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1.
J Diabetes Res ; 2021: 5581349, 2021.
Article in English | MEDLINE | ID: mdl-34485532

ABSTRACT

OBJECTIVES: Previous studies reported that overweight older adults had a lower mortality after cardiovascular diseases attack, indicating being thinner might not always be better. However, there is an ongoing debate about what is the optimal range of body mass index (BMI) for the aged population. We aimed to evaluate the value of BMI for the prediction of incident diabetes mellitus (DM) in the Chinese elderly population. METHODS: A total number of 6,911 Chinese elderly people (4,110 men and 2,801 women, aged 71 ± 6.0 years) were included in this cohort study. BMI was measured at baseline (Jan 1, 2014, to Dec 31, 2014). All the participants were further classified into six groups: <18.5 kg/m2, 18.5 to <22.5 kg/m2, 22.5 to <25.0 kg/m2, 25.0 to <27.5 kg/m2, 27.5 to <30.0 kg/m2, and ≥30.0 kg/m2. Fasting blood glucose (FBG) and glycated hemoglobin A1c (HbA1c) were annually measured during follow-up (Jan 1, 2015-May 31, 2019). DM was confirmed if either FBG ≥ 7.0 mmol/L or HbA1c ≥ 6.5%. We used the Cox proportional hazard regression model to evaluate the association between BMI and the prediction of incident DM. RESULTS: Comparing individuals with a BMI range of 18.5 to <22.5 kg/m2 (reference), the hazard ratio for incident DM was 2.13 (95% CI: 1.54~2.95), 2.14 (95% CI: 1.53~3.00), 3.17 (95% CI: 2.19~4.59), 3.15 (95% CI: 1.94~5.09), and 3.14 (95% CI: 1.94~5.09) for the group with a BMI range of 22.5 to <25.0 kg/m2, 25.0 to <27.5 kg/m2, 27.5 to <30.0 kg/m2, and ≥30.0 kg/m2 after adjusting for baseline age, sex, blood pressure, lipid profiles, and eGFR (P trend < 0.001), after adjusting for the abovementioned confounders. The association tended to be closer in men and young participants, compared with their counterparts. CONCLUSIONS: High BMI was associated with a high risk of developing DM in the Chinese aged population. Thus, it is optimal for the aged population to maintain their body weight within a reasonable range to prevent chronic diseases.


Subject(s)
Body Mass Index , Diabetes Mellitus/epidemiology , Obesity/epidemiology , Age Factors , Aged , Biomarkers/blood , Blood Glucose/analysis , China/epidemiology , Diabetes Mellitus/blood , Diabetes Mellitus/diagnosis , Female , Glycated Hemoglobin/metabolism , Humans , Incidence , Male , Obesity/diagnosis , Prognosis , Risk Assessment , Risk Factors , Time Factors
2.
Nutr Metab Cardiovasc Dis ; 29(3): 260-267, 2019 03.
Article in English | MEDLINE | ID: mdl-30642789

ABSTRACT

BACKGROUND AND AIMS: We evaluated the association between parental obesity and their children's obesity parameters [e.g., percentage of body fat (PBF)] over time. METHODS AND RESULTS: The study included 2066 Chinese parents-children trios (n = 1001 girls and 1065 boys, aged 6-14 years). Children's height, weight, waist circumference (WC) and PBF (bioelectrical impedance analysis) were annually assessed from 2014 (baseline) to 2016. Information on parental height and body weight, and children's diet and physical activity was collected in 2014. The association between parental obesity and changes in their children's PBF during follow-up was analyzed using a mixed effects model. We also examined changes in children's BMI and WC in secondary analyses. Baseline mean BMI, WC, and PBF for children were 17.6 ± 3.5 kg/m2, 60.5 ± 9.6 cm, and 16.6 ± 6.5%, respectively. We observed that maternal, but not paternal, obesity was associated with a greater increase in children's PBF during the follow-up. An adjusted mean difference in annual increase of PBF was 0.41% [95% confidence interval (CI): 0.01%, 0.84%] for children with obese mothers, compared with those with normal-weight mothers. Both maternal and paternal obesity was associated with a greater increase in their children's BMI and WC (p trend<0.01 for both); however, the associations were stronger in mother-children pairs than those in father-children pairs. CONCLUSIONS: Maternal obesity was associated with a greater increase in PBF in Chinese school-aged children.


