leg muscles and the drip loss rate in leg muscles. It increased levels of linoleic acid and oleic acid, while decreasing concentrations of stearic acid, myristic acid, and docosahexaenoic acid. Finally, the study demonstrated that the 1,500 mg/kg GP group significantly enhanced the expression of myogenin (MyoG) and myogenic differentiation (MyoD) mRNA in leg muscles. Overall, the study determined that the optimal dosage of GP in broiler feed is 1,500 mg/kg.

Evaluation of Spray-Dried Bovine Hemoglobin Powder as a Dietary Animal Protein Source in Nile Tilapia, Oreochromis niloticus.

The present study evaluated the potential effects of dietary inclusion of spray-dried bovine hemoglobin powder (SDBH) on the growth, gene expression of peptide and amino acid transporters, insulin growth factor-1 (IGF-1) and myostatin, digestive enzymes activity, intestinal histomorphology and immune status, immune-related gene expression, and economic efficiency in Nile tilapia, Oreochromis niloticus. Two hundred twenty-five fingerlings (32.38 ± 0.05 g/fish) were distributed into five treatments with five dietary inclusion levels of SDBH: 0, 2.5, 5, 7.5, and 10% for a ten-week feeding period. Dietary inclusion of SDBH linearly increased the final body weight (FBW), total weight gain (TWG), specific growth rate (SGR), and protein efficiency ratio (PER). Additionally, a linear decrease in feed conversion ratio (FCR) and daily feed intake relative to the daily BW was reported in the highest inclusion levels (7.5 and 10%). Dietary inclusion of SDBH was associated with a significant increase in the intestinal villous height (VH), villous width (VW), villous height: crypt depth ratio (VH: CD), and muscle coat thickness (MCT), with the highest values reported in SDBH7.5 group. Increased serum growth hormone levels and decreased serum leptin hormone levels were also reported by increasing the SDBH level. The serum glucose level was decreased in the SDBH7.5 and SDBH10 groups. The digestive enzymes' activity (amylase and protease) was increased by increasing the SDBH inclusion level. An up-regulation in the expression of peptide and amino acid transporters, IGF-1, and down-regulation of myostatin was reported in the SDBH2.5 to SDBH7.5 groups. Spleen sections showed more lymphoid elements, especially in the SDBH2.5 and SDBH7.5 groups. The SDBH inclusion increased the serum lysozyme activity, nitric oxide (NO), and complement 3 (C3) levels, with the highest values recorded in the SDBH5 group. The phagocytic % and the phagocytic index were increased by increasing the SDBH inclusion %. The expressions of immune-related genes (transforming growth factor-beta (TGF-β), Toll-like receptor 2 (TLR2), and interleukin 10 (IL10)) were up-regulated by SDBH inclusion with the highest expression in the SDBH5 group. Economically, the feed costs and feed costs/kg gain were linearly decreased in the SDBH7.5 and SDBH10 diets. In conclusion, spray-dried bovine hemoglobin powder could be used as a protein source for up to 10% of the diets of Nile tilapia for better growth and immune status of fish.

Growth hormone modulates Trypanosoma cruzi infection in vitro

ObjectiveChagas disease (CD) is caused by the protozoan parasite, Trypanosoma cruzi. It affects 7 to 8 million people worldwide and leads to approximately 50,000 deaths per year. In vitro and in vivo studies had demonstrated that Trypanosoma cruziinfection causes an imbalance in the hypothalamic-pituitary-adrenal (HPA) axis that is accompanied by a progressive decrease in growth hormone (GH) and prolactin (PRL) production. In humans, inactivating mutations in the GH receptor gene cause Laron Syndrome (LS), an autosomal recessive disorder. Affected subjects are short, have increased adiposity, decreased insulin-like growth factor-I (IGFI), increased serum GH levels, are highly resistant to diabetes and cancer, and display slow cognitive decline. In addition, CD incidence in these individuals is diminished despite living in highly endemic areas. Consequently, we decided to investigate the in vitro effect of GH/IGF-I on T. cruzi infection. DesignWe first treated the parasite and/or host cells with different peptide hormones including GH, IGFI, and PRL. Then, we treated cells using different combinations of GH/IGF-I attempting to mimic the GH/IGF-I serum levels observed in LS subjects. ResultsWe found that exogenous GH confers protection against T. cruzi infection. Moreover, this effect is mediated by GH and not IGFI. The combination of relatively high GH (50 ng/ml) and low IGF-I (20 ng/ml), mimicking the hormonal pattern seen in LS individuals, consistently decreased T. cruzi infection in vitro. ConclusionsThe combination of relatively high GH and low IGF-I serum levels in LS individuals may be an underlying condition providing partial protection against T. cruzi infection.

