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1.
Gabriel E. Bertolesi Sherene T. Vazhappilly Carrie L. Hehr Sarah McFarlane 《Pigment cell & melanoma research》2016,29(2):186-198
Light‐regulated skin colour change is an important physiological process in invertebrates and lower vertebrates, and includes daily circadian variation and camouflage (i.e. background adaptation). The photoactivation of melanopsin‐expressing retinal ganglion cells (mRGCs) in the eye initiates an uncharacterized neuroendocrine circuit that regulates melanin dispersion/aggregation through the secretion of alpha‐melanocyte‐stimulating hormone (α‐MSH). We developed experimental models of normal or enucleated Xenopus embryos, as well as in situ cultures of skin of isolated dorsal head and tails, to analyse pharmacological induction of skin pigmentation and α‐MSH synthesis. Both processes are triggered by a melanopsin inhibitor, AA92593, as well as chloride channel modulators. The AA9253 effect is eye‐dependent, while functional data in vivo point to GABAA receptors expressed on pituitary melanotrope cells as the chloride channel blocker target. Based on the pharmacological data, we suggest a neuroendocrine circuit linking mRGCs with α‐MSH secretion, which is used normally during background adaptation. 相似文献
2.
Two series of experiments were performed to identify the inhibitory center of the melanotropes in the intermediate lobe of hypophysis of the toad, Bufo japonicus. First, developmental changes in the distribution of dopaminergic neurons were examined from hatching stage to postmetamorphosis using an antiserum against dopamine synthase (tyrosine hydroxylase, TH). In the postmetamorphic toads, TH-positive cell bodies were localized in three clusters. One was the preoptic recess organ (PRO) in the prechiasmatic area, the other two were the paraventricular organ (PVO) and infundibular nucleus (IN) in the postchiasmatic area. Each of them exhibited different ontogenetic changes. During larval development, TH-positive cell bodies were first detected in the PVO and IN at a premetamorphic stage. The number of immunoreactive cells increased rapidly in both loci as metamorphosis proceeded, although the two nuclei showed different growth profiles. By contrast, in the PRO, a very small number of immunoreactive cells were observed before the onset of the prometamorphic period. Although the number of immunoreactive neurons increased as metamorphosis progressed, early neurons were confined to the caudal area of the PRO (cPRO), the rostral area of the PRO (rPRO) being devoid of TH-positive cells. Immunoreactive TH neurons appeared in the rPRO for the first time at the end of meta-morphic climax. This timing coincided well with the development of TH-positive nerve endings in the pars intermedia (PI) and median eminence. In the second series of experiments, the embryonic primordium of the PRO was surgically extirpated from open neurulae to examine the effects of PRO-ectomy. In 75% of the operated animals, background adaptation was not observed, their dermal melanophores remained permanently dispersed even on the white background. Dopaminergic neurons in the rPRO and the immunoreactive nerve endings in the PI and median eminence were scarcely observed in these animals. It was concluded that the present data strongly support the hypothesis that rPRO is the center of white-background adaptation. 相似文献
3.
Frog melanophores rapidly change colour by dispersion or aggregation of melanosomes. A long‐term colour change exists where melanosomes are released from melanophores and transferred to surrounding skin cells. No in vitro model for pigment transfer exists for lower vertebrates. Frog melanophores of different morphology exist both in epidermis where keratinocytes are present and in dermis where fibroblasts dominate. We have examined whether release and transfer of melanosomes can be studied in a melanophore‐fibroblast co‐culture, as no frog keratinocyte cell line exists. Xenopus laevis melanophores are normally cultured in conditioned medium from fibroblasts and fibroblast‐derived factors may be important for melanophore morphology. Melanin was exocytosed as membrane‐enclosed melanosomes in a process that was upregulated by α‐melanocyte‐stimulating hormone (α‐MSH), and melanosomes where taken up by fibroblasts. Melanosome membrane‐proteins seemed to be of importance, as the cluster‐like uptake pattern of pigment granules was distinct from that of latex beads. In vivo results confirmed the ability of dermal fibroblasts to engulf melanosomes. Our results show that cultured frog melanophores can not only be used for studies of rapid colour change, but also as a model system for long‐term colour changes and for studies of factors that affect pigmentation. 相似文献
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5.
