| 1. |
- Elimam, A, et al.
(författare)
-
Growth hormone treatment downregulates serum leptin levels in children independent of changes in body mass index
- 1999
-
Ingår i: Hormone research. - : S. Karger AG. - 0301-0163. ; 52:2, s. 66-72
-
Tidskriftsartikel (refereegranskat)abstract
- The changes in serum leptin levels during growth hormone (GH) treatment were studied in 27 children, 17 with GH deficiency (GHD), 10 with idiopathic short stature (ISS), and 9 with Prader-Willi syndrome (PWS). Within 1 month of GH treatment, serum leptin levels decreased by 40% in the GHD children (p < 0.01). There was no significant change in serum leptin level in the children with ISS. In children with PWS, the mean serum leptin level decreased by almost 60% after 3 months of treatment (p < 0.001). Thereafter, no further decline was observed in any of the 3 groups. Changes in body composition became evident first after the 3 months of treatment. In the GHD children, the BMI was unchanged while the mean body fat percentage was 2.7% lower after 1 year of GH treatment (p < 0.05). In the ISS children, neither BMI nor body fat percentage were significantly changed during treatment. The PWS children exhibited a significant decrease in BMI after 6 months of GH treatment without any further change during the remaining period of treatment. In this group, the mean body fat percentage decreased from 42 ± 2.4 to 28 ± 2.2% after treatment (p < 0.001). The finding that the fall in leptin occurs before changes in body composition become detectable suggests a direct effect of GH on leptin production, metabolism, or clearance.
|
|
| 2. |
- Elimam, A, et al.
(författare)
-
In vitro effects of leptin on human adipocyte metabolism
- 2002
-
Ingår i: Hormone research. - : S. Karger AG. - 0301-0163. ; 58:2, s. 88-93
-
Tidskriftsartikel (refereegranskat)abstract
- <i>Objective:</i> Leptin receptors are expressed in adipocytes, suggesting potential autocrine/paracrine effects. Studies on the direct effects of leptin on adipose tissue metabolism in different species have yielded controversial data. To assess the in vitro effects of leptin on human adipocyte metabolism: lipolysis, the insulin-induced inhibition of lipolysis and lipogenesis were studied in adipocytes obtained from infants and adults. <i>Methods:</i> Lipolysis was studied by incubating adipocytes with increasing concentrations of leptin or isoprenaline. Glycerol in the incubation medium was measured as an indicator of lipolysis. For the lipogenesis and insulin-induced inhibition of lipolysis experiments, the cells were preincubated with 0, 25, or 250 ng/ml of leptin for 2 h. <i>Results:</i> Leptin did not stimulate lipolysis in human adipocytes, either in children or adults. Preincubation with leptin did not affect the insulin-induced inhibition of lipolysis, but decreased the insulin-induced lipogenesis (p < 0.05). <i>Conclusions:</i> This study shows that leptin has no direct lipolytic effect in human adipocytes. The lack of effect on the insulin-induced inhibition of lipolysis and the negative effect on lipogenesis indicates that the effect of leptin is not at the proximal insulin-signalling pathway but further downstream.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Elimam, A, et al.
(författare)
-
Meal timing, fasting and glucocorticoids interplay in serum leptin concentrations and diurnal profile
- 2002
-
Ingår i: European journal of endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 147:2, s. 181-188
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In a previous study, we reported a 4-fold increase in serum leptin following total parenteral nutrition given after surgery. We hypothesised that the perioperative fasting and stress contributed to this, possibly mediated by increased serum insulin and cortisol. OBJECTIVE: To test the hypothesis that fasting, in combination with glucocorticoids, sensitises the leptin response to subsequent energy intake. DESIGN: Healthy volunteers were randomised into two groups, one group received dexamethasone (DEX), 0.1 mg twice daily for 3 days, while the other group served as a control. Each group was then subdivided into two feeding protocols. Protocol 1, where a standard meal was given at 0, 24, 36 and 48 h and protocol 2 where the same meal was given at 0 and 48 h. Blood samples were drawn before, as well as every other hour during the study period for determination of serum leptin, insulin, glucose and cortisol concentrations. RESULTS: In all groups serum leptin increased significantly following each meal (P<0.01). The rise in serum leptin in response to the standard meal was higher when the meal was taken in the evening (P<0.001) or following longer duration of fasting (P<0.02). In those fasting for 48 h, leptin decreased by 60% and showed no diurnal variation. DEX intake increased leptin concentrations in those fasting for short periods (P<0.02) but not for 48 h. CONCLUSIONS: Long durations of fasting sensitise the response of leptin to subsequent energy intake and abolish the DEX-induced upregulation of leptin. Meal timing is an important factor determining the leptin diurnal rhythm, but other factors must contribute since the leptin response to a standard meal taken in the evening was greater than to the same meal taken in the morning.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