Effect of Dietary Betaine on Muscle Protein Deposition, Nucleic Acid and Amino Acid Contents, and Proteomes of Broilers.

Simple SummaryIn animal production, growth trials have shown that betaine has a positive effect on growth performance, especially improving meat yield. Proteins are the largest unit comprising muscle cells except moisture. However, how betaine regulates muscle protein anabolism and abundance levels remains unclear. Therefore, this study was conducted to investigate the effect of dietary betaine on growth performance, muscle protein deposition, and proteome of broilers. The results suggested that betaine could improve growth performance and muscle protein deposition of broilers. Alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process. Proteomic analysis further revealed that 35 proteins in breast muscle were identified as differentially abundant proteins by betaine supplementation, which were mainly related to cell differentiation, small molecule metabolic process, and tissue development.To investigate the effect of betaine supplementation on growth performance, muscle protein deposition, muscle nucleic acid and amino acid contents, and muscle proteome of broilers, 160 one-day-old male partridge shank broiler chickens were randomly divided into 2 groups with 8 replicates of 10 broilers each. Broilers were fed a basal diet alone, or a basal diet supplemented with 1000 mg/kg betaine. Compared with the control group, the betaine group significantly increased (p < 0.05) the broilers average daily gain, the levels of serum insulin-like growth factor-1 (IGF-1), growth hormone (GH), total protein (TP), the contents of muscle absolute protein deposition, RNA, Ser, Glu, Met, and Phe, and the ratio of RNA/DNA, and decreased (p < 0.05) the feed conversion ratio and serum blood urea nitrogen content. Moreover, proteomic analysis revealed 35 differentially abundant proteins (DAPs) in the betaine group compared with the control group, including 27 upregulated proteins and 8 downregulated proteins (p < 0.05). These DAPs were mainly related to cell differentiation, small molecule metabolic process, and tissue development. In conclusion, diets supplemented with 1000 mg/kg betaine improved growth performance and muscle protein deposition of broilers. Increased serum GH, IGF-1, and TP contents, and alterations in muscle nucleic acids, amino acids, and protein abundance levels were involved in this process.

Ethanolic Extract of Pluchea indica Less leaf Increases Serum Growth Hormone in Lactating Rats

The objectives of the study were to evaluate the effect of ethanolic extract of P. indica Less leaf (EPI) on serum growth hormone (GH), milk yield, body weight gain of dams, and dam’s organ weight in lactating rats. A total of 25 lactating rats with six pups were randomized and distributed to one of five treatments (control (RO water), standard (domperidone 2,5 mg/kg BW/day), EPI 250 (250 mg/kg BW of EPI), EPI 500 (500 mg/kg BW of EPI), and EPI 750 (750 mg/kg BW of EPI)). The treatment was administered daily starting from the 2nd until the 15th day of lactation. On the 16th day serum growth hormone level, body and organ weight of rats were measured. Serum GH levels in the EPI 750 group (1963.25 ± 360.91 pg/µL) increased significantly compared to the domperidone (409.46 ± 28.80 pg/µL) and the control group (723.40 ± 95.78 pg/µL, p0.05). There was significant body weight gain in the EPI 750 group compared with the domperidone group. There was no significant difference in organ weight gain in each group. The study revealed that ethanolic extract of P. indica Less leaf can increase serum growth hormone in lactating rats.