Abstract The aim of this work was to determine whether the neurogenic mechanisms which trigger LH release during the critical period in the afternoon of proestrus could be revealed during the diestrous period of the cycle. 相似文献
6.
Regina Celia Rodrigues da Paz William Frederick Swanson Eduardo Antunes Dias Cristina Harumi Adania Valquíria Hipplito Barnabe Renato Campanarut Barnabe 《Zoo biology》2005,24(3):247-260
Exogenous gonadotropins frequently are used to stimulate ovarian follicular growth and ovulation in mammalian species, including felids. However, repeated exogenous gonadotropin treatment can result in decreased ovarian responsiveness due to antibody formation. In this study, our objectives were to assess the effectiveness of alternating gonadotropin regimens on ovarian responses in ocelots and tigrinas, and investigate the humoral immune responses to these gonadotropins in each species. Females were treated four to six times with alternating equine chorionic gonadotropin (eCG)/human chorionic gonadotropin (hCG) and porcine follicle stimulating hormone (pFSH)/luteinizing hormone (pLH) regimens at 4‐month intervals. With each treatment, the females were evaluated laparoscopically to assess ovarian follicular development and recover oocytes from mature follicles. Blood was collected before each treatment and at laparoscopy. Overall, the ocelots averaged more (P<0.05) follicles and corpus luteum (CL) (6.8±0.8; mean±SEM) per stimulation than the tigrinas (2.3±0.4), but the percentage of mature oocytes (mean range=54–55%) did not differ (P<0.05). Within species, both gonadotropin regimens were equally effective (P>0.05) in inducing follicular growth and oocyte maturation. The total number of ovarian structures and oocyte maturation percentages did not decrease (P<0.05) in either species with sequential stimulations. Although the percentage of blood samples containing anti‐gonadotropin immunoglobulins increased (P<0.05) with sequential treatment, the presence of positive titers did not cause a decrease (P<0.05) in ovarian responsiveness. In summary, the female ocelots and tigrinas continued to respond to these alternating ovarian stimulation protocols after repeated use, despite the formation of anti‐gonadotropin antibodies in some of the females. These findings suggest that the use of alternating gonadotropin regimens may permit more intensive reproductive management of these endangered cat species for conservation. Zoo Biol 00:1–14, 2005. © 2005 Wiley‐Liss, Inc. 相似文献
7.
Gabriel E. Bertolesi Carrie L. Hehr Hayden Munn Sarah McFarlane 《Pigment cell & melanoma research》2016,29(6):688-701
Two biological processes regulate light‐induced skin colour change. A fast ‘physiological pigmentation change’ (i.e. circadian variations or camouflage) involves alterations in the distribution of pigment containing granules in the cytoplasm of chromatophores, while a slower ‘morphological pigmentation change’ (i.e. seasonal variations) entails changes in the number of pigment cells or pigment type. Although linked processes, the neuroendocrine coordination triggering each response remains largely obscure. By evaluating both events in Xenopus laevis embryos, we show that morphological pigmentation initiates by inhibiting the activity of the classical retinal ganglion cells. Morphological pigmentation is always accompanied by physiological pigmentation, and a melatonin receptor antagonist prevents both responses. Physiological pigmentation also initiates in the eye, but with repression of melanopsin‐expressing retinal ganglion cell activity that leads to secretion of alpha‐melanocyte‐stimulating hormone (α‐MSH). Our findings suggest a model in which eye photoperception links physiological and morphological pigmentation by altering α‐MSH and melatonin production, respectively. 相似文献
8.