Subject(s)
Child of Impaired Parents , Mothers , Obesity/epidemiology , Pediatric Obesity/epidemiology , Adiposity , Adolescent , Age Factors , Body Mass Index , Child , China/epidemiology , Electric Impedance , Fathers , Female , Humans , Life Style , Male , Obesity/diagnosis , Obesity/physiopathology , Pediatric Obesity/diagnosis , Pediatric Obesity/physiopathology , Prevalence , Risk Factors , Sex Factors , Time Factors , Waist Circumference
3.
Nutr Metab Cardiovasc Dis ; 28(10): 1061-1066, 2018 10.
Article in English | MEDLINE | ID: mdl-30207269

ABSTRACT

BACKGROUND AND AIMS: We prospectively examined the association between three adiposity indices, including body mass index (BMI), waist circumference (WC), and percentage of body fat (PBF), and risk of hypertension in normal-weight Chinese children. METHODS AND RESULTS: The current study included 1526 (713 boys and 813 girls) normal-weight Chinese children (age 6-14 years old), who were free of hypertension at baseline (2014). Heights, body weight, WC, and PBF (estimated by bioelectrical impedance analysis) were measured at the baseline. Blood pressure was repeatedly measured in 2014, 2015 and 2016. Hypertension was defined as either high systolic blood pressure and/or high diastolic blood pressure, according to age- and sex-specific 95th percentile for Chinese children. We used Cox proportional hazards model to calculate the association between exposures and hypertension. We identified 88 incident hypertension cases during two years of follow up. High BMI was associated with high risk of developing hypertension after adjusting for potential confounders. The adjusted hazard ratio for hypertension was 2.88 (95% CI: 1.24, 6.69) comparing two extreme BMI quartiles. Each SD increase of BMI (≈1.85 kg/m2) was associated with a 32% higher likelihood to developing hypertension (Hazard ratio = 1.32; 95% CI: 1.003, 1.73). In contrast, we did not find significant associations between WC or PBF and higher hypertension risk (p-trend >0.2 for both). CONCLUSION: High BMI, but not WC and PBF, was associated with high risk of hypertension in normal-weight Chinese children.


Subject(s)
Adiposity , Blood Pressure , Body Mass Index , Hypertension/epidemiology , Hypertension/physiopathology , Waist Circumference , Adolescent , Age Factors , Child , China/epidemiology , Female , Humans , Hypertension/diagnosis , Incidence , Male , Prospective Studies , Risk Assessment , Risk Factors
4.
Eur Rev Med Pharmacol Sci ; 22(4): 943-949, 2018 02.
Article in English | MEDLINE | ID: mdl-29509242

ABSTRACT

OBJECTIVE: Cervical cancer is the second popular female specific malignant tumors. Long-strand non-coding RNA (lncRNA) GAS5 (Growth Arrest Specific 5) participates in pathological processes of various malignant tumors. This study aimed at investigating the correlation between lncRNA GAS5 expression and prognosis of cervical cancer patients. PATIENTS AND METHODS: Cancer tissues were collected from 48 cervical cancer patients. GAS5 expression in cervical cancer cells was determined by qRT-PCR and in situ hybridization (ISH). The correlation between GAS5 expression and pathological parameters of patients was analyzed. Cervical cancer cell line HeLa was used as the in vitro model, RNA interference approach was adopted to suppress lnc-RNA GAS5 expression. MTT assay was employed to analyze cell proliferation potency. Transwell assay was conducted to analyze the cell migration potency, and tumor cell invasion was measured. RESULTS: qRT-PCR and ISH results showed that GAS5 expression in cervical cancer tissues was significantly inhibited compared to that in adjacent tissues (p<0.05). GAS5 expression was correlated with FIGO stage and metastatic tumor parameters of cervical cancer patients (p<0.01). RNA interference data showed that the down-regulation of GAS5 significantly enhanced cell proliferation and invasion potency (p<0.05). CONCLUSIONS: GAS5 is down-regulated in cervical cancer cells, and this is probably related to patient clinical stage and tumor invasion or metastasis. The regulatory role of GAS5 on cell proliferation provides the academic basis for the future therapy of cervical cancer.


