TY - JOUR
T1 - Differential expression of LHRH-receptor in bovine nasal tissue and its role in deslorelin delivery
AU - Sundaram, Sneha
AU - Roy, Shyamal K.
AU - Kompella, Uday B.
N1 - Funding Information:
This work was supported by NIH grants DK064172 and EY013842. Sneha Sundaram was supported by UNMC Bukey Fellowship and the Pre-doctoral Fellowship from the American Heart Association. We are very thankful to Jean Deupree (Professor of the Department of Pharmacology, University of Nebraska Medical Center), for her assistance with the receptor binding assays and data analysis. We are very thankful to Dhirendra Singh (Professor of the Department of Ophthalmology, University of Nebraska Medical Center), and Nigar Fatma (Instructor of the Department of Opthalmology, University of Nebraska Medical Center), for their assistance with the Western blot analysis.
PY - 2009/2
Y1 - 2009/2
N2 - Deslorelin, a luteinizing hormone releasing hormone (LHRH) agonist, is transported via the LHRH-receptor (LHRH-R) and exhibits regional variation as follows: inferior turbinate posterior (ITP) > medium turbinate posterior (MTP) > medium turbinate anterior (MTA) of the bovine nasal mucosa. Differential LHRH-R expression in various regions of the nose is a potential explanation for regional variation in deslorelin transport. Thus, the objective was to determine whether LHRH-R expression exhibits regional variation in bovine nasal mucosa. LHRH-R density (Bmax) and affinity constant (Kd) were determined by saturation experiments using 0.5 mg tissue in the presence of increasing amounts of I125-deslorelin (100-100,000 cpm) at 4 °C for 4 h. The 50% inhibitory concentration (IC50) was determined by competition experiments using various amounts of unlabelled deslorelin (0.01-3000 ng) at 4 °C for 4 h. LHRH-R mRNA and protein expressions were determined using real-time PCR and Western blot analysis, respectively. LHRH-R Bmax and Kd varied between the regions of excised bovine nasal mucosa: ITP > MTP > MTA. The inhibition experiments yielded two IC50 concentrations which exhibited trends similar to Bmax and Kd. Real-time PCR and Western blot analysis indicated that LHRH-R expression exhibits similar trends: ITP > MTP > MTA. We identified two deslorelin binding sites in the nasal tissues, with high affinity sites representing approximately 60-70% of the total sites available. In summary, regional differences in nasal deslorelin transport correlate with regional differences in LHRH-R expression, with LHRH-R expression, peptide binding, and transport being the highest in the inferior turbinate posterior region of the nose.
AB - Deslorelin, a luteinizing hormone releasing hormone (LHRH) agonist, is transported via the LHRH-receptor (LHRH-R) and exhibits regional variation as follows: inferior turbinate posterior (ITP) > medium turbinate posterior (MTP) > medium turbinate anterior (MTA) of the bovine nasal mucosa. Differential LHRH-R expression in various regions of the nose is a potential explanation for regional variation in deslorelin transport. Thus, the objective was to determine whether LHRH-R expression exhibits regional variation in bovine nasal mucosa. LHRH-R density (Bmax) and affinity constant (Kd) were determined by saturation experiments using 0.5 mg tissue in the presence of increasing amounts of I125-deslorelin (100-100,000 cpm) at 4 °C for 4 h. The 50% inhibitory concentration (IC50) was determined by competition experiments using various amounts of unlabelled deslorelin (0.01-3000 ng) at 4 °C for 4 h. LHRH-R mRNA and protein expressions were determined using real-time PCR and Western blot analysis, respectively. LHRH-R Bmax and Kd varied between the regions of excised bovine nasal mucosa: ITP > MTP > MTA. The inhibition experiments yielded two IC50 concentrations which exhibited trends similar to Bmax and Kd. Real-time PCR and Western blot analysis indicated that LHRH-R expression exhibits similar trends: ITP > MTP > MTA. We identified two deslorelin binding sites in the nasal tissues, with high affinity sites representing approximately 60-70% of the total sites available. In summary, regional differences in nasal deslorelin transport correlate with regional differences in LHRH-R expression, with LHRH-R expression, peptide binding, and transport being the highest in the inferior turbinate posterior region of the nose.
KW - Deslorelin
KW - LHRH-receptor (LHRH-R)
KW - Luteinizing hormone releasing hormone (LHRH)
KW - Nasal turbinates
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U2 - 10.1016/j.peptides.2008.10.005
DO - 10.1016/j.peptides.2008.10.005
M3 - Article
C2 - 18992782
AN - SCOPUS:58149479558
VL - 30
SP - 351
EP - 358
JO - Peptides
JF - Peptides
SN - 0196-9781
IS - 2
ER -