During evaluation of follicle-stimulating hormone-beta (FSHB) expression in anterior pituitary glands by an RNase protection assay (RPA), the expected fragment of 205 nucleotides at positions 759-963 was not detected in one boar that had moderate plasma and pituitary FSH concentrations. After subcloning and sequencing, mRNA from this boar lacked an 11-bp fragment (5'-CATTTGGAAAC-3') at nucleotide positions 807-817 of the 3'-untranslated region (3'-UTR, D allele). Wild-type FSHB (WT allele) was present in pituitary RNA and genomic DNA in both Meishan (MS) and White Composite (WC) pigs; whereas the D allele was present only in MS pigs (P < 0.01; 5/6 MS vs. 0/6 WC). Also, we found the D allele in five other Chinese breeds but absent in ten American Landrace, 11 Yorkshire and 17 Berkshire pigs. Additionally, the D allele had one silent nucleotide change in the coding region plus six, single nucleotide changes in the 3'-UTR. 相似文献
9.
目的:分析大鼠卵泡刺激素(FSH)分泌的受体后信号转导机制。方法:将促性腺激素(GTH)细胞用毛喉素(FSK)或腺苷酸环化酶抑制剂SQ22536处理后,用促性腺激素释放激素脉冲刺激,再用酶联免疫吸附法检测其FSH分泌量,并与空白对照组比较。结果:FSK能显著提高GTH细胞中环磷酸腺苷(cAMP)含量,SQ22536能显著降低GTH细胞中的cAMP含量,FSK和SQ22536都不会影响GTH细胞的蛋白激酶C活性,GTH细胞cAMP含量的变化对FSH分泌的影响不显著。结论:cAMP-PKA(蛋白激酶A)不是FSHβ亚基分泌的受体后信号转导途径。 相似文献
10.
Mojtaba Ameli Maryam Moghimian Farzaneh Saeb Elham Bashtani Majid Shokoohi Ramin Salimnejad Hossein Abtahi 《Molecular reproduction and development》2019,86(6):738-748
The purpose of this study was to investigate the effect of clomiphene citrate and human chorionic gonadotropin (HCG) on the structural changes, as well as the evaluation of the expression of cation channel sperm‐associated protein 1 (CatSper1), cation channel sperm‐associated protein 2 (CatSper2), luteinizing hormone/choriogonadotropin receptor (LHCGR), and steroidogenic factor 1 (SF1) genes in testicular tissue of rats. All rats divided into five groups as follows; G1 as the control group that received normal saline, G2 received olive oil, G3 received 100 IU/kg HCG, G4 received 5 mg/kg clomiphene citrate, and G5 received 5 mg/kg clomiphene citrate and 100 IU/kg HCG. At the end of the experiment period, Day 56, blood samples were taken and the serum was isolated. Then, histomorphometric analysis, hormonal assess, and real‐time polymerase chain reaction to measure the expression of CatSper1, CatSper2, LHCGR, and SF1 genes were performed. The results showed that the concentrations of testosterone, follicle‐stimulating hormone, and luteinizing hormone were decreased in the G4 group, whereas these parameters were increased in the G3 group. A comparison of the sperm quality indicated a significant reduction in the quality of sperm cells in the G4 group compared with other groups. The quality of sperm was significantly enhanced in the G3 and G5 groups in comparison with the G1 group. Also, our findings demonstrated that the expression of CatSper1, CatSper2, LHCGR, and SF1 genes were significantly elevated in the G3 group when compared with other experimental groups. According to the obtained results, it seems that clomiphene citrate reduces the process of spermatogenesis and the detrimental impacts of this compound would be neutralized by the administration of HCG. 相似文献
11.