Effects Of Aqueous Extract Of Momordica Balsamina L. On Milk Yield, Lactogenic Hormones And Biomarkers Of Oxidative Stress In Lactating Wistar Rats

Background: Momordica balsamina L. is a medicinal plant used in traditional medicine to stimulate milk production. The study was designed to evaluate the effect of aqueous extract of Momordica balsamina L. on milk yield, serum lactogenic hormones and biomarkers of oxidative stress in lactating. Material and methods: Twenty five female lactating Wistar rats (n = 25) with 4 pups each were divided into five (5) groups of five (5) rats each and treated as follows: Group I: 1ml/kg distilled water; group II: 5 mg/kg metoclopramide; group III: 200 mg/kg; group IV: 400 mg/kg and group V: 800 mg/kg of Momordica balsamina L., respectively. Administration was done orally once daily at 18:00 hr for a period of 10 days, during which the milk yield was calculated daily at 18 hr after gavage. At the end of the experiment, the Wistar rats were sacrificed and blood samples and mammary tissue were harvested for analysis of prolactin, growth hormone and biomarkers of oxidative stress and histological studies. Results: There was a significantly lower serum prolactin level (p&lt; 0.05) in the 800 mg/kg treated group when compared to the control. Serum growth hormone level was significantly higher in all the treated as compared with the control group (p&lt; 0.05). Momordica balsamina L. stimulated a significant increase (p&lt; 0.05) in milk yield at 400 mg/kg when compared to the control group. It also caused a significantly lower (p &lt; 0.05) serum activity of superoxide dismutase in the 400 mg/kg and 800 mg/kg groups compared to the control group. While, serum glutathione peroxidase and catalase were significantly lower (p&lt; 0.05) in the 800 mg/kg treated groups, when compared to the control group. Significantly higher (p&lt; 0.05) serum Melondialdehyde levels were observed in the treated compared to the control. The mammary glands of rats treated with the extract showed lobuloalveolar development at 400 mg/kg. Conclusion: The study highlighted that Momordica balsamina L. stimulates mean milk yield, increase serum growth hormone and enhance lobuloaveolar development.

Puerarin improved growth performance and postmortem meat quality by regulating lipid metabolism of cattle under hot environment.

This study aims to evaluate the effect of puerarin on performance, meat quality, and serum indexes of beef cattle under hot environment. Thirty-two bulls were divided into four groups and fed diet supplemented with puerarin at 0, 200, 400, or 800mg/kg. Results showed that heat stress was employed for 54 out of 60days, 400mg/kg group declined serum cortisol (COR) contents, all treatments increased the contents of total cholesterol, high density lipoprotein cholesterol, and total superoxide dismutase activity; in addition, glutathione peroxidase activity of 200mg/kg group were enhanced, only 800mg/kg group enhanced immunoglobulin (IgA, IgM, and IgG) and low density lipoprotein cholesterol contents compared with the control (p<.05). Moreover, 400-mg/kg puerarin increased serum growth hormone levels compared with 200mg/kg group but declined COR concentrations compared with 200mg/kg and 800mg/kg groups (p<.05). More importantly, average daily gain anddaily matter intake, and intramuscular fat contents of 400mg/kg group were enhanced, but the shear force of beef in 400mg/kg and 800mg/kg groups were declined compared with the control (p<.05). These findings indicated that supplemental with puerarin enhanced immune and antioxidant, and 400mg/kg of puerarin improved performance and meat quality by normalizing levels of stress hormones and increasing intramuscular fat deposition of beef cattle under hot environment.

Sex differences in somatotrope response to fasting: biphasic responses in male mice.