Subject(s)
Gene Expression Regulation, Neoplastic , RNA, Long Noncoding/biosynthesis , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/metabolism , Adult , Apoptosis/physiology , Cell Line, Tumor , Cell Movement/physiology , Cell Proliferation/physiology , Female , HeLa Cells , Humans , Middle Aged , Prognosis , RNA Interference/physiology , RNA, Long Noncoding/genetics , Uterine Cervical Neoplasms/genetics
5.
Curr Mol Med ; 17(1): 70-78, 2017.
Article in English | MEDLINE | ID: mdl-28231752

ABSTRACT

HoxD10 gene plays a critical role in cell proliferation in the process of tumor development. However, the protein expression level and the function of HoxD10 in prostate cancer remain unknown. Using tissue microarray, we demonstrate that the protein expression of HoxD10 is commonly decreased in prostate cancer tissues (n = 92) compared to adjacent benign prostate tissues (n = 77). Functionally, knockdown of HoxD10 resulted in significant promotion of prostate cancer cell proliferation. Moreover, knockdown of HoxD10 strikingly stimulated prostate tumor growth in a mouse xenograft model. We also found a significant association between decreased immunohistochemical staining of HoxD10 expression and higher Gleason score (P = 0.031) and advanced clinical pathological stage (P = 0.011). An analysis of the Taylor database revealed that decreased HoxD10 expression predicted worse biochemical recurrence (BCR)-free survival of PCa patients (P = 0.005) and the multivariate analyses further supported that HoxD10 might be an independent predictor for BCR-free survival (P = 0.027). Collectively, our data suggest that the loss of HoxD10 function is common and may thus result in a progressive phenotype in PCa. HoxD10 may function as a biomarker that differentiates patients with BCR disease from the ones that are not after radical prostatectomy, implicating its potential as a therapeutic target.


Subject(s)
Biomarkers, Tumor , Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Phenotype , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/genetics , Transcription Factors/genetics , Aged , Animals , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Disease Models, Animal , Disease Progression , Heterografts , Homeodomain Proteins/metabolism , Humans , Male , Mice , Middle Aged , Neoplasm Grading , Neoplasm Metastasis , Neoplasm Staging , Prognosis , Prostatic Neoplasms/mortality , RNA, Small Interfering/genetics , Transcription Factors/metabolism
6.
Mol Biol (Mosk) ; 48(4): 682-6, 2014.
Article in Russian | MEDLINE | ID: mdl-25842852

ABSTRACT

The aim of the study was to explore the interactions of human papilloma virus 16 (HPV16) E2 protein and Daxx. The location or co-localization of PML and E2 with Daxx in Caski cells was observed by indirect immunofluorescence test. The interaction of E2 and Daxx was analyzed by co-immunoprecipitation, Western-blot and yeast-two hybrid assay. In Caski cells the fluorescence of Daxx or PML was mainly distributed in the cytoplasm or nucleus, respectively, and in the align image their signals did not overlapped. However, when the red signal of HPV16 E2 and the green signal of Daxx in cyto- plasm of Caski cells were merged, the yellow signals appeared. The yeast co-transformed with pGBKT7/Daxx and pGADT7/E2 or pGADT7/E2 TAD can grow onto SD/-Trp-Leu-His and SD/-Trp-Leu-His-Ade plates. So Daxx wasn't co-located with PML but with HPV16 E2 mainly in the cytoplasm of Caski cells. On the base of the results one can propose that HPV16 E2, in particularly its transcription-activity domain (TAD), interacts with Daxx.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , DNA-Binding Proteins/metabolism , Nuclear Proteins/metabolism , Oncogene Proteins, Viral/metabolism , Adaptor Proteins, Signal Transducing/genetics , Blotting, Western , Cell Line , Cell Nucleus/metabolism , Co-Repressor Proteins , Cytoplasm/metabolism , DNA-Binding Proteins/genetics , Humans , Immunoprecipitation , Molecular Chaperones , Mutation , Nuclear Proteins/genetics , Oncogene Proteins, Viral/genetics , Promyelocytic Leukemia Protein , Transcription Factors/metabolism , Tumor Suppressor Proteins/metabolism , Two-Hybrid System Techniques
7.
Biochemistry ; 40(20): 6164-79, 2001 May 22.
Article in English | MEDLINE | ID: mdl-11352754