H.E. Todd S.E. Shideler L.S. Laughlin J.W. Overstreet C.R. Pohl W. Byrd B.L. Lasley 《American journal of primatology》1999,48(2):135-151
An enzyme‐linked immunosorbent assay (ELISA) for human urinary beta follicle‐stimulating hormone (FSH) subunit was validated for use in the laboratory macaque (Macaca mulatta and Macaca fasicularis). This ELISA is based on the dissociation of the FSH heterodimer in urine and the subsequent measurement of the beta subunit as a representation of total urinary FSH. This assay was then used to describe the gonadotropin escape following ovarian senescence in post‐menopausal macaques. In addition, the assay was used to observe the impact of an acute stressor on the pituitary‐gonadal axis and how the impact of this stressor varies when experienced at different stages of the menstrual cycle. The study design involved the measurement of ovarian steroids and FSH in urine collected daily during a period of time when animals experienced a well‐defined event on two occasions consisting of capture, restraint, and anesthesia. This unique study design was made possible by the ability to monitor both ovarian and pituitary function in the absence of confounding daily captures and restraint for blood collection. There was a high correlation between urinary FSH measured in macaques with the beta FSH subunit ELISA and serum FSH measured in paired blood samples by radioimmunoassay (n=39, r2=0.878, P<0.001) and the composite urinary FSH profile obtained from normal, pre‐menopausal macaques exhibited the expected dynamics with a transient rise of FSH during the luteal‐follicular transition as well as an acute rise of FSH at mid‐cycle. This pattern was lost in castrate and post‐menopausal monkeys in which FSH levels were significantly increased (P<0.0001) above those of intact males and young females, respectively. In the stress study, we found that stressors occurring during the luteal‐follicular transition not only resulted in acute perturbations of FSH but also led to abnormalities in the subsequent menstrual cycle in 50% of the cases. Am. J. Primatol. 48:135–151, 1999. © 1999 Wiley‐Liss, Inc. 相似文献
12.
Ji Hye Kim Dong Hyun Kim Kyung Mun Cho Kyoung Heon Kim Nam Joo Kang 《Journal of cellular biochemistry》2018,119(9):7643-7656
13.
Fish can change their skin and eye colour for background matching and signalling. Males of Gasterosteus aculeatus develop ornamental blue eyes and a red jaw during the reproductive season, colours that are further enhanced during courtship. Here, the effects of different hormones on physiological colour changes in the eyes and jaws of male and female G. aculeatus were investigated in vitro. In an in vivo experiment, G. aculeatus were injected with a receptor blocker of a pivotal hormone (noradrenaline) that controls colour change. In males, noradrenaline had aggregating effects on melanophore and erythrophore pigments resulting in blue eyes and a pale jaw, whereas melanocyte‐concentrating hormone (MCH) and melatonin resulted in a pale jaw only. When noradrenalin was combined with melanocyte stimulating hormone (MSH) or prolactin, the jaw became red, while the eyes remained blue. In vivo injection of yohimbine, an alpha‐2 adrenoreceptor blocker, resulted in dispersion of melanophore pigment in the eyes and inhibited the blue colouration. Altogether, the data suggest that noradrenalin has a pivotal role in the short‐term enhancement of the ornamental colouration of male G. aculeatus, potentially together with MSH or prolactin. This study also found a sex difference in the response to MCH, prolactin and melatonin, which may result from different appearance strategies in males, versus the more cryptic females. 相似文献
14.
Summary The skin of the lizard, Anolis carolinensis, changes rapidly from bright green to a dark brown color in response to melanophore stimulating hormone (MSH). Chromatophores responsible for color changes of the skin are xanthophores which lie just beneath the basal lamina containing pterinosomes and carotenoid vesicles. Iridophores lying immediately below the xanthophores contain regularly arranged rows of reflecting platelets. Melanophores containing melanosomes are present immediately below the iridophores. The ultrastructural features of these chromatophores and their pigmentary organelles are described. The color of Anolis skin is determined by the position of the melanosomes within the melanophores which is regulated by MSH and other hormones such as norepinephrine. Skins are green when melanosomes are located in a perinuclear position within melanophores. In response to MSH, they migrate into the terminal processes of the melanophores which overlie the xanthophores above, thus effectively preventing light penetration to the iridophores below, resulting in skins becoming brown. The structural and functional characteristics of Anolis chromatophores are compared to the dermal chromatophore unit of the frog.This study was supported in part by GB-8347 from the National Science Foundation.Contribution No. 244, Department of Biology, Wayne State University.The authors are indebted to Dr. Joseph T. Bagnara for his encouragement during the study and to Dr. Wayne Ferris for his advice and the use of his electron microscope laboratory. 相似文献
15.
