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Biomedical subjects

Th B Twickler

Publications and source records attributed to Th B Twickler.

7 recordsLinked to original sources
PubMed2005

Improvement in insulin sensitivity without concomitant changes in body composition and cardiovascular risk markers following fixed administration of a very low growth hormone (GH) dose in adults with severe GH deficiency.

OBJECTIVE: Untreated GH-deficient adults are predisposed to insulin resistance and excess cardiovascular mortality. We showed previously that short-term treatment with a very low GH dose (LGH) enhanced insulin sensitivity in young healthy adults. The present study was therefore designed to explore the hypothesis that LGH, in contrast to the standard GH dose titrated to normalize serum IGF-I levels (SGH), may have differing effects on insulin sensitivity, body composition, and cardiovascular risk markers [lipid profile, C-reactive protein (CRP), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and adiponectin] in adults with severe GH deficiency. PATIENTS AND METHODS: In this 12-month open, prospective study, 25 GH-deficient adults were randomized to receive either a fixed LGH (0.10 mg/day, n = 13) or SGH (mean dose 0.48 mg/day, n = 12), and eight age- and body mass index (BMI)-matched GH-deficient adults acted as untreated controls. Fasting blood samples were collected at baseline and at months 1, 3, 6, 9 and 12. Assessments of insulin sensitivity, using the hyperinsulinaemic euglycaemic clamp technique, and body composition, using dual-energy X-ray absorptiometry, were performed at baseline and at month 12. RESULTS: The LGH decreased fasting glucose levels (P < 0.01) and enhanced insulin sensitivity (P < 0.02), but body composition, nonesterified fatty acid (NEFA) levels and cardiovascular risk markers were unchanged. The SGH did not modify insulin sensitivity, decreased truncal fat mass (P < 0.05), CRP (P < 0.05) and IL-6 (P < 0.05) levels, and increased NEFA levels (P < 0.05). No changes were observed with the untreated controls. CONCLUSION: Our data indicate that, in contrast to the SGH, fixed administration of the LGH enhances insulin sensitivity with no apparent effects on body composition, lipolysis and other surrogate cardiovascular risk markers in adults with severe GH deficiency. Thus, the LGH may potentially be a beneficial replacement dose in reducing type 2 diabetes risk in adults with severe GH deficiency.

Adult↗
PubMed2004

Effects of growth hormone deficiency and recombinant growth hormone therapy on postprandial gallbladder motility and cholecystokinin release.

In addition to cholecystokinin, other hormones have been suggested to be involved in regulation of postprandial gallbladder contraction. We aimed to evaluate effects of growth hormone (GH) on gallbladder contractility and cholecystokinin release. Gallbladder and gastric emptying (by ultrasound) and cholecystokinin release were determined before and after 6 months of recombinant human GH (rhGH) therapy in 12 patients with GH deficiency, after either a mixed (n = 5) or a liquid (n = 7) meal. Basal postprandial gallbladder contraction was severely impaired (19 +/- 2 and 26 +/- 3% of fasting volume after mixed and liquid meal, respectively). Histology and cholecystokinin sulfation patterns in duodenal biopsies from two patients were normal. After 6 months of rhGH therapy, fasting gallbladder volumes increased (from 20.8 +/- 0.9 to 25.9 +/- 1.1 mL, P < 0.05) and postprandial gallbladder emptying was restored (70 +/- 6 and 70 +/- 7% of fasting volume after mixed and liquid meal, respectively), without change of gastric emptying. Cholecystokinin secretion after a mixed meal and gallbladder sensitivity to cholecystokinin were significantly enhanced during rhGH replacement compared to the basal state. Postprandial cholecystokinin release, gallbladder responsiveness to cholecystokinin, and gallbladder emptying are severely impaired in the absence of GH. Reversibility during GH suppletion suggests its involvement in regulation of gallbladder contractility.

Adolescent↗
PubMed2004

Acromegaly and heart failure: revisions of the growth hormone/insulin-like growth factor axis and its relation to the cardiovascular system.

Cardiomyopathy is a major cause of death in overt acromegaly. Recent progress in research has increasingly revealed the molecular mechanisms concerning growth hormone and insulin-like growth factor in the development of heart failure. In this article, we propose mechanisms according to which heart failure occurs, and we aim to extrapolate this knowledge to more general processes involved in heart failure.

Acromegaly↗
PubMed2004

Insulin-like growth factors and pancreas beta cells.

Abstract Insulin-like growth factors (IGFs) have been implicated in normal growth, and especially foetal pancreas beta-cell development. As low birth weight has been implicated in the development of obesity and type 2 diabetes, much research has evolved into the importance of IGF and their signalling pathways for pancreas beta-cell development, and for type 2 diabetes. Insulin-like growth factor-I signalling has a lot in common with insulin signalling, and is involved in diverse cellular effects such as antiapoptosis, protein synthesis, cell growth and mitogenesis. Insulin-like growth factor-II can be bound by the insulin receptor A subtype and the IGF-1 receptor, which may explain its antiapoptotic effect. Various knock-out model studies indicate that absence of IGF-I or the IGF-1 receptor is critical for foetal and postnatal growth. Similarly, knock-out models of post-receptor molecules (such as IRS-2) point to the physiological role of IGFs for pancreas beta-cell development. A beta-cell-specific IGF-1 receptor knock out model indicates the importance of IGF-I for beta-cell function. The Goto-Kakizaki (GK) rat, a model for diabetes, has insufficient beta-cell development, which may be related to its defective IGF-II synthesis. As normal pancreas beta cells adapt to the prevailing insulin resistance with increasing beta-cell function, it is possible that insulin resistance interacts with IGF signalling in pancreas beta cells.

Animals↗