ABSTRACT

In vitro mutagenesis of the mouse melanocortin-4 receptor (mMC4R) has been performed, based upon homology molecular modeling and previous melanocortin receptor mutagenesis studies that identified putative ligand-receptor interactions. Twenty-three mMC4 receptor mutants were generated and pharmacologically characterized using several melanocortin-based ligands [alpha-MSH, NDP-MSH, MTII, DNal (1')(7)-MTII, Nal(2')(7)-MTII, SHU9119, and SHU9005]. Selected mutant receptors possessing significant differences in the melanocortin-based peptide agonist and/or antagonist pharmacology were further evaluated using the endogenous antagonist agouti-related protein fragment hAGRP(83-132) and hAGRP(109-118) molecules. These studies of the mouse MC4R provide further experimental data suggesting that the conserved melanocortin receptor residues Glu92 (TM2), Asp114 (TM3), and Asp118 (TM3) (mouse MC4R numbering) are important for melanocortin-based peptide molecular recognition. Additionally, the Glu92 and Asp118 mMC4R residues are important for molecular recognition and binding of AGRP(83-132). We have identified the Phe176 (TM4), Tyr179 (TM4), Phe254 (TM6), and Phe259 (TM6) receptor residues as putatively interacting with the melanocortin-based ligand Phe(7) by differences between alpha-MSH and NDP-MSH agonist potencies. The Glu92, Asp118, and Phe253 mMC4R receptor residues appear to be critical for hAGRP(83-132) molecular recognition and binding while Phe176 appears to be important for functional antagonism of AGRP(83-132) and AGRP(109-118) but not molecular recognition. The Phe253 mMC4R residue appears to be important for AGRP(83-132) molecular recognition and general mMC4 receptor stimulation. The Phe254 and Phe259 mMC4R amino acids may participate in the differentiation of agonist versus antagonist activity of the melanocortin-based peptide antagonists SHU9119 and SHU9005, but not AGRP(83-132) or AGRP(109-118). The Met192 side chain when mutated to a Phe results in a constitutively active mMC4R that does not effect agonist ligand binding or potency. Melanocortin-based peptides modified at the 7 position of MTII with DPhe, DNal(1'), Nal(2'), and DNal(2') have been pharmacologically characterized at these mutant mouse MC4Rs. These data suggest a revised hypothesis for the mechanism of SHU9119 antagonism at the MC4R which may be attributed to the presence of a "bulky" naphthyl moiety at the 7 position (original hypothesis), and additionally that both the stereochemistry and naphthyl ring position (2' versus 1') are important for positioning of the ligand Arg(8) residue with the corresponding mMC4R amino acids.


Subject(s)
Mutagenesis, Site-Directed , Peptides/pharmacology , Proteins/metabolism , Receptors, Corticotropin/chemistry , Receptors, Corticotropin/metabolism , Receptors, Peptide/chemistry , Receptors, Peptide/metabolism , alpha-MSH/agonists , Agouti-Related Protein , Amino Acid Sequence , Animals , Cell Line , Humans , Intercellular Signaling Peptides and Proteins , Ligands , Lysine/genetics , Melanocyte-Stimulating Hormones/pharmacology , Mice , Molecular Sequence Data , Peptide Fragments/chemical synthesis , Peptide Fragments/metabolism , Peptide Fragments/pharmacology , Peptides/chemical synthesis , Peptides/metabolism , Phenylalanine/genetics , Protein Binding/genetics , Proteins/chemistry , Proteins/pharmacology , Receptor, Melanocortin, Type 4 , Receptors, Corticotropin/antagonists & inhibitors , Receptors, Corticotropin/genetics , Receptors, Peptide/antagonists & inhibitors , Receptors, Peptide/genetics , Serine/genetics , Structure-Activity Relationship , Transfection , alpha-MSH/analogs & derivatives , alpha-MSH/antagonists & inhibitors , alpha-MSH/chemistry , alpha-MSH/metabolism , alpha-MSH/pharmacology
8.
Peptides ; 21(5): 683-9, 2000 May.
Article in English | MEDLINE | ID: mdl-10876051