Anterior pituitary somatotropes are important metabolic sensors responding to leptin by secreting growth hormone (GH). However, reduced leptin signals caused by fasting have not always correlated with reduced serum GH. Reports show that fasting may stimulate or reduce GH secretion, depending on the species. Mechanisms underlying these distinct somatotrope responses to fasting remain unknown. To define the somatotrope response to decreased leptin signaling we examined markers of somatotrope function over different time periods of fasting. Male mice were fasted for 24 and 48 h, with female mice fasted for 24 h compared to fed controls ad libitum. Body weight and serum glucose were reduced in both males and females, but, unexpectedly, serum leptin was reduced only in males. Furthermore, in males, serum GH levels showed a biphasic response with significant reductions at 24 h followed by a significant rise at 48 h, which coincided with the rise in serum ghrelin levels. In contrast, females showed an increase in serum GH at 24 h. We then explored mechanisms underlying the differential somatotrope responses seen in males and observed that pituitary levels of Gh mRNA increased, with no distinction between acute and prolonged fasting. By contrast, the Ghrhr mRNA (encoding GH releasing hormone receptor) and the Ghsr mRNA (encoding the ghrelin receptor) were both greatly increased at prolonged fasting times coincident with increased serum GH. These findings show sex differences in the somatotrope and adipocyte responses to fasting and support an adaptive role for somatotropes in males in response to multiple metabolic signals.

Increased serum nesfatin-1 levels in patients with acromegaly.

Nesfatin-1 was identified as a satiety factor involved in the regulation of metabolism. Altered levels of circulating nesfatin-1 had been observed in a variety of diseases characterized by energy imbalance. However, there was no published data about nesfatin-1 levels in acromegaly.We evaluated serum nesfatin-1 levels in 13 patients with acromegaly at baseline and postoperatively, and in 21 age- and body mass index (BMI)-matched healthy subjects.Compared with the healthy subjects, patients with acromegaly had significantly increased levels of serum insulin, high-density lipoprotein cholesterol, triglyceride, and growth hormone (GH). Moreover, the acromegaly group had nesfatin-1 levels higher than controls (1.96 ± 0.56 ng/mL vs 0.61 ± 0.10 ng/mL, P = .004). There was a positive correlation of serum nesfatin-1 levels with diastolic blood pressure (r = 0.579, P = .038) and homeostasis model assessment of insulin resistance (HOMA-IR) (r = 0.598, P = .031) in patients with acromegaly. While a successful surgery decreased serum GH levels, the serum nesfatin-1 levels did not change in acromegaly (P = .965). At last, we compared serum GH/nesfatin-1 levels with predictive markers for aggressive behaviors in pituitary adenomas. There was no relationship between serum nesfatin-1 levels and tumor's size, Ki-67 index, mutant p53, or MGMT proteins. However, increased serum GH levels were positively correlated with tumors’ size (P = .023) and mutant p53 proteins expression (P = .028).Circulating nesfatin-1 was increased in acromegaly, which was involved in metabolism regulation.

Peptides from Euphausia superba Promote Longitudinal Bone Growth by Accelerating Growth Plate Chondrocyte Proliferation and Hypertrophy.

With the improvements in living standards, height is getting more attention. Malnutrition is one of the main causes of children's short stature; therefore, nutritional intervention in adolescence is the key to prevent short stature. The peptides from Antarctic Krill (AKPs), the ideal protein model, act in bone formation and anti-osteoporosis. However, the studies on promoting longitudinal bone growth by AKPs have not been reported. Three-week-old male ICR mice, to construct the adolescent mice model, randomly divided into three groups: normal group, casein group (casein, 300 mg/kg·BW), and AKPs group (AKPs, 300 mg/kg·BW). After 21 days of drug administration, the effects of AKPs on serum biochemical indexes and femur histomorphology of mice, and the mechanism of AKPs promoting longitudinal bone growth was discussed. AKPs significantly increased longitudinal bone growth and improved bone strength. In addition, AKPs remarkably promoted proliferation and hypertrophy of chondrocytes in the growth plate. The further mechanism revealed that AKPs increased serum Growth Hormone (GH) and Insulin-Like Growth Factors-1(IGF-1) contents, which activated the downstream GH/IGF-1 axis signaling pathways. Moreover, AKPs induced the secretion and expression of bone morphogenetic protein 2 (BMP- 2) and triggered the activation of BMP2-dependent Smads signaling. AKPs also activated Wnt/ β-catenin signaling, and synergistically activated the expression of Runt-related transcription factor 2 (Runx 2) and Osterix (OSX). AKPs promoted longitudinal bone growth by activating GH/IGF-1 axis, BMP-2/Smads and Wnt/β-catenin pathways, suggesting AKPs to be a potential nutrient fortifier for longitudinal bone growth.

