Sequence of a cDNA encoding dog insulin-like growth factor I

CRISPR/Cas9-Mediated Specific Integration of Fat-1 and IGF-1 at the pRosa26 Locus

Many researchers have focused on knock-in pigs for site-specific integration, but little attention has been given to genetically modified pigs with the targeted integration of multiple recombinant genes. To establish a multigene targeted knock-in editing system, we used the internal ribosome entry site (IRES) and self-cleaving 2A peptide technology to construct a plasmid coexpressing the fatty acid desaturase (Fat-1) and porcine insulin-like growth factor-1 (IGF-1) genes at equal levels. In this study, pigs were genetically modified with multiple genes that were precisely inserted into the pRosa26 locus by using the clustered regularly spaced short palindrome repeat sequence (CRISPR)/CRISPR-related 9 (Cas9) system and somatic cell nuclear transfer technology (SCNT) in combination. Single copies of the Fat-1 and IGF-1 genes were expressed satisfactorily in various tissues of F0-generation pigs. Importantly, gas chromatography analysis revealed a significantly increased n-3 polyunsaturated fatty acid (PUFA) level in these genetically modified pigs, which led to a significant decrease of the n-6 PUFA/n-3 PUFA ratio from 6.982 to 3.122 (*** p < 0.001). In conclusion, the establishment of an editing system for targeted double-gene knock-in in this study provides a reference for the precise integration of multiple foreign genes and lays a foundation for the development of new transgenic pig breeds with multiple excellent phenotypes.

Evaluation of serum insulin-like growth factor-1 and 26S proteasome concentrations in healthy dogs and dogs with chronic diseases depending on body condition score

In patients suffering from chronic diseases, the objective assessment of metabolic states could be of interest for disease prognosis and therapeutic options. Therefore, the aim of this study was to assess insulin-like growth factor-1 (IGF-1) and 26S proteasome (26SP) in healthy dogs and dogs suffering from chronic diseases depending on their body condition score (BCS) and to examine their potential for objective assessment of anabolic and catabolic states. Serum concentrations of IGF-1, an anabolic hormone, and 26SP, a multiprotein complex which is part of the ubiquitin-proteasome pathway, by which the majority of endogenous proteins including the muscle proteins are degraded, were measured in 21 healthy dogs and 20 dogs with chronic diseases by canine ELISA. The concentrations of IGF-1, 26SP and their ratio (IGF-1/26SP) were set in relationship to the BCS of the dogs. When examining healthy and chronically diseased dogs separately, a positive correlation between IGF-1 and the BCS was observed in the healthy group and a negative correlation between 26SP and the BCS was noted in dogs with chronic diseases. Further, dogs suffering from chronic diseases showed higher 26SP concentrations and lower values for IGF-1/26SP than the healthy dogs. Overall, we detected a negative correlation between 26SP and the BCS and a positive correlation between IGF-1/26SP and the BCS. The results of our study indicate usability of IGF-1 for description of anabolic states, while 26SP could be useful for detection and description of catabolic states. Finally, the ratio IGF-1/26SP seems to be promising for assessment of metabolic states.

Muscular dystrophy-related quantitative and chemical changes in adenohypophysis GH-cells in golden retrievers

Duchenne muscular dystrophy (DMD) is a recessive X-linked lethal condition which affects a boy in every 3300 births. It is caused by the absence of dystrophin, a protein occurring especially within the musculoskeletal system and in neurons in specific regions of the central nervous system (CNS). Growth hormone (GH) inhibition is believed to decrease the severity of DMD and could perhaps be used in its treatment. However, the underlying pathological mechanism is not known. The golden retriever muscular dystrophy dog (GRMD) represents an animal model in the study of DMD. In this paper we investigated the morphological aspects of the adenohypophysis as well as the total number and size of GH-granulated cells using design-based stereological methods in a limited number of dystrophic and healthy golden retrievers. GH-cells were larger (32.4%) in dystrophic dogs than in healthy animals (p=0.01) and they occupied a larger portion (62.5%) of the adenohypophysis volume (p=0.01) without changes in either adenohypophysis volume (p=0.893) or total number of GH-granulated cells (p=0.869). With regard to ultrastructure, granulated cells possessed double-layer electron-dense granules which were evenly distributed in the cytosol. Furthermore, these granules in dystrophic animals occupied a larger proportion of GH-granulated cell volume (66.9%; p=0.008) as well as of all GH-cells in the whole pars distalis of adenohypophysis (77.3%; p=0.035), albeit IGF-1 serum concentration was lower in severe cases. This suggests difficulties in the GH secretion that might possibly be associated to dystrophin absence. In contrast to earlier reports, our data suggest that a lower IGF-1 concentration may be more related to a severe, as opposed to a benign, clinical form of muscular dystrophy.