ABSTRACT

Agouti-related protein (AGRP) is a naturally occurring antagonist of the brain melanocortin receptors (MC3R and MC4R) and is physiologically implicated as participating in feeding behavior and energy homeostasis. The human AGRP decapeptide Yc[CRFFNAFC]Y has been previously reported as binding to the human MC3 and MC4 receptors and antagonizing the MC4 receptor. We have synthesized this decapeptide and pharmacologically characterized it at the murine melanocortin receptors and found it to possess MC4R antagonist activity (pA(2) = 6.8) and, unexpectedly, MC1R agonist activity (EC(50) = 2.89 microM). This study characterizes the first AGRP-based peptide agonist at the melanocortin receptors.


Subject(s)
Peptide Fragments/pharmacology , Receptor, Melanocortin, Type 3 , Receptors, Corticotropin/agonists , Agouti-Related Protein , Amino Acid Sequence , Animals , Cell Line , Humans , Mice , Molecular Mimicry , Molecular Sequence Data , Peptide Fragments/chemistry , Receptors, Melanocortin , Sequence Homology, Amino Acid
9.
Life Sci ; 45(11): 1001-8, 1989.
Article in English | MEDLINE | ID: mdl-2552241

ABSTRACT

Binding characteristics of a new, conformationally constrained, halogenated enkephalin analogue, [3H]-[D-penicillamine2, pCl-Phe4, D-penicillamine5]enkephalin ([3H]pCl-DPDPE), were determined using homogenized rat brain tissue. Saturation binding studies at 25 degrees C determined a dissociation constant (Kd) of 328 +/- 27.pM and a receptor density (Bmax) of 87.2 +/- 4.2 fmol/mg protein. Kinetic studies demonstrated biphasic association for [3H]pCl-DPDPE, with association rate constants of 5.05 x 10(8) +/- 2.5 x 10(8) and 0.147 +/- 10(8) +/- 0.014 x 10(8) M-1 min-1. Dissociation was monophasic with a dissociation rate constant of 2.96 x 10(-3) +/- 0.25 x 10(-3) min-1. The average Kd values determined by these kinetic studies were 8.4 +/- 2.7 pM and 201 +/- 4 pM. Competitive inhibition studies demonstrated that [3H]pCl-DPDPE has excellent selectively for the delta opioid receptor. [3H]pCl-DPDPE binding was inhibited by low concentrations of ligands selective for delta opioid receptor relative to the concentrations required by ligands selective for mu and kappa sites. These data show that [3H]pCl-DPDPE is a highly selective, high affinity ligand which should be useful in characterizing the delta opioid receptor.


Subject(s)
Enkephalins/metabolism , Receptors, Opioid/metabolism , Animals , Binding, Competitive , Brain/metabolism , Enkephalin, D-Penicillamine (2,5)- , Kinetics , Male , Naltrexone/pharmacology , Rats , Rats, Inbred Strains , Receptors, Opioid/drug effects
10.
J Pharmacol Exp Ther ; 248(1): 73-80, 1989 Jan.
Article in English | MEDLINE | ID: mdl-2563293