Effects of coated cysteamine on growth performance, carcass characteristics, meat quality and lipid metabolism in finishing pigs

This study was conducted to evaluate the effects of coated cysteamine (CCS) on growth performance, carcass characteristics, meat quality, and lipid metabolism in finishing pigs. A total of 160 pigs (62.12 ± 1.43 kg body weight) were randomly divided into 4 groups, with 4 pens per group and 10 pigs (5 gilts and 5 barrows) per pen. Pigs were fed a basal diet supplemented with 0, 100, 200, or 400 mg/kg CCS, corresponding to 0, 27, 54, or 108 mg/kg cysteamine, respectively. All pigs were given free access to feed and water for forty days. Average daily gain, average daily feed intake and feed to gain ratio were not affected by the CCS treatment. Supplemental CCS increased carcass lean ratio linearly (P < 0.05) and longissmus muscle area quadratically (P < 0.05), and the water-holding capacity as measured by 24 h drip loss was quadratically affected (P < 0.05) by CCS supplementation. The activity of hormone-sensitive lipase in subcutaneous adipose tissue was linearly increased (P < 0.001), while fatty acid synthase activity was linearly decreased (P < 0.05). Pigs fed CCS had a lower serum triacylglycerol (P < 0.001) level and lipase activity (P < 0.001), lower total cholesterol (P < 0.05) level, and a higher total protein (P < 0.001) and free fatty acids (P < 0.01) levels. In addition, CCS quadratically increased serum growth hormone (GH) (P < 0.001) level and quadratically affected somatostatin (SS) (P < 0.05) level. Consistently, significant effects of dietary CCS were observed on the mRNA expression of GH and SS in the anterior pituitary gland and the hypothalamus, respectively, where the intermediate CCS level showed the highest GH mRNA level and lowest SS mRNA level. The results indicate that dietary supplementation of CCS has beneficial effects on carcass characteristics and meat quality, and affects lipid metabolism in finishing pigs.

Resistance exercise causes greater serum hepcidin elevation than endurance (cycling) exercise.

BackgroundHepcidin is an iron regulating hormone, and exercise-induced hepcidin elevation is suggested to increase the risk of iron deficiency among athletes.ObjectiveWe compared serum hepcidin responses to resistance exercise and endurance (cycling) exercise.MethodsTen males [mean ± standard error: 172 ± 2 cm, body weight: 70 ± 2 kg] performed three trials: a resistance exercise trial (RE), an endurance exercise trial (END), and a rest trial (REST). The RE consisted of 60 min of resistance exercise (3−5 sets × 12 repetitions, 8 exercises) at 65% of one repetition maximum, while 60 min of cycling exercise at 65% of was performed in the END. Blood samples were collected before exercise and during a 6-h post-exercise (0h, 1h, 2h, 3h, 6h after exercise).ResultsBoth RE and END significantly increased blood lactate levels, with significantly higher in the RE (P < 0.001). Serum iron levels were significantly elevated immediately after exercise (P < 0.001), with no significant difference between RE and END. Both the RE and END significantly increased serum growth hormone (GH), cortisol, and myoglobin levels (P < 0.01). However, exercise-induced elevations of GH and cortisol were significantly greater in the RE (trial × time: P < 0.001). Plasma interleukin-6 (IL-6) levels were significantly elevated after exercise (P = 0.003), with no significant difference between the trials. Plasma hepcidin levels were elevated after exercise (P < 0.001), with significantly greater in the RE (463 ± 125%) than in the END (137 ± 27%, P = 0.03). During the REST, serum hepcidin and plasma IL-6 levels did not change significantly.ConclusionResistance exercise caused a greater exercise-induced elevation in hepcidin than did endurance (cycling) exercise. The present findings indicate that caution will be required to avoid iron deficiency even among athletes in strength (power) types of events who are regularly involved in resistance exercise.

