Localization of the epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) in the bovine testis

In the last few decades, several growth factors were identified in the testis of various mammalian species. Growth factors are shown to promote cell proliferation, regulate tissue differentiation, and modulate organogenesis. In the present investigation we have studied the localization of EGF and EGFR in the adult bovine testis by means of immunohistochemical method. Our results demonstrated that EGF and EGFR were localized solely to the bovine testicular germ cells (spermatogonia, spermatocytes, and round spermatids). In contrast, the somatic testicular cells (i.e., Sertoli, Leydig, and myofibroblast cells) exhibited no staining affinity. EGF and EGFR were additionally detected in the epithelial lining of straight tubules and rete testis. Interestingly, the distribution of EGF and EGFR in the germ cells was mainly dependent upon the cycle of the seminiferous epithelium since their localization appeared to be preponderant during the spermatogonia proliferation and during the meiotic and spermiogenic processes. In conclusion, such findings may suggest that EGF and EGFR are important paracrine and/or autocrine regulators of spermatogenesis in bovine.     

Roles of epidermal growth factor (EGF) in the growth and differentiation of human endometrium

Endometrial tissues undergo drastic changes during menstrual cycle. After menstruation, they proliferate and differentiate into cells with secretory activity in the preparation for egg implantation. Although sex steroids play an important role in the development of endometrial tissues, sequential events occurring in the endometrium can not be fully explained by the direct actions of sex steroids. In this study, we offer evidences that EGF is released from endometrial cells and they possess the receptor for EGF. These findings prompted us to explore the biological roles of EGF in endometrial tissues. Here we clearly demonstrate that EGF is involved in the proliferation of endometrial cells. Moreover, EGF is found to enhance both glycogenesis and glycogenolysis, thus increasing the supply of glucose for blastocysts. We further set forth that EGF augments the capacity of progestin receptor and release of prostaglandins in endometrial cells. In summary, this study emphasizes that EGF may participate in the development of human endometrial tissues in concert with sex steroids, thus contributing to the acquisition of receptivity of eggs in the endometrium.     

Insulin-like growth factor-1 (IGF-1) and growth hormone (GH) in immunity and inflammation

In recent years many efforts have been undertaken to elucidate the complex interactions between mediators of the endocrine system and the immune system. The main effector of growth hormone (GH) is insulin-like growth factor-1 (IGF-1), an endocrine mediator of growth and development under physiological conditions. Besides this important function, IGF-1 also plays a prominent role in the regulation of immunity and inflammation. This article will address the involvement of IGF-1 in innate as well as acquired immunity and host-defense. We also discuss the role of IGF-1 in the course of inflammatory disorders, including sepsis and sepsis-induced catabolism as well as degenerative arthritis. Based on recent insights, we finally examine the pathophysiological background, potential pitfalls and perspectives of IGF-1 suppletion therapy in these conditions.     

Involvement of growth hormone (GH) and insulin-like growth factor (IGF) system in ovarian folliculogenesis

During the last decade, involvement of growth hormone (GH), insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in ovarian folliculogenesis has been extensively studied. This review provides an update on the GH, IGF system and their role in ovarian follicular development. In vitro studies and knockout experiments demonstrated an important role of GH in preantral follicle growth and differentiation through their binding with GH receptors, which are located both in the oocyte and follicular somatic tissues. Furthermore, GH stimulates the development of small antral follicles to gonadotrophin-dependent stages, as well as maturation of oocytes. With regard to the IGF system, IGF-I has no effects on primordial follicle development, but both IGF-I and IGF-II stimulate growth of secondary follicles. Depending on the species studies and method used, these proteins have been detected in oocytes and/or somatic cells. In antral follicles, these IGFs stimulate granulosa cell proliferation and steroidogenesis in most mammals. The bioavailability of IGFs is regulated by a family of intrafollicular expressed IGF binding proteins (IGFBPs). Facilitation of IGF can be increased through the activity of specific IGFBP proteases, which degrade the IGF/IGFBP complex, resulting in the production of IGFBP fragments and release of attached IGF.     