ABSTRACT

The cyclic, conformationally restricted octapeptide [3H]-[H-D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2] ([3H]CTOP) was synthesized and its binding to mu opioid receptors was characterized in rat brain membrane preparations. Association rates (k+1) of 1.25 x 10(8) M-1 min-1 and 2.49 x 10(8) M-1 min-1 at 25 and 37 degrees C, respectively, were obtained, whereas dissociation rates (k-1) at the same temperatures were 1.93 x 10(-2) min-1 and 1.03 x 10(-1) min-1 at 25 and 37 degrees C, respectively. Saturation isotherms of [3H]CTOP binding to rat brain membranes gave apparent Kd values of 0.16 and 0.41 nM at 25 and 37 degrees C, respectively. Maximal number of binding sites in rat brain membranes were found to be 94 and 81 fmol/mg of protein at 25 and 37 degrees C, respectively. [3H]CTOP binding over a concentration range of 0.1 to 10 nM was best fit by a one site model consistent with binding to a single site. The general effect of different metal ions and guanyl-5'-yl-imidodiphosphate on [3H]CTOP binding was to reduce its affinity. High concentrations (100 mM) of sodium also produced a reduction of the apparent mu receptor density. Utilizing the delta opioid receptor specific peptide [3H]-[D-Pen2,D-Pen5]enkephalin, CTOP appeared to be about 2000-fold more specific for mu vs. delta opioid receptor than naloxone. Specific [3H]CTOP binding was inhibited by a large number of opioid or opiate ligands.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Receptors, Opioid/metabolism , Somatostatin/analogs & derivatives , Animals , Brain/metabolism , Endorphins/pharmacology , Enkephalin, D-Penicillamine (2,5)- , Enkephalins/metabolism , In Vitro Techniques , Kinetics , Magnesium/pharmacology , Male , Rats , Rats, Inbred Strains , Receptors, Opioid, mu , Sodium/pharmacology , Somatostatin/metabolism , Temperature , Tritium
11.
Neurosci Lett ; 80(2): 121-6, 1987 Sep 23.
Article in English | MEDLINE | ID: mdl-2960918

ABSTRACT

Binding sites for the vasopressin (VP) antagonist d(CH2)5Tyr(Me)VP, were located in various brain areas (e.g. the lateral septum, amygdala, choroid plexus and nucleus of the solitary tract) using light microscopic autoradiography. A number of areas (e.g. suprachiasmatic and arcuate nucleus, pineal gland) which previously showed no VP binding were labelled in the present study. The olfactory nucleus and ventromedial hypothalamic nucleus were not labelled. It therefore appears that d(CH2)5Tyr(Me)VP is capable of discriminating between VP and oxytocin binding sites and a more sensitive means of detecting VP binding sites than VP alone.


Subject(s)
Arginine Vasopressin/analogs & derivatives , Binding Sites , Brain/metabolism , Kidney/metabolism , Pituitary Gland/metabolism , Receptors, Angiotensin/analysis , Animals , Arginine Vasopressin/metabolism , Autoradiography , In Vitro Techniques , Male , Rats , Rats, Inbred Strains , Receptors, Angiotensin/metabolism , Receptors, Vasopressin , Vasopressins/antagonists & inhibitors , Vasopressins/metabolism
12.
Life Sci ; 38(5): 443-52, 1986 Feb 03.
Article in English | MEDLINE | ID: mdl-3945171

ABSTRACT

Binding sites for the vasopressin metabolite peptide, (AVP4-9), were detected in the rat brain. These binding sites were present in the hilus of the hippocampal formation, superior and inferior colliculus, pontine reticular nuclei, brainstem nuclei, lateral mammillary nucleus, choroid plexus and subfornical organ. The distribution of AVP4-9 binding sites was distinct from that of the parent peptide (1-3). This distinction was apparent in both the regional and intra-regional distribution.


