| 1. |
- Wallenius, Kristina, 1973, et al.
(author)
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Liver-derived IGF-I regulates GH secretion at the pituitary level in mice.
- 2001
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In: Endocrinology. - 0013-7227. ; 142:11, s. 4762-70
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Journal article (peer-reviewed)abstract
- We have reported that liver-specific deletion of IGF-I in mice (LI-IGF-I-/-) results in decreased circulating IGF-I and increased GH levels. In the present study, we determined how elimination of hepatic IGF-I modifies the hypothalamic-pituitary GH axis to enhance GH secretion. The pituitary mRNA levels of GH releasing factor (GHRF) receptor and GH secretagogue (GHS) receptor were increased in LI-IGF-I-/- mice, and in line with this, their GH response to ip injections of GHRF and GHS was increased. Expression of mRNA for pituitary somatostatin receptors, hypothalamic GHRF, somatostatin, and neuropeptide Y was not altered in LI-IGF-I-/- mice, whereas hypothalamic IGF-I expression was increased. Changes in hepatic expression of major urinary protein and the PRL receptor in male LI-IGF-I-/- mice indicated an altered GH release pattern most consistent with enhanced GH trough levels. Liver weight was enhanced in LI-IGF-I-/- mice of both genders. In conclusion, loss of liver-derived IGF-I enhances GH release by increasing expression of pituitary GHRF and GHS receptors. The enhanced GH release in turn affects several liver parameters, in line with the existence of a pituitary-liver axis.
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| 2. |
- Casselbrant, Anna, 1970, et al.
(author)
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Morphological Adaptation in the Jejunal Mucosa after Iso-Caloric High-Fat versus High-Carbohydrate Diets in Healthy Volunteers: Data from a Randomized Crossover Study
- 2022
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In: Nutrients. - : MDPI AG. - 2072-6643. ; 14:19
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Journal article (peer-reviewed)abstract
- Background and aims: The conditions for jejunal glucose absorption in healthy subjects have not been thoroughly studied. In this study we investigated differences in the jejunal villi enlargement factor, as well as ultrastructural aspects of the surface enterocytes and mitochondria, comparing 2 weeks of high-carbohydrate (HCD) versus high-fat diets (HFD). We also measured the ketogenesis rate-limiting enzyme 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) in relation to jejunal mitochondria. Methods: A single-centre, randomized, unblinded crossover study in 15 healthy volunteers ingesting strictly controlled equicaloric diets (either HCD or HFD), with 60% energy from the respective source. An enteroscopy was carried out after 2 weeks of each diet and jejunal mucosal biopsies were acquired. Conventional histology, immunofluorescent staining, transmission electron microscopy and confocal microscopy were used. Results: The villi did not demonstrate any change in the epithelial enlargement factor. Despite an increased mitosis, there were no changes in apoptotic indices. However, the ultrastructural analysis demonstrated a significant increase in the enlargement factor at the bases of the villi. The mitochondria demonstrated increased amounts of cristae after the HFD. The confocal microscopy revealed increased HMGCS2 per mitochondrial marker at the top of the villi after the HFD compared to the HCD. Conclusion: There is a morphometric adaption in the jejunal mucosa following the 2-week diets, not only on a histological level, but rather on the ultrastructural level. This study supports the notion that mitochondrial HMGCS2 is regulated by the fat content of the diet and is involved in the expression of monosaccharide transporters.
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| 3. |
- Hernandez-Carretero, A., et al.
(author)
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Obesity-induced changes in lipid mediators persist after weight loss
- 2018
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In: International Journal of Obesity. - : Springer Science and Business Media LLC. - 0307-0565 .- 1476-5497. ; 42:4, s. 728-736
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Journal article (peer-reviewed)abstract
- Background:Obesity induces significant changes in lipid mediators, however, the extent to which these changes persist after weight loss has not been investigated.Subjects/Methods:We fed C57BL6 mice a high-fat diet to generate obesity and then switched the diet to a lower-fat diet to induce weight loss. We performed a comprehensive metabolic profiling of lipid mediators including oxylipins, endocannabinoids, sphingosines and ceramides in key metabolic tissues (including adipose, liver, muscle and hypothalamus) and plasma.Results:We found that changes induced by obesity were largely reversible in most metabolic tissues but the adipose tissue retained a persistent obese metabolic signature. Prostaglandin signaling was perturbed in the obese state and lasting increases in PGD 2, and downstream metabolites 15-deoxy PGJ 2 and delta-12-PGJ 2 were observed after weight loss. Furthermore expression of the enzyme responsible for PGD 2 synthesis (hematopoietic prostaglandin D synthase, HPGDS) was increased in obese adipose tissues and remained high after weight loss. We found that inhibition of HPGDS over the course of 5 days resulted in decreased food intake in mice. Increased HPGDS expression was also observed in human adipose tissues obtained from obese compared with lean individuals. We then measured circulating levels of PGD 2 in obese patients before and after weight loss and found that while elevated relative to lean subjects, levels of this metabolite did not decrease after significant weight loss.Conclusions:These results suggest that lasting changes in lipid mediators induced by obesity, still present after weight loss, may play a role in the biological drive to regain weight. © 2018 Macmillan Publishers Limited.
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| 4. |
- van Santen, Selveta S, et al.
(author)
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Bariatric Surgery for Hypothalamic Obesity in Craniopharyngioma Patients: A Retrospective, Matched Case-Control Study.
- 2021
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 106:11
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Journal article (peer-reviewed)abstract
- Craniopharyngioma is a sellar tumor associated with high rates of pituitary deficiencies (~98%) and hypothalamic obesity (~50%).To determine the efficacy regarding long-term weight loss after bariatric surgery in obese craniopharyngioma patients with hypothalamic dysfunction.Retrospective case control study.Multicenter international study.Obese craniopharyngioma patients (N = 16; of which 12 women) with a history of bariatric surgery [12 Roux-en-Y gastric bypass, 4 sleeve gastrectomy; median age of 21 years (range 15-52), median follow-up 5.2 years (range 2.0-11.3)] and age/sex/surgery/BMI-matched obese controls (N = 155).Weight loss and obesity-related comorbidities up to 5 years after bariatric surgery were compared and changes in hormonal replacement therapy evaluated.Mean weight loss at 5-year follow-up was 22.0% (95% CI 16.1, 27.8) in patients versus 29.5% (28.0, 30.9) in controls (P = 0.02), which was less after Roux-en-Y gastric bypass (22.7% [16.9, 28.5] vs. 32.0% [30.4, 33.6]; P = 0.003) but at a similar level after sleeve gastrectomy (21.7% [-1.8, 45.2] vs. 21.8% [18.2, 25.5]; P = 0.96). No major changes in endocrine replacement therapy were observed after surgery. One patient died (unknown cause). One patient had long-term absorptive problems.Obese patients with craniopharyngioma had a substantial mean weight loss of 22% at 5-year follow-up after bariatric surgery, independent of type of bariatric surgery procedure. Weight loss was lower than in obese controls after Roux-en-Y gastric bypass. Bariatric surgery appears effective and relatively safe in the treatment of obese craniopharyngioma patients.
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