Hashimoto S Kimura K Kuramochi T Aoyagi K Hirako M Kawaguchi M Iwata H Hirao M Kitada K Hirasawa K Ueda M 《Molecular reproduction and development》2007,74(9):1208-1212
Aluminum hydroxide gel (Al-gel), which is used as an adjuvant, can absorb macromolecules. We investigated the applicability of Al-gel to the sustained release of follicle-stimulating hormone (FSH) as a simplified method of superovulation (SOV) in rabbits. The responsiveness of rabbits to SOV by a single injection of FSH dissolved in Al-gel suspension (3.2 mg Al/ml) and in 10% (w/v) polyvinylpyrrolidone (PVP), and by multiple injections of FSH in saline was examined. The numbers of total and fertilized eggs recovered from rabbits treated with FSH in Al-gel (40.5 and 26.3, respectively) were similar to multiple injections (47.4 and 28.6, respectively) and were significantly greater (P < 0.05) than single injection of FSH with PVP (17.3 and 11.5, respectively). We also compared the plasma FSH levels of rabbits which were induced SOV by multiple or a single injection of Al-gel. Al-gel provided sustained release of FSH to the blood stream at a high enough dose for SOV. Moreover, the developmental competence of the pups of DNA-injected embryos from rabbits treated with a single injection of FSH mixed with Al-gel (18%) was similar to that of DNA-injected embryos, recovered from rabbits treated with FSH dissolved in saline (21%). Two transgenic pups were obtained from embryos recovered from rabbits by a single injection of FSH with Al-gel. These results indicate that a single injection of FSH with Al-gel is an effective method for SOV of rabbit and that this technique is applicable to research requiring large numbers of rabbit embryos such as the production of transgenic rabbits. 相似文献
16.
Tayze T. Antunes AnneMarie Gagnon Andrea Bell Alexander Sorisky 《Obesity (Silver Spring, Md.)》2005,13(12):2066-2071
17.
The changes in serum gonadotrophins in male hamsters following one injection of 15 μg luteinizing hormone releasing hormone (LHRH) (Group A) were compared with those following the last injection of LHRH in animals receiving an injection approximately every 12 hr for 4 days (Group B) or 12 days (Group C). Peak follicle stimulating hormone (FSH) levels (ng/ml) were 1776±218 (Group A), 2904±346 (Group B), and 4336±449 (Group C). Peak luteinizing hormone (LH) values (ng/ml) were 1352±80 (Group A), 410±12 (Group B), and 498±53 (Group C). Serum FSH:LH ratios, calculated from the concentrations measured 16 hr after the last LHRH injections, were higher in Groups B and C than in Group A. Similar injections of LHRH (100 ng or 15 μg/injection) for 6 days elevated the serum FSH:LH ratio in intact males. Five such LHRH injections (100 ng/injection) blunted the rise in serum LH in orchidectomized hamsters. Direct effects of LHRH on gonadotrophin secretory dynamics or altered brain-pituitary-testicular interactions may alter the ratio of FSH to LH in the hamster. 相似文献
18.