Cloning and characterization of the growth hormone-dependent insulin-like growth factor binding protein (IGFBP-3) in the rat.

We report for the first time the complete amino acid sequence for the growth hormone dependent insulin-like growth factor binding protein (IGFBP-3) in the rat. A human IGFBP-3 clone was generated using the polymerase chain reaction (PCR) and used to screen a rat liver cDNA library. cDNA clones of the rat IGFBP-3 were isolated and the full amino acid sequence deduced. The sequence begins with a putative, 26 amino acid signal peptide followed by a 265 amino acid binding protein. The amino acid sequence is over 80% homologous with the equivalent human IGFBP-3 form and shows complete conservation of 18 cysteine residues that are clustered at the amino and carboxy ends of the protein. IGFBP-3 is the binding subunit of the major circulating IGFBP in the rat, and hence the availability of precise structural data and cDNA probes provides an important opportunity for a detailed study of the control of IGFBP-3 synthesis at the level of gene expression.     

生长激素和生长激素受体的多样性

生长激素及其受体对动物生长发育起着重要的作用。转录过程选择性剪接和存在多种降解途径可能是GH或GHR产生多样性的原因。随着GH结构形态的改变,其功能也在发生变化。GH基因的多样性对鸡的抗病选择性反应与产蛋性能有相关,GH和GHR基因的多样性会影响奶牛的产奶生产性能。GHR的分子多样性可能导致动物生长发育模式的变异,例如动物的矮小病。     

Skeletal growth and function in the California gull (Larus californicus)

Although the bones of rapidly growing animals are composed of weak tissue, they often must function in locomotor activity. We address the conflict between development and skeletal function by analysing the ontogeny of skeletal strength in the California gull, Larus californicus. Changes in shape and mechanical properties of the femur, tibia, tarsometatarsus, humerus, ulna and carpometacarpus were analysed in a complete post-hatching growth series. During post-hatching growth, strength and stiffness of the skeletal tissue increases six- to ten-fold. At hatching, long bones of the wing are relatively weak and they remain so throughout the major portion of the growth period. However, in the hind limb, relatively thick bones in juveniles compensate for the weak tissue such that the force required to break the bones remains constant relative to body mass. This difference between hind limb and wing parallels the development of locomotor function; young gulls begin to walk within a day or two of hatching, but they do not fly until they are fully grown. Thus, in the bones of the hind limb, the conflict between rapid growth and skeletal function is solved by negative allometry of bone thickness.
After young gulls reach adult size, the breaking strength of the wing bones increases three- to four-fold, the mass of the pectoralis muscle triples and the surface area of the wing doubles. The one aspect of wing development that is not delayed until shortly before fledging is linear growth of the bones. Bones of the wing increase in length at a rapid and relatively constant rate from the time of hatching to the attainment of adult size. Relatively early initiation of linear growth of the wing bones suggests that the rate at which bones grow in length may be the rate limiting factor in wing development.     

Seasonal regulation of the growth hormone-insulin-like growth factor-I axis in the American black bear (Ursus americanus)

The American black bear maintains lean body mass for months without food during winter denning. We asked whether changes in the growth hormone/insulin-like growth factor-I (GH-IGF-I) axis may contribute to this remarkable adaptation to starvation. Serum IGF-I levels were measured by radioimmunoassay, and IGF-binding proteins (IGFBPs) were analyzed by ligand blotting. Initial studies in bears living in the wild showed that IGF-I levels are highest in summer and lowest in early winter denning. Detailed studies in captive bears showed that IGF-I levels decline in autumn when bears are hyperphagic, continue to decline in early denning, and later rise above predenning levels despite continued starvation in the den. IGFBP-2 increased and IGFBP-3 decreased in early denning, and these changes were also reversed in later denning. Treatment with GH (0.1 mg·kg(-1)·day(-1) × 6 days) during early denning increased serum levels of IGF-I and IGFBP-3 and lowered levels of IGFBP-2, indicating that denning bears remain responsive to GH. GH treatment lowered blood urea nitrogen levels, reflecting effects on protein metabolism. GH also accelerated weight loss and markedly increased serum levels of free fatty acids and β-hydroxybutyrate, resulting in a ketoacidosis (bicarbonate decreased to 15 meq/l), which was reversed when GH was withdrawn. These results demonstrate seasonal regulation of GH/IGF-I axis activity in black bears. Diminished GH activity may promote fat storage in autumn in preparation for denning and prevent excessive mobilization and premature exhaustion of fat stores in early denning, whereas restoration of GH/IGF activity in later denning may prepare the bear for normal activity outside the den.     