Subject(s)
Arginine Vasopressin/metabolism , Brain/metabolism , Peptide Fragments/metabolism , Animals , Autoradiography , Binding Sites , Male , Rats , Rats, Inbred Strains , Tissue Distribution
15.
Life Sci ; 34(10): 977-84, 1984 Mar 05.
Article in English | MEDLINE | ID: mdl-6608041

ABSTRACT

Ac-[Nle4, D-Phe7]-alpha-MSH4-11-NH2 an octapeptide, is a melanotropin analogue (Ac-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-NH2), which is a superpotent agonist of frog and lizard skin melanocytes and mouse S 91 (Cloudman) melanoma cells. This melanotropin possesses ultraprolonged activity on melanocytes, both in vitro and in vivo, and the peptide is resistant to inactivation by serum enzymes. The tritium-labeled congener was prepared by direct incorporation of [3H]-labeled norleucine into the peptide. The melanotropic activity of the labeled peptide is identical to the unlabeled analogue. This labeled peptide should be useful for studies on the localization and characterization of melanotropin receptors.


Subject(s)
Melanocyte-Stimulating Hormones/analogs & derivatives , alpha-MSH/analogs & derivatives , Animals , Biological Assay , Dose-Response Relationship, Drug , Humans , Lizards , Melanocyte-Stimulating Hormones/chemical synthesis , Melanocyte-Stimulating Hormones/pharmacology , Melanocytes/drug effects , Rana pipiens , Rats , Rats, Inbred Strains , Skin/drug effects , Xenopus laevis
16.
Article in English | MEDLINE | ID: mdl-6141616

ABSTRACT

In an attempt to delineate the mechanism subserving the demonstrated central effects of the tripeptide, L-prolyl-L-leucyl-glycinamide (PLG) in mammals including humans, we developed a radioligand binding assay to characterize the binding of 3H-PLG to rat brain membranes. Equilibrium binding studies indicated that PLG binds to rat striatum with high affinity (KD = 4.69 +/- 0.50 nM), saturability (Bmax = 9.20 +/- 0.30 fmoles mg-1 protein) and reversibility. Kinetic data yielded a KD = 1.42 +/- 0.21 nM for rat striatum. Regional distribution profile of specific 3H-PLG binding revealed that the striatum has the highest density of PLG binding sites, followed by the hypothalamus and the cerebral cortex. Analogues of PLG compete for specific PLG binding in rat striatum with potencies parallelling their in vivo activities in behavioural systems. Our results support the existence of a unique class of putative peptide receptor sites specific for PLG mediating a spectrum of pharmacological effects.


Subject(s)
Brain/drug effects , MSH Release-Inhibiting Hormone/pharmacology , Receptors, Neurotransmitter/drug effects , Animals , Corpus Striatum/drug effects , Dose-Response Relationship, Drug , Kinetics , Male , Radioligand Assay , Rats , Rats, Inbred Strains , Structure-Activity Relationship , Synaptic Membranes/drug effects
17.
J Med Chem ; 22(7): 774-7, 1979 Jul.
Article in English | MEDLINE | ID: mdl-376847

ABSTRACT

Sixteen analogues of the luteinizing hormone-releasing hormone (LH-RH) were synthesized by the solid-phase method. In new and surprising relationships, it was found that the substitution of D-Trp into position 3 of [D- less than Glu1,D-Phe2,amino acid3,D-Phe6]-LH-RH significantly enhanced the antiovulatory potency, but substitution by Pro, N-Me-Phe,N-Me-Leu, or L-Trp reduced antiovulatory activity. The substitution of L- less than Glu in position 1 of [D-Phe2,Pro3,D-Phe6]-LH-RH by cyclohexylcarbonyl (Chc), benzoyl (Bz), Ac, Hyp, Ac-Met, hydrogen, Pro, and D- less than Glu residues, and the substitution of D-Phe in position 2 by D-Trp, D-His, D-Phg, and L-Phe residues resulted in analogues with no antiovulatory activity at 750 microgram/rat. Structural requirements for the design of inhibitors of higher potency have been discussed.


Subject(s)
Gonadotropin-Releasing Hormone/analogs & derivatives , Ovulation/drug effects , Amino Acid Sequence , Animals , Female , Gonadotropin-Releasing Hormone/chemical synthesis , Gonadotropin-Releasing Hormone/metabolism , Gonadotropin-Releasing Hormone/pharmacology , In Vitro Techniques , Pituitary Gland/drug effects , Pituitary Gland/metabolism , Rats , Structure-Activity Relationship
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