A. N. Elias A. F. Wilson M. R. Pandian F. J. Rojas R. Kayaleh S. C. Stone N. James 《European journal of applied physiology and occupational physiology》1993,66(4):357-361
Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone, testosterone (T) and melatonin were measured in seven physically active male volunteers after exercise on a treadmill using the Bruce protocol. Measurements were made on blood samples obtained before exercise, within 30 s after exercise, at 15 min after exercise, and subsequently at 30-min intervals after exercise for a total duration of 180 min. Serum LH concentration fell from a peak post-exercise level of 15.7 (4.7) IU·l–1 [mean (SD)] to a nadir of 10.3 (2.4) IU·l–1 (P<0.004). Nadir values in individual volunteers were seen between 60 and 150 min after exercise. This fall in serum LH was paralleled by a similar fall in the concentration of serum T. Serum melaonin concentrations did not change significantly after exercise. It is concluded that melatonin, despite is reported anti-gonadotropic properties, does not play a role in the depression of serum LH after acute strenuous exercise in physically active males 相似文献
19.
Tomohisa Hirobe 《Pigment cell & melanoma research》2005,18(1):2-12
Melanocytes characterized by the activities of tyrosinase, tyrosinase‐related protein (TRP)‐1 and TRP‐2 as well as by melanosomes and dendrites are located mainly in the epidermis, dermis and hair bulb of the mammalian skin. Melanocytes differentiate from melanoblasts, undifferentiated precursors, derived from embryonic neural crest cells. Because hair bulb melanocytes are derived from epidermal melanoblasts and melanocytes, the mechanism of the regulation of the proliferation and differentiation of epidermal melanocytes should be clarified. The regulation by the tissue environment, especially by keratinocytes is indispensable in addition to the regulation by genetic factors in melanocytes. Recent advances in the techniques of tissue culture and biochemistry have enabled us to clarify factors derived from keratinocytes. Alpha‐melanocyte‐stimulating hormone, adrenocorticotrophic hormone, basic fibroblast growth factor, nerve growth factor, endothelins, granulocyte‐macrophage colony‐stimulating factor, steel factor, leukemia inhibitory factor and hepatocyte growth factor have been suggested to be the keratinocyte‐derived factors and to regulate the proliferation and/or differentiation of mammalian epidermal melanocytes. Numerous factors may be produced in and released from keratinocytes and be involved in regulating the proliferation and differentiation of mammalian epidermal melanocytes through receptor‐mediated signaling pathways. 相似文献
20.
Estrogen deficiency as the sole factor underlying post‐menopausal osteoporosis was challenged, in light of reports that both follicular stimulation hormone (FSH) receptor and FSHβ knockout mice were resistant to bone loss, suggesting a detrimental role for FSH. We assessed whether lowering FSH levels by gonadotropin realizing (GnRH) analog decapeptyl in ovariectomized female rats (OVX) affects bone. Wistar‐derived 25 days old OVX female rats were injected for 10 weeks with estradiol‐17β (E2), with GnRH analog (decapeptyl) or with both. FSH and luteinizing hormone (LH) serum levels were markedly increased in OVX rats, with smaller growth plates with disrupted architecture; heavy infiltration of bone marrow with numerous adipocytes and reduced thickness of cortical bone. In OVX rats treated with E2, FSH, and LH levels were intermediate, the tibia was similar to that of intact rats, but there was reduced thickness of cortical bone. In decapeptyl treated OVX rats, FSH and LH levels were suppressed, the organization of growth plate and the trabecular bone were disrupted, and there were fewer proliferative and chondroblastic cells and a large adipocytes population in bone marrow, but an increased trabecular bone volume (TBV). In the E2 + decapeptyl treatment, FSH and LH levels were suppressed, with partially restored growth plate architecture and improved TBV. In conclusion, E2 deficiency is the dominant factor impairing bone loss in OVX and concomitant changes in FSH/LH levels achieved by decapeptyl have some modulating, though complex role in this setting. The role of high FSH levels in post‐menopausal bone loss requires further investigation using combined sub‐optimal doses of the different hormones. J. Cell. Biochem. 112: 128–137, 2011. © 2010 Wiley‐Liss, Inc. 相似文献