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Topic:Growth Hormone
Growth hormone (GH) in horses is a peptide hormone produced by the pituitary gland, playing a significant role in growth, metabolism, and overall development. It influences various physiological processes, including protein synthesis, cell growth, and the regulation of bone and muscle development. In equine physiology, GH impacts energy metabolism and can affect performance and recovery. Researchers study the secretion patterns, regulatory mechanisms, and effects of GH to understand its role in equine health and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, regulation, and implications of growth hormone in horses, providing insights into its effects on growth, metabolism, and athletic performance.
Identification and partial purification of serum growth hormone binding protein in domestic animal species. The chemical nature and variations in serum concentrations of growth hormone binding protein (GHBP) from humans, rabbits, and rodents have been reported. To date little is known about the GHBP of domestic animals. Therefore, we initiated these studies to determine whether a serum GHBP was present in domestic animals and to purify the binding protein (BP) from serum of selected species. Using a dextran-coated charcoal separation assay, specific growth hormone (GH) binding was demonstrated in ovine, bovine, chicken, human, goose, porcine, and equine serum (listed in sequence from lowest to highe...
Cloning the cDNA for horse growth hormone and expression in Escherichia coli. A 514 bp cDNA transcript coding for 78% of horse (Equus caballus.) GH has been cloned and sequenced. The deduced amino acid sequence corresponded precisely to that previously obtained by protein sequencing and, in addition, provided new sequence information for the signal peptide. The missing 3' fragment of the cDNA was reconstructed using synthetic oligonucleotides and site-specific directed mutagenesis. The complete cDNA sequence was then inserted into an expression vector (PIN-III-lppp-5) which utilizes a bacterial signal peptide to secrete the expressed product into the periplasmic space o...
Partial purification and characterization of rhinoceros gonadotropins, growth hormone, and prolactin: comparison with the horse and sheep. The rhinoceros is an endangered species related to the horse family. Little is known of its reproductive endocrinology. The objectives of this study were to partially purify rhinoceros pituitary hormones, determine which assays could be used for their assessment, and to ascertain whether rhinoceros LH possesses the intrinsic FSH activity of equine LH. A single pituitary each from a White (1.3 g) and a Black (1.2 g) Rhinoceros was homogenized and extracted (pH 9.5), then subjected to pH and salt fractionation, and ion-exchange chromatography (DEAE and Sephadex SP-C50) to yield partially purifie...
Equine growth hormone. Detection of immunoreactive sequences using poly- and monoclonal antibodies. The immunochemical behavior of several fragments of equine growth hormone (eGH) was examined using competitive binding assays with antibodies (Abs) to eGH obtained from different sources. Antigenicity was detected within the sequences 5-72 and 73-123 by rabbit Abs to eGH and by three mouse monoclonal antibodies (MAbs) produced by using bovine growth hormone as immunogen, but showing heteroclitic properties towards eGH. The polyclonal Abs to eGH also recognized as immunoreactive two smaller peptides corresponding to the amino acid residues 52-72 and 110-123. By contrast, the heteroclitic Abs to...
Conformational comparison in the growth hormone family. 1. The method of Kubota et al. [Biochim. biophys. Acta 701, 242-252 (1982)] was applied to several members of the growth hormone family in order to examine their conformational homology. 2. The method neither detects differences between rat, cow, sheep, horse and alpaca hormones, nor between monkey and human hormones. 3. Lack of homology between primate and non-primate growth hormones was found in segments 42-49 and 184-191. The first fragment could be linked to species-specificity.
Primary structure of equine pituitary prolactin. Equine prolactin was determined to be a single chain protein of 199 amino acid containing two tryptophan and six cysteine residues, as found in other mammalian prolactins. The primary sequence of equine prolactin was obtained by automated Edman analyses of S-carboxymethylated protein and proteolytic fragments of modified protein. Of the known prolactin sequences, equine prolactin shows closest homology with porcine (93%) and fin whale (87-91%) prolactins. Genetic mutations have produced changes in 17 of 199 residues of equine prolactin relative to its putative ancestral precursor. Since equine...
Ethoxyformylation of histidine residues in equine growth hormone. Reactivity of histidine residues in equine growth hormone to ethoxyformic anhydride was studied. The existence of two kinetically different sets was demonstrated: one of them including only the slow reacting histidine 169 (k = 0.164 min-1) and the other containing fast reacting histidines 19 and 21 (k = 0.892 min-1). A correlation between the decrease in the capacity to compete with 125I-labeled hormone for rat liver binding sites and the degree of ethoxyformylation of the fast group was found. Circular dichroism studies indicated no significant conformational changes in the protein with all t...
Growth and calcium metabolism in horses fed varying levels of protein. The effect of level of protein intake on growth and calcium metabolism was studied in 24 foals. Starting at four months old, the foals were fed one of three diets containing all nutrients, with the exception of protein, at levels recommended by the United States National Research Council Subcommittee on Horse Nutrition for a 12 month period. The protein levels in the three diets were 9 per cent (low protein) 14 per cent (NRC recommended level) and 20 per cent (high protein). The foals fed the low protein diet were changed to the high protein diet after 140 days when they were nine months old. ...
Application of recombinant DNA techniques to structure-function studies of equine protein hormones. Complementary (c)DNA libraries have been made from horse pituitary gland and endometrial cup tissues with the aim of isolating the genes for the horse gonadotrophins (FSH, LH and CG) and growth hormone (GH). Southern (DNA) and Northern (RNA) blotting techniques were used to demonstrate that several heterologous (human and ovine) cDNA probes would be adequate for isolating the horse genes. A human cDNA probe was then used to isolate the horse gonadotrophin alpha-subunit cDNA from the pituitary and endometrial cup libraries. The nucleotide sequences from both tissue sources were identical, there...