Testosterone inhibition of growth hormone release stimulated by a growth hormone secretagogue: studies in the rat and dog

Anabolic steroids are frequently taken by athletes and bodybuilders together with recombinant human GH (rhGH), though there is some scientific evidence that the use of anabolic steroids reverses the rhGH-induced effects. Recently, we have shown that treatment with rhGH (0.2 IU/kg s.c., daily x 12 days) in the dog markedly reduced the canine GH (cGH) responses stimulated by EP51216, a GH secretagogue (GHS), evaluated after 3 and 5 daily rhGH injections, and that the inhibition was still present a few days after rhGH discontinuation. The aim of the present study was to evaluate in the dog the GH response to EP51216 (125 mug/kg i.v.) in a condition of enhanced androgenic function (i.e. acute injection or 15-day treatment with testosterone at the dose of 2 mg/kg i.m. on alternate days), and in the hypophysectomized rat the hypothalamic and hippocampal expression of ghrelin, the receptor of GHSs (GHS-R), GH-releasing hormone (GHRH) and somatostatin (SS) after specific hormonal replacement therapies (testosterone, 1 mg/kg/day s.c.; hydrocortisone, 500 mug/kg/day s.c.; rhGH, 400 mug/kg/day s.c.; 0.9% saline 0.1 ml/kg/day s.c.; x11 days). In the dog experiments, under baseline conditions, a single injection of EP51216 elicited an abrupt rise of plasma cGH. Twenty-four hours from the acute bolus injection of testosterone, C(max) and AUC(0-90) of the GHS-stimulated cGH response were significantly lower than baseline cGH response; 5 days later, there was still a significant decrease of either parameter versus the original values. Short-term treatment with testosterone markedly reduced the GHS-stimulated cGH responses evaluated during (5th bolus) and at the end (8th bolus) of testosterone treatment. Four and 8 days after testosterone withdrawal, the EP51216-stimulated cGH response was still significantly reduced when compared with that under baseline conditions. Plasma concentrations of insulin-like growth factor 1 (IGF-1) were stable until the 5th bolus of testosterone and decreased progressively in the remaining time of the testosterone treatment; 4 and 8 days from treatment withdrawal, IGF-1 levels were still suppressed. In rat studies, hypothalamic mRNA levels of GHS-R were significantly reduced by treatments with testosterone and hydrocortisone, whereas hippocampal expressions of ghrelin, GHRH and SS were reduced by rhGH replacement therapy. In conclusion, these studies show that a single administration of testosterone can abrogate the cGH response ensuing acute stimulation by a GHS; the inhibitory effect of testosterone on the cGH response to GHS is present during and even 8 days after termination of a short-lived treatment with testosterone; these events occur via a

Reconciling data from transgenic mice that overexpress IGF-I specifically in skeletal muscle

Transgenic mice that overexpress insulin-like growth factor-1 (IGF-I) specifically in skeletal muscle have generated much information about the role of this factor for muscle growth and remodelling and provide insight for therapeutic applications of IGF-I for different pathological states and ageing. However, difficulties arise when attempting to critically compare the significance of data obtained in vivo by using different genetically engineered mouse lines and various experimental models. Complications arise due to complexity of the IGF-I system, since multiple transcripts of the IGF-I gene encode different isoforms generated by alternate promoter usage, differential splicing and post-translational modification, and how IGF-I gene expression relates to its diverse autocrine, paracrine and endocrine modes of action in vivo has still to be elucidated. In addition, there are problems related to specification of the exact IGF-I isoform used, expression patterns of the promoters, and availability of the transgene product under different experimental conditions. This review discusses the factors that must be considered when reconciling data from cumulative studies on IGF-I in striated muscle growth and differentiation using genetically modified mice. Critical evaluation of the literature focuses specifically on: (1) the importance of detailed information about the IGF-I isoforms and their mode of action (local, systemic or both); (2) expression pattern and strength of the promoters used to drive transgenic IGF-I in skeletal muscle cells (mono and multi-nucleated); (3) local compared with systemic action of the transgene product and possible indirect effects of transgenic IGF-I due to upregulation of other genes within skeletal muscle; (4) re-interpretation of these results in light of the most recent approaches to the dissection of IGF-I function. Full understanding of these complex in vivo issues is essential, not only for skeletal muscle but for many other tissues, in order to effectively extend observations derived from transgenic studies into potential clinical situations.