(Aminooxy)acetic acid inhibits petunia growth and gibberellin- and cytokinin-stimulated growth in bioassays

(Aminooxy)acetic acid (AOA) was applied to greenhouse-grown petunias and was used in bioassays for three plant growth hormones so that its growth regulator properties could be studied. In greenhouse studies foliar sprays of 4.8–12 mm AOA inhibited vegetative growth of petunia seedlings (Petunia xhybrida Vilm. White Flash). When gibberellin A ₃ (GA₃) was applied to shoot tips previously treated with AOA, plant growth was stimulated, but there was no AOA x GA₃ interaction. Some changes in petunia leaf morphology induced by AOA were reversed by GA₃. AOA inhibited elongation of corn coleoptile segments (Zea mays L. B73 x Mol7) whether or not 10 m indole-3-acetic acid (IAA) was present, but there was no AOA x IAA interaction. AOA reduced lettuce hypocotyl (Lactuca sativa L. Grand Rapids) elongation induced by GA₃ and radish cotyledon (Raphanus sativus L. Champion) expansion induced by benzyladenine (BA). We propose that AOA interferes with postsynthetic metabolism of plant hormones during cell elongation induced by GA₃ and cell expansion induced by BA.Abbreviations AOA (aminooxy)acetic acid - GA₃ gibberellin A₃ - IAA indole-3-acetic acid - BA benzyladenine     

Growth hormone and insulin-like growth factor-I measurements in high growth (hg) mice

Effects of a recessive gene causing high growth (hg) were studied on two major components of the growth axis in mice. Plasma and pituitary levels of growth hormone and plasma levels of insulin-like growth factor I (IGF-I) were measured in three lines homozygous for hg, each compared with a control line of alike genetic background but wild type for the hg locus (Hg). Line Gh (hghg) and line GH (HgHg) are from a line which had undergone long-term selection for high postweaning weight gain; line Ch (hghg) and line CH (HgHg) were extracted from the second backcross of Gh to C57BL/6J; line L54 (hghg) was from the sixth backcross to C57BL/6J (B6) (HgHg). Pituitary GH levels and plasma IGF-I levels were measured in both sexes at 3, 4.5, 6 and 9 wk of age. Plasma growth hormone was measured in 8- to 12-wk-old males at hourly intervals from 08.00 to 17.00. Body weight in lines homozygous for hg at 6 and 9 wk of age was 10-30% greater than in control lines. The ontogeny of this increased growth depended on genetic background. Pituitary growth hormone content was 52% lower in the two hghg lines measured (lines Ch and Gh) than in control lines at 4.5, 6 and 9 wk. Plasma growth hormone levels were also much lower in hg mice, with values only 20-30% of those in their respective controls. hg lines showed consistently low plasma growth hormone levels throughout the 9 hr sampling period, while control lines expressed the characteristic pulsatile hormone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) expression during induced luteolysis in the bovine corpus luteum

