• 대한생식의학회:학술대회논문집
• /
• 1996.11a
• /
• pp.11-12
• /
• 1996

• Development and Reproduction
• /
• v.6 no.1
• /
• pp.31-35
• /
• 2002

The major urinary proteins(MUPs) of mice that bind hydrophobic molecules known as pheromones are regulated in part by the actions of growth hormone. The expression of the MUPs was therefore investigated in transgenic mice that express a human growth hormone-releasing factor gene from a metallothionein gene promoter(MT-GRF) and as a result have elevated growth hormone levels. MUPs were severely down-regulated in the urine of these animals compared to normal mice or to control transgenic mice expressing another gene(the inhibin a subunit) from the same metallothionein promoter(MT-Inh) and more MUPs disappeared in male mice than female ones. MUPs were also down-regulated in the urine of the UT-GRF-injected mice. In addition, it was observed that the urine of the MT-GRF mice included a high molecular weight protein that co-migrates with the major serum protein albumin, indicating an impairment in glomerular filtration within the kidney. The urinary loss of serum proteins was more severe in male MT-GRF mice than female ones. Thus the overexpression of human GRF mimics changes observed in MUP protein expression and glomerular function in other models of growth hormone hypersecretion with sex-dependent differential effects.

• Korean Journal of Veterinary Research
• /
• v.35 no.4
• /
• pp.671-681
• /
• 1995

This study was attempted to investigate the topographical distribution, shape and immunoreactivity of growth hormone-releasing factor(GRF)- and somatostatin(SOM)-immunoreactive neurons in the hypothalamus of the Korean squirrels(Sciurus vulgalis coreae). For the light microscopical examination of immunohistochemistry, the brains were fixed with 4% paraformaldehyde solution by means of intracardiac perfusion. And the frozen sections($40{\mu}m$ thick) were stained immunohistochemically by ABC method. Distribution of GRF immunoreactive neurons($12-17{\mu}m$) was highest in the paraventricular nucleus, moderate in the periventricular and supraoptic nuclei, and low in the arcuate nucleus and lateral hypothalamic area. Their immunoreactive fibers were found very high in the median eminence, moderately in the supraoptic, paraventricular and periventricular nuclei, and low in the arcuate nucleus and lateral hypothalamic area. SOM immunoreactive perikarya($14-18{\mu}m$) were found moderately in the periventricular nucleus near the subependymal layer of the third ventricle, and low in the arcuate and suprachiasmatic nuclei. SOM immunoreactive fibers were found high in the median eminence, and moderately or low in the arcuate and periventricular nuclei.

• Asian-Australasian Journal of Animal Sciences
• /
• v.2 no.3
• /
• pp.254-256
• /
• 1989

• BMB Reports
• /
• v.48 no.9
• /
• pp.501-506
• /
• 2015

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506]

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.2
• /
• pp.236-243
• /
• 2000

A number of developments have occurred over recent years that are being used commercially or have the potential to increase the milk yield and consequently the efficiency of dairy cows. Bovine growth hormone is the most widely known of several attempts that have been made to alter the metabolic endocrinology of dairy cows to increase the rate of milk secretion. The factors affecting the milk yield response to growth hormone, growth hormone-releasing factor, thyroxine and placental lactogen as well as to the immuno-neutralization of somatostatin are briefly considered. Secondly, the recent greater understanding of the mechanism by which the milk yield is increased following more frequent milking, which has resulted from the identification and characterization of the feedback inhibitor of lactation (FIL) protein, is reviewed. The identification of this protein provides new avenues of research which may lead to a reduction in the rate of decline in milk yield with advancing lactation or to undiminished milk yields despite a reduction in frequency with which the animals are milked.

• Clinical and Experimental Reproductive Medicine
• /
• v.23 no.3
• /
• pp.269-275
• /
• 1996

Biosynthesis and secretion of anterior pituitary hormones are under the control of specific hypothalamic stimulatory and inhibitory factors. Among them, Growth Hormone Releasing Hormone (GHRH) is the major stimulator of pituitary somatotrophs activating GH gene expression and secretion. Human GHRH is a polypeptide of 44 amino acids initially isolated from pancreatic tumors, and the gene for the hypothalamic form of GHRH is organized into 5 exons spanning over 10 kilobases (kb) on genomic DNA and encodes a messenger RNA of 700-750 nucleotides. Several neuropeptides classically associated with the hypothalamus have been found in the extrahypothalamic regions, suggesting the existence of novel sources, targets and functions. GHRH-like immunoreactivity has been found in several peripheral sites, including placenta, testis, and ovary, indicating that GHRH may also have regulatory roles in peripheral reproductive organs. Furthermore, higher molecular weight forms of the GHRH transcripts were identified from these organs (1.75 kb in testis; 1.75 and >3 kb in ovary). These tissue-specific expression of GHRH gene suggest the existence of unique regulatory mechanism of GHRH expression and function in these organs. In fact, placenta-specific and testis-specific promoters for GHRH transcripts which are located in about 10 kb upstream region of hypothalamic promoter were reported. The use of unique promoters in extrahypothalamic sites could be refered in a different control of GHRH gene and different functions of the translated products in these tissues. Somatotrophs and lactotrophs have been thought to be derived from a common bipotential progenitor, the somatolactotrophs, which give origins to either phenotypes. Although the precise mechanism responsible for the lactotroph differentiation in the anterior pituitary gland has not been yet clalified, there are several candidators for the generation of lactotrophs. In human, the presence of GHRH peptides with different size from authentic hypothalamic form in the normal anterior pituitary and several types of adenoma were demonstrated. Recently our group found the existence of immunoreactive GHRH and its transcript from the normal rat anterior pituitary (gonadotroph> somatotroph> lactotroph), and the GHRH treatment evoked the increased proliferation rate of anterior pituitary cells in vitro. The transgenic mouse models clearly shown that GHRH or NGF overexpression by anterior pituitary cells induced development of pituitary hyperplasia and adenomas particularly GH-oma and prolactinoma. Taken together, we hypothesize that the pituitary GHRH could serve not only as a modulator of hormone secretion but as a paracrine or autocrine regulator of anterior pituitary cell proliferation and differentiation. Interestingly enough, the expression of Pit-1 homeobox gene (the POU class transcription factor) was confined to somatotrophs, lactotrophs and somatolactotrophs in which GHRH receptors are expressed commonly. Concerning the mechanism of somatolactotroph and lactotroph differentiation in the anterior pituitary, we have focused following two possibilities; (1) changes in the relative levels or interactions of both hypothalamic and intrapituitary factors such as dopamine, VIP, somatostatin, NGF and GHRH; (2) alterations of GHRH-GHRH receptor signaling and Pit-1 activity may be the cause of lactotroph differentiation or pituitary hyperplasia and adenoma formation. Extensive further studies will be necessary to solve these complicated questions.