Response of dogs to short-term infusions of carbohydrate- or lipid-based parenteral nutrition

Parenteral nutrition (PN) is used to support intensive care patients. The risk for adverse metabolic effects depends on the composition of infused solutions and the duration of application. The present study in dogs compares metabolic and endocrine effects of two infusion solutions, with either triglycerides or glucose being the major energy sources, administered in a comparatively short infusion period (10 h/day). PN was administered for 9 days to two groups of five adult dogs to meet energy maintenance requirements. In group PN-LIP 61% of the total energy was derived from lipids and 22% from carbohydrates, compared with 21 and 62% in group PN-GLUC. Among routine haematology and clinical chemistry the plasma levels of glucose, triglycerides, insulin, insulin-like growth factor-I (IGF-I), glucagon, 3,5,3'-triiodothyronine and thyroxin were measured in non-infused dogs and at 2, 4, 6, and 8 h after the start of infusion at days 2 and 8 of the study. Infusions protocols did not cause gross metabolic aberrations. During the actual infusions glucose, triglyceride and insulin concentrations were elevated, each depending on the infusion solution. Concentrations of IGF-I, glucagon, 3,5,3'-triiodothyronine, thyroxin and cortisol did not change significantly. In conclusion short infusion periods of 10 h per day were tolerated by healthy dogs without adverse signs, which could improve practicability of PN also in clinical cases.

Cloning of a full-length insulin-like growth factor-I complementary DNA in the goldfish liver and ovary and development of a quantitative PCR method for its measurement

Five forms of insulin-like growth factor-I (IGF-I) complementary DNA (cDNA) were isolated by PCR from goldfish liver and ovary, using primers based on common carp IGF-I sequence. In the goldfish liver, we cloned and sequenced three IGF-I forms (1,2, and 3), and elucidated the full-length cDNA sequence using the 5'-and 3'-RACE. Two IGF-I forms (1 and 2) were cloned from the goldfish ovary and were found to have differences with respect to both size and nucleotide sequence compared to liver IGF-I. The entire liver IGF-I form 1 sequence was found to be 833 nucleotides long, containing a 483-nucleotide open reading from encoding 161 amino acids. The deduced amino acid sequence of the mature peptide was compared to IGF-I sequences of other vertebrates, and found to have 97 and 93% similarity to carp and salmon IGF-I, respectively, In this study we also developed a competitive quantitative PCR method and demonstrated an increase in IGF-I expression following treatments with growth hormone or gonadotropin-releasing hormone in the goldfish liver.

Insulin-like growth factors in poultry

A large amount of research, primarily in mammals, has defined to a great extent the pleiotropic effects of the IGF system on growth, development, and intermediary metabolism. Similar elucidations in poultry were hindered to some extent by the absence of native peptides (IGF-I and IGF-II) until their purification, followed by the production of recombinant chicken IGFs. In many ways IGF physiology in birds is similar to that in other species, including but not limited to the fact that IGF-I synthesis is both GH- and GH-independent, and that autocrine-paracrine IGF action is evident. However, it is clear that several unique differences in IGF physiology exist between birds and mammals. For example, more IGF is present in the free form in chickens, and the biological responses to the IGFs is different in several metabolic pathways in birds compared to mammals. To date, no unique IGF-II receptor has been identified in birds. Despite an increasing understanding of the IGFs in aves, several important questions remain to be answered. What is the role of IGF-II in embryo development and posthatch growth? Does an IGF-II receptor entity exist in nonmammalian species? How does nutrition affect IGF-I and IGF-II gene expression, and can this information be used to enhance poultry production? What is the biochemical composition of the IGFBPs, and what are their roles in birds? Can the genetic variation present in poultry be used to positively modify IGF gene expression and physiology? How do the IGFs regulate intermediary metabolism? What is the role of the IGFs in the etiology of several disease states associated with rapid growth in poultry, including tibial dyschondroplasia, obesity, ascites, and spiking mortality syndrome? Answers to these questions are relevant to our understanding of the basic mechanisms of IGF physiology as well as possibly assisting in the amelioration of problems found in modern poultry production.

A comparison of the effects of insulin-like growth factor-I, insulin and combined infusions of insulin and insulin-like growth factor-I on glucose metabolism in dogs

The effect of infusions of recombinant insulin-like growth factor-I (IGF-I) (34, 103 or 688 pmol kg-1 min-1), insulin (3.4, 10.3 or 68.8 pmol kg-1 min-1) or combined infusions (34 pmol IGF-I + 3.4 pmol kg-1 min-1 insulin or 103 pmol IGF-I + 3.4 pmol kg-1 min-1 insulin) on glucose metabolism was investigated in dogs using a [3-3H]-glucose infusion and euglycaemic clamp. All insulin doses decreased glucose production rate (Ra) in a dose-dependent manner (P < 0.05). All IGF-I doses decreased glucose Ra (P < 0.05) but this decrease was not dose dependent. The decrease in glucose Ra with the combined infusion of 34 pmol kg-1 min-1 IGF-I + 3.4 pmol kg-1 min-1 insulin was greater than 34 pmol kg-1 min-1 IGF-I (P < 0.05) but not different from 3-4 pmol kg-1 min-1 insulin. All insulin and IGF-I doses increased glucose utilization rate (Rd) in a dose-dependent manner (P < 0.01). The increase in glucose utilization was greater following both combined infusions than with either component infused alone (P < 0.05). Although at the doses selected, insulin and IGF-I had similar effects on glucose utilization with additive effects when the two peptides were combined, IGF-I was less effective than insulin in suppressing glucose production.