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R M Schimpff

Publications and source records attributed to R M Schimpff.

79 records · Page 5Linked to original sources
PubMedDate not supplied

Possible role of plasma neurotensin on growth hormone regulation in neonates.

OBJECTIVE: To evaluate secretion of plasma neurotensin (NT) which could be involved as a peripheral signal in growth hormone (GH) regulation, NT release was measured during early postnatal life, a period of striking changes in GH secretion. METHODS: Blood samples were collected from 19 normal full-term neonates on day 5 and at 3 months of age to evaluate plasma NT concentrations by radioimmunoassay, serum growth hormone (GH) levels using an immunofluorometric assay, and serum insulin-like growth factor-I (IGF-I) values by radioimmunoassay. RESULTS: Five day-old neonates showed significantly higher (p < 0.001) mean (+/- SEM) plasma NT levels (83.55 +/- 12.07 fmol/ml) compared with those in 11 prepubertal children and those in 14 adults who were studied as control subjects (13.30 +/- 2.90 and 9.70 +/- 1.10 fmol/ml, respectively). In 5 day-old neonates we observed significantly higher (p < 0.001) serum GH levels (29.53 +/- 3.40 ng/ml) compared with those in the prepubertal children (1.26 +/- 0.28 ng/ml). Five day-old neonates showed significantly lower (p < 0.001) serum IGF-I concentrations (27.01 +/- 0.77 ng/ml) than those in the prepubertal children (210 +/- 25 ng/ml). At 3 months of age, plasma NT levels (59.37 +/- 7.47 fmol/ml) and serum GH values (4.40 +/- 0.60 ng/ml) were significantly decreased (p < 0.001). At the 3rd month of life, serum IGF-I levels (44.88 +/- 4.30 ng/ml) were increased significantly (p < 0.001). CONCLUSIONS: The human neonate showed very high concentrations of NT and GH in comparison with those observed in control subjects. The postnatal rise in IGF-I values is presumed to determine the fall in serum GH concentrations by stimulating somatostatin secretion. Neurotensin could be involved as a peripheral signal in the inhibitory mechanisms mediated by release of somatostatin.

Adult↗
PubMedDate not supplied

Plasma neurotensin levels in prepubertal children and adults: possible involvement in the regulation of growth hormone secretion.

The present study investigated a possible relationship between plasma neurotensin (NT) and serum growth hormone (GH) levels after GH-stimulation provocative tests in humans. Samples were obtained from twelve prepubertal children and sixteen normal adult volunteers. Basal plasma NT levels were higher in children with growth delay (19.02 +/- 4.01 fmol/ml) (mean +/- SEM) than in normal adults (6.13 +/- 1.1 fmol/ml) (p < 0.001). Basal GH levels in children (1.52 +/- 0.06 ng/ml) were not different from those in adults (0.60 +/- 0.41 ng/ml). After stimulation of GH secretion, NT values decreased when GH peaked, and increased when GH levels diminished. These data suggest that plasma NT levels may be involved in the regulation of GH secretion, as a peripheral signal, probably through modulation of somatostatin release from the median eminence.

Adolescent↗
PubMedDate not supplied

[Relationships between growth, and plasma growth hormone and growth factors under normal physiological conditions and during pathological states (author's transl)].

Growth hormone (GH) and somatomedin (Sm) are the main factors of human growth. Sm is GH-dependent, but Sm increase after hGH injection in hypopituitary dwarfs is slow, and preceded by a decrease. The liver and kidneys are the main places of Sm production in vivo, the liver having probably also a regulatory effect. In vitro, GH-dependent production of Sm may be obtained from fibroblasts as well as from liver cells. Sm activates thymidine uptake by cultured human fibroblasts and by activated human lymphocytes, this effect needing cofactors from serum. Discrepant correlations between growth, GH and Sm are found in some pathological situations, such as obesity, craniopharyngioma, celiac disease, infantile malnutrition. Moreover, transferrin, a plasma protein, correlates also with growth.

Dwarfism↗