The effects of congenital brain serotonin deficiency on responses to chronic fluoxetine

The importance of reversing brain serotonin (5-HT) deficiency and promoting hippocampal neurogenesis in the mechanisms of action for antidepressants remain highly controversial. Here we examined the behavioral, neurochemical and neurogenic effects of chronic fluoxetine (FLX) in a mouse model of congenital 5-HT deficiency, the tryptophan hydroxylase 2 (R439H) knock-in (Tph2KI) mouse. Our results demonstrate that congenital 5-HT deficiency prevents a subset of the signature molecular, cellular and behavioral effects of FLX, despite the fact that FLX restores the 5-HT levels of Tph2KI mice to essentially the levels observed in wild-type mice at baseline. These results suggest that inducing supra-physiological levels of 5-HT, not merely reversing 5-HT deficiency, is required for many of the antidepressant-like effects of FLX. We also demonstrate that co-administration of the 5-HT precursor, 5-hydroxytryptophan (5-HTP), along with FLX rescues the novelty suppressed feeding (NSF) anxiolytic-like effect of FLX in Tph2KI mice, despite still failing to induce neurogenesis. Thus, our results indicate that brain 5-HT deficiency reduces the efficacy of FLX and that supplementation with 5-HTP can restore some antidepressant-like responses in the context of 5-HT deficiency. Our findings also suggest that feeding latency reductions in the NSF induced by chronic 5-HT elevation are not mediated by drug-induced increments in neurogenesis in 5-HT-deficient animals. Overall, these findings shed new light on the impact of 5-HT deficiency on responses to FLX and may have important implications for treatment selection in depression and anxiety disorders.     

Tamoxifen enhances the control of acromegaly treated with somatostatin analog lanreotide

We present the case of a 51-year old female patient with acromegaly that was resistant to somatostatin analogs and dopamine agonists. The patient was diagnosed with breast cancer requiring treatment with the anti-estrogen tamoxifen. Prior to initiating the treatment with tamoxifen, the IGF-I level was very high at 415% of the upper limit of normal for the patient’s age and sex. During the tamoxifen treatment, the level of IGF-I dropped spectacularly down to normal levels. This observation highlights the effect of an anti-estrogen treatment in certain female patients with acromegaly.     

Glucose status in patients with acromegaly receiving primary treatment with the somatostatin analog lanreotide

To describe glucose status changes in patients with acromegaly receiving somatostatin analog lanreotide as primary treatment. This retrospective, single-center study conducted during 1996-2008, included acromegalic patients receiving primary lanreotide treatment. Baseline and last follow-up visit assessments included glucose status (according to American Diabetes Association criteria), growth hormone (GH), and insulin-like growth factor-1 (IGF-1) levels. Glucose control was considered improved when fasting plasma glucose or antidiabetic treatments were reduced, and deteriorated if fasting glucose was the same/higher but with increased antidiabetic treatments. 42 patients (median age 50?years; range 29-75?years) were included. At baseline, 26 (62%) were normoglycemic, eight (19%) had impaired glucose tolerance/fasting glycemia, and eight (19%) had diabetes mellitus; family history of diabetes mellitus was significantly associated with abnormal glucose status. At final visit, the mean (SE) lanreotide dose was 108 (21) mg/month. Median treatment duration was 23?months, range 3-138?months, and 74% of patients received the 120-mg dose. Median GH levels decreased significantly (baseline, 12 [5-20] μg/l; final visit, 2.1 [1.0-4.7] μg/l; P?相似文献