MON-482 Sex-Dependent Biphasic Response by Somatotropes to Fasting and Loss of Leptin Signaling

Fasting results in a well-established rise in serum growth hormone (GH) in mice and humans. In mice, this coincides with increases in Gh and growth hormone releasing hormone receptor (Ghrhr) mRNA, as well as serum ghrelin. However, fasting also results in a dramatic decline in serum leptin and we have shown that pituitary somatotropes are dependent on circulating leptin to maintain sufficient stores of GH and GHRHR proteins. This study was designed to determine the mechanisms by which GH increases in the presence of reduced serum leptin in fasted mice. We hypothesized that the rise in GH was due to ghrelin-stimulated pathways and therefore developed a fasting model to test this. However, a review of the literature revealed a study by Steyn et al. (2011) that demonstrated an acute decline in GH pulses in male mice after 12-18 hours of fasting, which suggest that somatotropes may display a biphasic response to fasting, with the early or acute phase driven by the absence of leptin signals. We tested this hypothesis in 3 groups of male and female mice: group 1 was fasted for 24 hours; group 2 was also fasted for 24 hours and received 10% glucose water, which is known to normalize serum leptin; and group 3 mice were fed ad libitum. Following a 24 h fast, leptin levels declined significantly from 5.5±2 ng/ml to 0.37±0.1 ng/ml (Student’s t; p=0.01) along with significant decreases in body weight, serum glucose and insulin. Fasted mice receiving glucose water showed a significant recovery in leptin to 6.9±2.7 ng/ml (Student’s t; p=0.03 n=8) along with a recovery in serum glucose and insulin. In agreement with Steyn et al. (2011), serum GH in male mice showed a significant decline from 10.7±3 ng/ml (fed) to 3±0.6 ng/ml after the 24 h fast (p=0.04 ANOVA). Glucose water and the recovery in serum glucose, leptin and insulin were unable to normalize GH levels in fasted male. In contrast, fasted female mice had a 2.2 fold (p= 0.0427) increase in serum GH and no change with glucose water. There was a significant increase in pituitary Ghrhr and Gh mRNA in fasted male mice but not in fasted female mice. Assays of serum or mRNA levels of most pituitary hormones showed no significant changes following a 24 h fast. These studies have thus uncovered an acute response to fasting by GH cells in male mice, which correlates to reduced serum GH resulting from a loss of leptin signals. The data extends findings reported previously showing that male somatotropes are more dependent on leptin signals than female somatotropes. Whereas the high Gh and Ghrhr mRNA support somatotrope stimulation, the somatotropes are unable to secrete normal levels of GH in the male, suggesting defects at the level of GH or GHRHR protein expression.

Effects of rumen-protected folic acid and branched-chain volatile fatty acids supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows

