Regulation of growth hormone secretion in ruminants

Regulation of growth hormone (GH) in ruminants was studied by infusing exogenous GH-releasing factor (GHRF), somatostatin (SRIH), and GH intravenously into animals and monitoring the levels of plasma hormones. Exogenous GHRF increased GH secretion in a dose-dependent manner in sheep and cattle. Intravenous infusion of SRIH in cattle suppressed the GH response to injections of GHRF. Intravenous injections of GHRF six times per day in older sheep caused a conservation of urinary nitrogen. In a similar study with young calves, changes in nitrogen metabolism were not significant;Plasma hormone concentrations and body composition were measured in intact and castrated, male and female cattle at 5, 8, 12, and 15 mo of age. As the animals aged, plasma somatomedin-C (Sm-C), testosterone (T), and insulin (I) increased while GH half-life, GH secretion rate (SR)/kg body weight (bwt), GH baseline concentrations, number and amplitude of GH secretion periods, and GH response to exogenous GHRF declined. The rate of fat, protein, water, and ash deposition was different between 8 to 12 mo nd 12 to 15 mo of age. Bulls differed from steers, heifers and ovariectomized heifers by higher baseline concentrations of GH; increased periods of secretion of GH with greater amplitude; increased GH SR; higher concentrations of T, total estrogens, and Sm-C; and higher protein, water and ash and lower fat in empty body gain. Females in comparison with males had higher concentrations of thyroid hormones, lower GH concentrations and GH SR/kg bwt, fewer GH secretory periods with less amplitude, and greater percent body fat. Castrates had less total estrogens, T, and Sm-C with greater levels of triiodothyronine and thyroxine. Overall GH concentrations, GH SR/kg bwt and GH:I ratio in the blood were negatively associated with percent empty body fat and positively associated with percent empty body protein

Differential gene expression profile reveals deregulation of pregnancy specific β1 glycoprotein 9 early during colorectal carcinogenesis

BACKGROUND: APC (Adenomatous polyposis coli) plays an important role in the pathogenesis of both familial and sporadic colorectal cancer. Patients carrying germline APC mutations develop multiple colonic adenomas at younger age and higher frequency than non-carrier cases which indicates that silencing of one APC allele may be sufficient to initiate the transformation process. METHODS: To elucidate the biological dysregulation underlying adenoma formation we examined global gene expression profiles of adenomas and corresponding normal mucosa from an FAP patient. Differential expression of the most significant gene identified in this study was further validated by mRNA in situ hybridization, reverse transcriptase PCR and Northern blotting in different sets of adenomas, tumours and cancer cell lines. RESULTS: Eighty four genes were differentially expressed between all adenomas and corresponding normal mucosa, while only seven genes showed differential expression within the adenomas. The first group included pregnancy specific β-1 glycoprotein 9 (PSG9) (p < 0.006). PSG9 is a member of the carcinoembryonic antigen (CEA)/PSG family and is produced at high levels during pregnancy, mainly by syncytiotrophoblasts. Further analysis of sporadic and familial colorectal cancer confirmed that PSG9 is ectopically upregulated in vivo by cancer cells. In total, deregulation of PSG9 mRNA was detected in 78% (14/18) of FAP adenomas and 75% (45/60) of sporadic colorectal cancer cases tested. CONCLUSION: Detection of PSG9 expression in adenomas, and at higher levels in FAP cases, indicates that germline APC mutations and defects in Wnt signalling modulate PSG9 expression. Since PSG9 is not found in the non-pregnant adult except in association with cancer, and it appears to be an early molecular event associated with colorectal cancer monitoring of its expression may be useful as a biomarker for the early detection of this disease

Regulation of growth hormone secretion in ruminants

Regulation of growth hormone (GH) in ruminants was studied by infusing exogenous GH-releasing factor (GHRF), somatostatin (SRIH), and GH intravenously into animals and monitoring the levels of plasma hormones. Exogenous GHRF increased GH secretion in a dose-dependent manner in sheep and cattle. Intravenous infusion of SRIH in cattle suppressed the GH response to injections of GHRF. Intravenous injections of GHRF six times per day in older sheep caused a conservation of urinary nitrogen. In a similar study with young calves, changes in nitrogen metabolism were not significant;Plasma hormone concentrations and body composition were measured in intact and castrated, male and female cattle at 5, 8, 12, and 15 mo of age. As the animals aged, plasma somatomedin-C (Sm-C), testosterone (T), and insulin (I) increased while GH half-life, GH secretion rate (SR)/kg body weight (bwt), GH baseline concentrations, number and amplitude of GH secretion periods, and GH response to exogenous GHRF declined. The rate of fat, protein, water, and ash deposition was different between 8 to 12 mo nd 12 to 15 mo of age. Bulls differed from steers, heifers and ovariectomized heifers by higher baseline concentrations of GH; increased periods of secretion of GH with greater amplitude; increased GH SR; higher concentrations of T, total estrogens, and Sm-C; and higher protein, water and ash and lower fat in empty body gain. Females in comparison with males had higher concentrations of thyroid hormones, lower GH concentrations and GH SR/kg bwt, fewer GH secretory periods with less amplitude, and greater percent body fat. Castrates had less total estrogens, T, and Sm-C with greater levels of triiodothyronine and thyroxine. Overall GH concentrations, GH SR/kg bwt and GH:I ratio in the blood were negatively associated with percent empty body fat and positively associated with percent empty body protein.</p