Associations of the growth hormone receptor (GHR) gene polymorphisms with adiposity and IGF-I activity in adolescents.

OBJECTIVE: To explore the genetic effect of the GH receptor (GHR) on obesity and related metabolic parameters in Hong Kong Chinese adolescents. CONTEXT: Obesity is a growing global epidemic. Increasing evidence suggests that the GH-IGF-I axis plays an important role in regulating adiposity and insulin sensitivity. DESIGN: We examined the associations of genetic variants of GHR with serum IGF-I and IGFBP-3 levels as well as obesity-related metabolic traits in Hong Kong Chinese adolescents. PATIENTS: Nine hundred and eighty-one randomly selected Hong Kong Chinese adolescents from 14 schools. MEASUREMENTS: We genotyped 17 single nucleotide polymorphisms (SNP) at GHR and measured serum IGF-I and IGFBP-3 levels as well as obesity-related metabolic traits including fasting plasma glucose, insulin and lipid levels. RESULTS: There were significant associations between rs4410646 and the body composition (P = 0.0044) and blood pressure factor scores (P = 0.00017). Carriers of the CC genotype had lower body mass index, percentage body fat, waist and hip circumferences than AC and AA genotype carriers (P = 0.00030-0.0094). There was also association between rs7703713 and the IGF-I activity factor score (P = 0.0033). The GA and AA carriers of rs7703713 had higher serum IGF-I, higher serum IGFBP-3 and higher IGF-I/IGFBP-3 molar ratio (P = 0.00069-0.025). Haplotype analysis did not increase the significance of associations. CONCLUSION: Our results support the role of GHR gene polymorphisms in modulating adiposity and IGF-I activity in adolescents. Examination of interactions of these SNPs with lifestyle, environmental and perinatal factors may provide further insights into their long-term effects on obesity and metabolic risks.

Molecular coordinated regulation of gene expression during ovarian development in the penaeid shrimp.

To understand the molecular events of ovarian development in penaeid shrimp, RNA arbitrarily primed polymerase chain reaction (RAP-PCR) was used to identify differentially expressed genes during ovarian maturation in Metapenaeus ensis. From a screening of 700 clones in a cDNA library of the shrimp ovary by the products of RAP-PCR of different maturation stages, 91 fragments with differentially expressed pattern as revealed by dot-blot hybridization were isolated and sequenced. Forty-two of these fragments show significant sequence similarity to known gene products and the differentially expressed pattern of 10 putative genes were further characterized via Northern hybridization. Putative glyceraldehyde-3-phosphate dehydrogenase and arginine kinase are related to provision of energy for active cellular function in oocyte development. Translationally controlled tumor protein, actin, and keratin are related to the organization of cytoskeleton to accomplish growth and development of oocytes. High mobility group protein DSP1, heat shock protein 70, and nucleoside diphosphate kinase may act as repressors before the onset of ovarian maturation. Peptidyl-prolyl cis-trans isomerase and glutathione peroxidase are related to the stabilization of proteins and oocytes. This study provides new insights on the molecular events in the ovarian development in the shrimp.