Angiogenic factors, like vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), and their receptors, are strongly regulated during the development of bovine corpus luteum (CL). The aim of this study was to investigate real-time changes of these factors in luteal tissue of cows (n = 4-5 per group) in the mid-luteal phase (day 8-12) after intramuscular injection of the PGF2alpha-analog Cloprostenol. Before (control) and 2, 4, 12, 48, and 64 hr after prostaglandin (PG) injection, CL were collected by transvaginal ovariectomy. RT-PCR for VEGF, VEGF-receptor type 1 (VEGF-R1), VEGF-R2, acidic FGF (FGF-1), basic FGF (FGF-2), and FGF-receptor (FGF-R) was performed. Additionally, the protein concentration for VEGF was determined. The mRNA expression of VEGF and its two receptors (VEGF-R1 and -R2) was significantly downregulated during structural luteolysis (after 12 hr). VEGF protein concentration already significantly declined 2 hr after PGF2alpha. Surprisingly FGF-1 and FGF-2 were significantly and maximally upregulated during functional luteolysis (until 12 hr). Furthermore, FGF-R mRNA was significantly upregulated at 2 hr after PGF2alpha, when compared with the control group. During structural luteolysis, the expression of FGFs and their receptors was not significantly different from control, except FGF-2 mRNA, which was downregulated at 64 hr. We conclude that the cessation of VEGF-support for the CL plays a role during structural luteolysis, whereas FGFs seem to have a major impact on functional luteolysis. The possible role of these growth factors could be a transient counter-regulation of luteolysis, but also an involvement in preventing inflammatory reactions during luteal regression.     

Variation in growth of the detritivore-shredder Sericostoma personatum (Trichoptera)

1. We investigated the growth of the detritivore-shredder Sericostoma personatum by feeding groups of larvae on a fresh macrophyte, Potamogeton perfoliatus , conditioned sitka spruce needles, Picea sitchensis , conditioned alder leaves, Alnus glutinosa , conditioned ash leaves, Fraxinus excelsior , and a fresh filamentous green alga, Microspora sp. A sixth treatment group of larvae was fasted.
2. The nitrogen content of the food items ranged from 1.4% dry weight (DW) for Picea needles to 4.4% DW for Microspora filaments. Consumption of the various food items by Sericostoma differed significantly, being highest for Picea , and lowest for Potamogeton and Microspora .
3. The instantaneous growth rate ranged from −1.3% DW day⁻¹ in the fasting group to 0.75% DW day⁻¹ in the Alnus group. The growth rate of larvae fed on Alnus , Fraxinus and Microspora was similar, and significantly higher than that of the other three groups. An increase in the size of larval cases followed the same pattern as larval growth, although with less variation between food items.
4. Larvae fed on Microspora exhibited the greatest increase in fat content, while that of the larvae fed on Picea and those in the fasting group decreased. The gross growth efficiency (G/I%) of Sericostoma (larva + case) ranged from 2% when fed on Picea to 34% when fed on Microspora . Consumption was significantly correlated with the nutrient content of food items, whereas G/I% and growth rate were only weakly related to food quality.
5. The growth of Sericostoma varies with diet and the food items sustaining highest growth rate are not necessarily the 'typical' shredder food resources.     

Geratodontology and horn growth of the impala (Aepyceros melampus)

Examination of the jaws of an impala population showed advanced wear on mandibular M1 compared with other ungulates which have been examined. This could lead to an erroneous interpretation of age if based upon mandibular tooth wear alone. Explanations are offered for this pattern in terms of the apparent pattern of wear of the impala molar teeth. Suggestions are also put forward for a method of determining specific age, from a conceptual wear model, when only extreme parameters are known. Horn growth in the male is also described.     

Influence of boron on the growth and biochemical changes in plant growth promoting rhizobacteria (PGPR) inoculated banana plantlets

The effects of rhizobacteria inoculation in modified MS medium containing boron (1 and 10 μM) on the biochemical components, physiological characteristics and mineral content of the in vitro banana plantlets were carried out. The presence of rhizobacteria in the medium supplemented with boron at two concentrations: 1 and 10 μM resulted in an improvement in growth and root biomass compared to the control (uninoculated). Rhizobacteria inoculation also produced an increase in protein, nitrate, soluble nitrogen and chlorophyll contents of the plantlets cultured in MS modified medium containing boron. An increase in percentage of growth (>295%) was shown when boron was applied into medium inoculated with Bacillus sphaericus UPMB10. The effectiveness of inoculation is increased when associated with boron, nitrogen or carbon into the medium. Thus, these bacterial strains could be used as a bioenhancer for growth of in vitro banana plantlets.