This study evaluated the effects of branched-chain volatile fatty acids (BCVFA) and rumen protected folic acid (RPFA) supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows. Fifty-six multiparous Chinese Holstein cows (3.2 ± 1.1 of parity, 631 ± 16.4 kg of body weight [BW], 65 ± 2.6 days in milk [DIM] and 30.2 ± 2.1 kg of milk yield per day, mean ± SD) were blocked by lactation number, milk yield per day and DIM and were arranged into one of four groups in a randomized block design with a 2 × 2 factorial arrangement. Supplemental BCVFA (0 g/d [BCVFA-] or 80 g/d [BCVFA+]) and RPFA (0 mg/d [RPFA-] or 128 mg/d [RPFA+]) were hand-mixed into the top one-third of total mixed ration. Dietary concentrate to forage ratio was 50:50 based on a dry matter (DM) basis. Experimental periods comprised 105 days with 15 d of adaptation followed by 90 d of data collection. DM intake was increased with BCVFA supplementation, but was unaffected by RPFA. The BW changes were similar among treatments. Yields of milk, milk fat and lactose were increased, and milk true protein yield tended to increase with BCVFA or RPFA supplementation. Milk fat percentage was increased with BCVFA supplementation, but was unaffected by RPFA. Percentage of milk true protein was increased, lactose was unaltered and feed conversion ratio was decreased with BCVFA or RPFA supplementation. Ruminal pH and ammonia N concentration were decreased, but total volatile fatty acids concentration was increased with BCVFA or RPFA supplementation. Molar proportion of acetate was increased and propionate was decreased, resulting in an increased ratio of acetate to propionate with BCVFA supplementation. Acetate and propionate molar proportion and the ratio of acetate to propionate were not affected by RPFA. Digestibilities of DM, organic matter, crude protein, non-fiber carbohydrates, neutral detergent fibre and acid detergent fibre were increased with BCVFA or RPFA supplementation. Similarly, activities of caboxymethyl-cellulase, cellobiase, xylanase, pectinase, α-amylase and protease and abundance of R. albus, R. flavefaciens, F. succinogenes, B. fibrisolvens and P. ruminicola were increased. However, R. amylophilus abundance was not affected by BCVFA and increased with RPFA supplementation. Serum concentrations of glucose and non-esterified fatty acids (NEFA) were unaltered and total protein was increased with BCVFA or RPFA supplementation. Serum acetoacetate (ACAC) and BHBA were increased by BCVFA, but were decreased by RPFA. Supplementation of BCVFA or RPFA increased serum growth hormone releasing hormone, growth hormone and insulin-like growth factor-1. These results indicated that lactation performance, ruminal fermentation, nutrient digestion and hormone secretion improved due to the stimulated ruminal bacteria growth and enzyme activity with BCVFA or RPFA supplementation, but no BCVFA × RPFA interaction was detected during the trial.

Neuromuscular electrical stimulation with blood flow restriction increases serum growth hormone concentration

Neuromuscular electrical stimulation with blood flow restriction increases serum growth hormone concentration

Metabolic and Performance Responses to Sprint Exercise under Hypoxia among Female Athletes

The present study determined metabolic and performance responses to repeated sprint exercise under hypoxia among female team-sport athletes. Fifteen female athletes (age, 20.7±0.2 years; height, 159.6±1.7 cm; body weight, 55.3±1.4 kg) performed two exercise trials under either a hypoxic [HYPO; fraction of inspired oxygen (F i O 2 ), 14.5%] or normoxic (NOR; F i O 2 , 20.9%) condition. The exercise consisted of two sets of 8×6-s maximal sprint (pedaling). The average power output was not significantly different between trials for set 1 ( P =0.89), but tended to be higher in the NOR trial for set 2 ( P =0.05). The post-exercise blood lactate concentrations were significantly higher in the HYPO trial than that in the NOR trial ( P <0.05). Exercise significantly increased serum growth hormone (GH) and cortisol concentrations ( P <0.01 for both hormones), with no difference between the trials. In conclusion, repeated short-duration sprints interspaced with 30-s recovery periods in moderate hypoxia caused further increase in blood lactate compared with the same exercise under normoxic conditions among female team-sport athletes. However, exercise-induced GH and cortisol elevations or power output during exercise were not markedly different regardless of the different levels of inspired oxygen.

E-MHK-0103 (Mineraxin™): A Novel Nutraceutical with Biological Properties in Menopausal Conditions.

Menopause-derived estrogen deprivation and related endocrine factors are linked to some symptoms typical of middle-aged women, such as hot flashes, aches, joint pain, stiffness, depressed mood, bone degeneration, nutritional dysfunction, or difficulty to maintain body mass. Clinical approaches to these problems often involve hormone replacement therapy and other modalities of therapeutic intervention. However, the well-known side effects associated with other pharmacological alternatives have led physicians and patients to pursue new strategies to alleviate these symptoms. As a physiological state, the first recommended option is a natural and healthy therapy, alone or in combination with pharmacotherapy in severe cases. Among other natural alternatives, E-MHK-0103, a nutraceutical lipoprotein extracted from Mytilus galloprovincialis, was found to have beneficial properties. We reviewed numerous high-impact references to show the controversies over the current treatments used to alleviate menopausal symptoms, and presented the results obtained with E-MHK-0103 as a good natural alternative. E-MHK-0103 showed positive effects on hot flashes, mood swings, joint pain and bone stability, associated with its glucosamine-related anti-inflammatory effect and its high content of vitamins, minerals, iron and other substances, such as selenium and vitamin E. A significant increase in serum growth hormone, mediated by the hepatic secretion of insulin growth factor-1, and a slight decrease in bone alkaline phosphatase, calcium and β-crosslaps concentrations contribute to its beneficial impact on bone turnover. E-MHK-0103 also showed a powerful antioxidant effect and an increase in iron stores, of particular importance in women with low basal ferritin levels. The findings of this review confirm the efficiency of natural therapies in menopause symptoms, and EMHK- 0103 as a healthy choice for inclusion into clinical practice.

