The endocrinology of aging

Most aging individuals die from atherosclerosis, cancer, or dementia; but in the oldest old, loss of muscle strength resulting in frailty is the limiting factor for an individual's chances of living an independent life until death. Three hormonal systems show decreasing circulating hormone concentrations during normal aging: (i) estrogen (in menopause) and testosterone (in andropause), (ii) dehydroepiandrosterone and its sulphate (in adrenopause), and (iii) the growth hormone/insulin-like growth factor I axis (in somatopause). Physical changes during aging have been considered physiologic, but there is evidence that some of these changes are related to this decline in hormonal activity. Hormone replacement strategies have been developed, but many of their aspects remain controversial, and increasing blood hormone levels in aging individuals to those found during mid-adult life has not been uniformly proven to be safe and of benefit.</jats:p

Pregnancy and acromegaly

Introduction: Acromegaly is a rare disorder in which, due to the high incidence of secondary hypogonadism, pregnancies are relatively rare. However, some women with acromegaly do get pregnant, which brings along questions about medication, complications and follow-up. This review tries to address these issues and provide the reader with practical information. Methods: This review summarizes published data. Conclusions: Acromegaly is a disorder that is characterized by changes in growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin concentrations and actions. All these hormones are important in pregnancy as well. In principle, the fetal-placental collaboration between mother and child more-or-less takes over the control over GH and IGF-1, not only in normal physiology but also to a certain extend in acromegaly. When medication for the high GH levels or actions is continued during pregnancy, both dopamine agonists, somatostatin analogs and GH receptor antagonists have been used and the available data suggest that there are no adverse consequences on mother or fetus to date. However, it is strongly advised to stop any medical intervention during pregnancy until more data are available on the safety of these compounds. Also, medical treatment is not needed as tumor size and disease activity are not reported to escape

Extrapancreatic insulin effect of glibenclamide

In eight patients with uncomplicated non insulin dependent diabetes mellitus, serum insulin levels, serum C-peptide levels and blood glucose levels were measured before and after oral administration of glibenclamide 0.1 mg/kg body weight and a test meal, or after a test meal alone. The rise in serum insulin levels persisted longer after glibenclamide. The initial rise in serum insulin was of the same magnitude in both situations, as was the rise in serum C-peptide levels during the entire 5 h study. It is concluded that glibenclamide is able to maintain a more protonged increase in serum insulin levels by inhibiting the degradation of insulin in the vascular endothelial cells of the liver. The inhibition contributes to the blood glucose lowering effect of glibenclamide

Pituitary adenomas, some diagnostic and therapeutical aspects

The treatment of almost all types of pituitary adenomas has changed considerably in recent years. New types of drugs as well as improved application forms of older drug therapies are now becoming more and more available for everyday treatment of patients with these relatively rare diseases. For the most frequently occurring pituitary adenomas the drugs of first choice are described, as well as other available treatments, their indications and efficacies. Also the main side-effects are described

Combined treatment of somatostatin analogues with pegvisomant in acromegaly

Treatment of acromegaly with monotherapy long-acting somatostatin analogues (LA-SSA) as primary treatment or after neurosurgery can only achieve complete normalization of insulin-like growth factor I (IGF-I) in roughly 40 % of patients. Recently, one of the acromegaly consensus groups has recommended switching to combined treatment of LA-SSA and pegvisomant (PEGV) in patients with partial response to LA-SSAs. This combination of LA-SSA and PEGV, a growth hormone receptor antagonist, can normalize IGF-I levels in virtually all patients, requiring that the adequate dose of PEGV is used. The required PEGV dose varies significantly between individual acromegaly patients. One of the advantages of the combination therapy is that tumor size control or even tumor shrinkage can be observed in a vast majority of patients. The main side effects of the combination treatment are gastrointestinal symptoms, lipohypertrophy and transient elevated liver transaminases. In this review we provide an overview of the efficacy and safety of the combined treatment of LA-SSAs with PEGV

Acromegaly: the significance of serum total and free IGF-I and IGF-binding protein-3 in diagnosis

We have studied the physiological and clinical relevance of measurements of serum total and free IGF-I and IGF-binding protein-3 (IGFBP-3) in 57 previously untreated patients with active acromegaly (32 males, 25 females; mean age 47 years) as compared with sex- and age-matched normal healthy controls. Serum total and free IGF-I, but not IGFBP-3, are suitable biochemical parameters for screening for acromegaly. In acromegalics, the mean 24 h serum GH, total IGF-I and IGFBP-3 levels tend to decrease with age. However, in our series of patients, mean 24 h serum GH levels, IGFBP-3, total and free IGF-I do not correlate with disease activity in acromegaly

Octreotide

A peptide inhibiting the release of growth hormone was originally detected accidentally during studies of the distribution of growth hormone–releasing factor in the hypothalamus of rats. This peptide, called somatostatin, proved to be a cyclic peptide consisting of 14 amino acids. Subsequent work has considerably expanded this initially simple concept of somatostatin as a peptide whose main function is the regulation of growth hormone secretion. Today, somatostatin is best regarded as a phylogenetically ancient, multigene family of peptides with two important bioactive products: somatostatin-14 and somatostatin-28, the latter a congener of somatostatin-14 extended at the N-terminal