• Clinical and Experimental Pediatrics
• /
• v.50 no.7
• /
• pp.678-685
• /
• 2007

Purpose : Recent reports pointed out that gonadotropin releasing hormone analogue (GnRHa) therapy alone is not so promising for improving adult height in precocious puberty. So, that we studied the growth promoting effect of combined therapy with GnRHa and growth hormone (GH) in early pubertal girls. Methods : Twenty three early pubertal girls ($9.73{\pm}1.59yr$) with predicted adult heights (PAH) below-2 standard deviation score (SDS) were included. They were divided into two groups as follows; Group I before menarche (n=19) and Group II after menarche (n=4). After combined therapy, various growth parameters were compared between two groups and between the before and after therapy. Results : Between the two groups before therapy, chronologic age (CA), growth velocity (GV), body mass index (BMI), target height (TH), PAH and serum insulin-like growth factor binding protein-3 were not different, but BA, height and difference between bone age (BA) and CA were significantly higher and insulin-like growth factor-1 (IGF-1) was marginally higher in group II. After therapy, BA still remained higher in group II, but other parameters were not different. In both groups, after therapy, the difference between BA and CA, the ratio of BA over CA, and GV were significantly decreased, but PAH, height SDS and BMI were significantly increased. Regarding IGF-1 level, a significant increase was noted in group I, but not in group II. Conclusion : With combined therapy of GnRHa and GH, PAH in early pubertal girls might be improved significantly and even approach TH. Among them, those who were before menarche might have greater potential for the height gain than those after menarche in view of IGF-1 changes during therapy.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.12
• /
• pp.1668-1676
• /
• 2010

The somatotropic axis plays a key role in proliferation and differentiation of avian organs during both pre- and posthatching periods. This review discusses the complexity of regulation of the endocrine system for chicken development and growth by growth hormone (GH), insulin-like growth factor (IGF), and IGF binding protein (IGFBP). In addition, the thyrotropic axis, including thyrotropin-releasing hormone (TRH) and thyroid hormones ($T_4$ and $T_3$), is also involved in the GH-secreting pattern. In mammals, IGFI and -II are always sequestered in a 150 kDa non-covalent ternary complex. This complex consists of one molecule each of IGF-I or IGF-II, IGFBP-3 or IGFBP-5 and an acid labile subunit (ALS). Chick ALS is identified in different strains for the first time, and further investigation of the expression of ALS on developmental stage and ALS effect on IGF bioavailability may be addressed in the future.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.8
• /
• pp.1193-1198
• /
• 2003

An increase in frequency of administration of exogenous growth hormone (GH) or GH-releasing hormone was reported to be a model to increase blood circulating insulin-like growth factor-1 (IGF-1) and to improve growth performance in animals. We have investigated the effect of twice daily administration of GH-releasing peptide-2 (GHRP-2) on growth performance, GH responsiveness and plasma insulin-like growth factor IGF-1 in swine. We administered to eight swine, 3 control and 5 treatment, a twice daily s.c. injections of GHRP-2 ($30{\mu}g/kg\;BW$) for a period of 10 days. Every day blood samples immediately taken before injections of GHRP-2 or saline, at 08:00 h and 16:00 h, were measured for IGF-1 concentrations. Blood samples for GH assay were collected every 20 min on days 1, 6 and 10, from 1 hour before and 3 h after GHRP-2 or saline injections at 08:00 h. GH peak concentrations and GH area under curve (GH AUC) on day 1, 6 and 10 in treatment group of swine were higher than those in control swine (p<0.05). Twice daily administration of GHRP-2 caused a significantly attenuation (p<0.05) of GH peak concentrations ($80.25{\pm}13.87$, $39.73{\pm}5.72$ and $27.57{\pm}6.06ng/ml$ for day 1, 6 and 10, respectively) and GH AUCs ($3,536.15{\pm}738.35$, $1,310.31{\pm}203.55$ and $934.37{\pm}208.99ng/ml$ for day 1, 6 and 10, respectively). However, there was no significant difference in GH peak concentration and GH AUC between day 6 and 10. Plasma IGF-1 concentration levels were higher in treatment than control group of swine (p<0.05) after 3 days of the treatment, and the levels reached a plateau from day 3 to 10 of experiment. Growth performance did not alter by GHRP-2 administration, even though a numerical increase of body weight gain and feed efficiency was observed. These results indicate that twice daily administration of GHRP-2 for 10 days in swine did not significantly influence on growth performance, caused an overall attenuation of GH response, and that elevation of plasma GH concentrations caused by GHRP-2 administration increased plasma IGF-1 concentrations, even though an attenuation of GH response was observed.