Altered somatotroph feedback regulation improves metabolic efficiency and limits adipose deposition in male mice

Several transgenic mouse models with disruption in the growth hormone (GH) axis support the role of GH in augmenting metabolic homeostasis. Specifically, interest has focused on GH’s lipolytic properties and ability to affect adipose deposition. Furthermore, both GH and insulin growth factor 1 (IGF-1) may also play a direct or indirect role in adipose development. The somatotroph insulin-like growth factor-1 receptor knockout (SIGFRKO) mouse with only a modest increase in serum GH and IGF-1 demonstrates less adipose tissue than controls. In order to characterize the metabolic phenotype of SIGFRKO mice, histologic analysis of fat depots confirmed a smaller average diameter of adipocytes in the SIGFRKO mice compared to controls. These changes were accompanied by an increase in lipolytic gene expression in fat depots. Indirect calorimetry performed on 6–8week old male mice and again at 25weeks of age demonstrated that SIGFRKO mice, at both ages, had a higher VO2 and increased energy expenditure when compared with controls. The calculated respiratory exchange ratio (RER) was lower in the younger SIGFRKO mice compared to controls. No differences in food consumption or in either ambulatory or total activity were seen between SIGFRKO and control mice in either age group. These studies highlight the role of GH in adipose deposition and its influence on the expression of lipolytic genes resulting in an altered metabolic state, thus providing a mechanism for the decrease in weight gain seen in the SIGFRKO mouse model.

The adipokine leptin mediates muscle- and liver-derived IGF-1 in aged mice

Muscle- and liver-derived IGF-1 play important roles in muscle anabolism throughout growth and aging. Yet, prolonged food restriction is thought to increase longevity in part by lowering levels of IGF-1, which in turn reduces the risk for developing various cancers. The dietary factors that modulate IGF-1 levels are, however, poorly understood. We tested the hypothesis that the adipokine leptin, which is elevated with food intake and suppressed during fasting, is a key mediator of IGF-1 levels with aging and food restriction. First, leptin levels in peripheral tissues were measured in young mice fed ad libitum, aged mice fed ad libitum, and aged calorie-restricted (CR) mice. A group of aged CR mice were also treated with recombinant leptin for 10days. Later, aged mice fed ad libitum were treated with saline (VEH) or with a novel leptin receptor antagonist peptide (Allo-aca) and tissue-specific levels of IGF-1 were determined. On one hand, recombinant leptin induced a three-fold increase in liver-derived IGF-1 and a two-fold increase in muscle-derived IGF-1 in aged, CR mice. Leptin also significantly increased serum growth hormone levels in the aged, CR mice. On the other, the leptin receptor antagonist Allo-aca did not alter body weight or muscle mass in treated mice compared to VEH mice. Allo-aca did, however, produce a significant (20%) decline in liver-derived IGF-1 as well as an even more pronounced (>50%) decrease in muscle-derived IGF-1 compared to VEH-treated mice. The reduced IGF-1 levels in Allo-aca treated mice were not accompanied by any significant change in growth hormone levels compared to VEH mice. These findings suggest that leptin receptor antagonists may represent novel therapeutic agents for attenuating IGF-1 signaling associated with aging, and could potentially mimic some of the positive effects of calorie restriction on longevity.