TAQ1 restriction fragment length polymorphism for pig growth hormone in pigs.

in Proceedings of the 14th IVPS Congress (1996, July)

Dissociation of increases in plasma insulin-like growth factor I and testosterone during the onset of puberty in bulls

in Journal of Reproduction and Fertility (1996), 106(1), 79-86

The present study was conducted to examine the relationship between plasma concentrations of testosterone, insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) during puberty, in male ... [more ▼]

The present study was conducted to examine the relationship between plasma concentrations of testosterone, insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) during puberty, in male calves treated with GnRH or testosterone propionate. Twelve male Holstein calves (10 weeks old) were assigned to the control group (n = 6), the GnRH-treated group (n = 3) or the testosterone-treated group (n = 3). For 8 weeks, the GnRH-treated group received a single i.v. injection of GnRH (0.5 mu g kg(-1) body mass) each day while the testosterone-treated group received an i.m. injection of testosterone propionate (0.5 mg kg(-1) body mass) twice a day. The calves were studied until they were 200 days old. Hormone treatments were stopped one month after puberty was reached in the control group. Blood samples were collected every 30 min for 8 h every third day. Hormone concentrations were determined by radioimmunoassay. Western ligand blotting and immunoblotting, using monoclonal antibodies against IGFBP-2, and IGFBP-3, were used to characterize the IGF-binding proteins. In the control group, puberty occurred at about 120 days of age and was associated with an increase in concentrations of testosterone, IGF-I and IGFBP-3 and a decrease in concentration of IGFBP-2. In the GnRH-treated group, plasma testosterone remained low until 8 weeks after establishment of puberty in the control group (4 weeks after the end of treatment). In the testosterone-treated group, testosterone was high during the treatment period and then decreased to prepubertal values when treatment was stopped. Testosterone values increased again to reach postpubertal values 5 weeks after the end of hormone treatment. Nevertheless, independent of testosterone status, the profile of IGF-I and the IGFBPs in the GnRH- and testosterone-treated groups were parallel to that reported for the control group with the transition from prepubertal to adult values at about 120 days of age. In conclusion, concentrations of testosterone, IGF-I and IGFBP-3 increase together, but probably independently, during the onset of puberty in male calves. [less ▲]

Maîtrise du développement foetal chez les bovins

Report (1996)

Alteration of the endocrinological status of growing calves by a glucocorticoids treatment

in Journal of Animal Science (1996), 74(suppl 1), 230

Evaluation of insuline-like growth horme-I (IGF-I) and their binding proteins (IGFBPs) in pigs

in Archivio Veterinario Italiano (1996), 46

Alteration of the endocrinological status of growing calves by a glucocorticoid treatment.

Poster (1996)

Pit-1 polymorphism and milk production parameters in Italian Holstein-Friesian bulls.

Poster (1996)

Alteration of the endocrinological status of growing calves by a glucocorticoid treatment.

in Journal of Animal Science (1996), 74(1), 230

Taqi Growth Hormone Gene Polymorphism And Milk Production Traits In Holstein-Friesian Cattle

in Animal Science (1996), 63

Characterization of growth hormone-binding protein in cattle plasma: prolactin-binding activity and 24-hour profile.

in Domestic Animal Endocrinology (1996), 13(1), 47-57

The purpose of this study was to characterize circulating growth hormone-binding proteins (GHBP) and prolactin-binding proteins (PRLBP) in cattle blood plasma. In particular, the 24-hr profile of these ... [more ▼]

The purpose of this study was to characterize circulating growth hormone-binding proteins (GHBP) and prolactin-binding proteins (PRLBP) in cattle blood plasma. In particular, the 24-hr profile of these molecules was investigated. The preincubation of bull plasma with iodinated bovine growth hormone (bGH) or bovine prolactin (bPRL), followed by gel filtration chromatography (Superdex 200; 1.6 x 60 cm column), resulted in the formation of essentially two complexes. The majority of [125I]bPRL eluted with the first one (M(r) approximately 600 kDa), whereas [125I]bGH mainly appeared in the second one (M(r) approximately 70 kDa). The fractions corresponding to these two peaks were analyzed by western ligand blotting (WLB), under reducing conditions. WLB revealed, respectively, 190-, 56-, 52-, and 28-kDa bands for the first peak and only 52- and 28-kDa bands for the second one. The nature of the 600-kDa peak is at present undetermined, but the 70-kDa one was previously identified as high-affinity GHBP. Displacement studies demonstrated that bGH and bPRL were both able to bind to this GHBP, because the bGH- and bPRL-binding activities of this protein could be saturated by an excess of either of these two hormones. This was indirectly confirmed by the close correlation (r = 0.615; P = 0.0001; n = 155) observed between plasma bGH- and bPRL-binding activities, because this correlation could suggest that both ligands are bound to the same proteins. The temporal concentrations of plasma GHBP were measured in samples collected at 20-min intervals for 24 hr from 8 young bulls. The evaluation of GHBP was realized by WLB, followed by densitometric analysis. Some fluctuations were observed, but these were not correlated with bGH release, even with a +/- 2-hr lag period. In summary, we found that bovine high-affinity GHBP binds not only bGH, but also bPRL. A second type of protein, of higher molecular weight, also binds these two hormones, but further investigations are needed to determine its nature. Finally, GHBP concentrations in cattle blood plasma apparently show fluctuations over a 24-hr period, but no correlation was found between these fluctuations and plasma growth hormone concentrations. [less ▲]