Application of the peroxidase-antiperoxidase procedure to the localization of pituitary hormones and calcitonin in various domestic animals and human beings. Specific cell populations in the pituitary glands of the rat, cat, pig, and human being were positive for thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH). When reacted with prediluted rabbit anti-human TSH, LH, and FSH, antisera were not positive for the demonstration of these hormones in the horse, cow, or dog. Immunocytochemical staining was obtained in the horse, cow, and dog by the use of a primary antiserum against a specific beta-subunit of bovine TSH. The immunocytochemical staining of TSH, LH, FSH, adrenocorticotropic hormone, growth ...
Hormonal responses to high and low planes of nutrition in weanling thoroughbreds. Growth-related skeletal diseases in young horses have been associated with high planes of nutrition, although the mechanisms underlying such an association have not been determined. It is likely that nutrition-induced effects on growth rate or growth quality involve the endocrine system. Hormonal and metabolic responses to the ingestion of meals containing either 80% (diet A) or 160% (diet B) of National Research Council energy and protein recommendations were examined in eight Thoroughbred weanling horses after 3 wk of dietary adaptation. After 24 h fasts, prefeeding serum concentrations of t...
Hormonal changes in the immature rat after administration of pregnant mare serum gonadotrophin: influence of body weight. We have shown previously that pregnant mare serum gonadotrophin (PMSG) induces ovulation only in rats weighing over 60 g on the day of injection. The under-60 g rats do not ovulate although they secrete a preovulatory surge of a pleiomorphic form of LH. Presumably this pleiomorph is inactive. Comparisons were made of plasma hormone concentrations in rats treated with PMSG that weighed over and under 60 g. The measurements were made on samples taken between 13.00 and 22.00 h on the day of the expected preovulatory LH surge. Prolactin and corticosterone levels were lower in the lighter group com...
Human, bovine, and equine growth hormone antibodies in patients treated with human growth hormone. The immunological behavior of sera from hypopituitary patients treated with human GH (hGH) has been studied by homologous and heterologous RIAs using 125I-labeled hormones. Along with antibodies against hGH, antibodies exhibiting antibovine and antiequine GH (anti-bGH and anti-eGH, respectively) activities were also found. Displacement experiments showed that hGH was an effective competitor of 125 I-labeled hGH, whereas bGH and eGH were quite inefficient. Conversely, when the tracer was 125I-labeled bGH, both bGH and eGH were good displacers, while the human hormone was poor. The values of the...
Immunological properties of two related fragments from human and equine growth hormones. The immunological properties of a synthetic human growth hormone fragment comprising the amino acids 73 through 128 and of the homologous natural horse growth fragment formed by amino acids 73 through 123, have been comparatively studied. Antisera obtained in rabbits inoculated with the native human hormone or with the fragments, were used. By hemagglutination experiments both fragments have the same reactivity toward the anti-human growth hormone serum, but complement fixation curves detect the existence of at least two populations of antibodies presumably originated against the sequence 73-1...
Reaction of bovine and equine growth hormones with tetranitromethane. Bovine and equine growth hormones were chemically modified with tetranitromethane, at pH 7.4 during 5 h and at pH 8.0 in the presence of 8 M urea during 1 h. a) Both hormones have very similar but not identical reactivities. b) The nitration of the reactive tyrosines and tryptophan residues at pH 7.4 produces no detectable changes in their immunological or somatotrophic activities. C) The nitration of all tyrosine residues in both hormones gives rise to a complete loss of somatographic activity with no alteration of the immunological activity.
Effects of environmental and other stressors on blood hormone patterns in lactating animals. Recent data on various environmental stressors and blood hormone patterns are presented for lactating cattle. Known stressor effects of such factors as environmental temperature, air pollution, and noise on the plasma thyroxine, growth hormone, cortisol, prolactin, progesterone, luteinzing hormone, epinephrine, and norepinephrine of lactating cattle are discussed. Information on stressor effects is lacking on glucagon, insulin, vasopressin, calcitonin, oxytocin, thyrotrophic hormone, follicle stimulating hormone, melatonin, parathyroid hormone, and estrogens in the lactating cow. The importanc...
Detection of immunologically active zones in equine growth hormone. Peptide fragments, obtained from equine growth hormone by cyanogen bromide cleavage and further chemical treatment, were isolated and identified. Their immunological reactivities were tested by hemagglutination and complement fixation methods using rabbit antisera against native hormone. Antigenic determinants were detected in the fragments comprising amino acid sequences 5-72 and 73-123, this last one being predominant. Fragment 124-178 had very low reactivity. Nitration of peptide 73-123 did not modify its immunological properties,but oxidation diminished them. Comparison of the antigenicity...
Amino acid sequences around the cystine residues in horse growth hormone. The cystine-containing peptides of horse growth hormone were isolated and their amino acid sequences determined. Four unique half-cystine residues occur in two peptides, one containing 11 and the other, at the C-terminus of the protein, 15 amino acids. These sequences are compared with published data on growth hormones from other species.
Preparation and properties of growth hormone from equine pituitary glands. Equine growth hormone has been prepared from acetone-dried residues following extraction of gonadotropins from fresh frozen equine pituitary glands. The growth hormone appeared as a single fraction by gel filtration on Sephadex G-50 and ultracentrifugation. A sedimentation constant of 3.12 was obtained. Preliminary end-group analysis suggested phenylalanine at both aminoand carboxy-terminals. Amino acid analysis of the growth hormone was performed. Four components of equine growth hormone were separated by polyacrylamide column electrophoresis and all 4 were shown to contain growth hormone act...
