Glucose tolerance glucose utilization and insulin secretion in ageing

Muller*, Josephine M. Egan*, Reubin Andres*, Johannes Veldhuisf and Graydon S. Meneilly Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, *Laboratory of Clinical Physiology, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore 21224, MD, University of Virginia, Division of Endocrinology and Metabolism, Charlottesville, VA 22908, USA, and Department of Medicine, University of...

The incretin effect in ageing and in type 2 diabetes

Incretin is the umbrella term to cover the multiple gut factors (now known to be hormones) which augment insulin response above that which can be attributed to glucose alone. This insulinotropic effect has been demonstrated by matching the time course of the plasma glucose excursion following an OGTT with both an i.v. infusion of glucose (Perley & Kipnis 1967) and during a hyperglycaemic clamp. In the hyperglycaemic clamp, plasma glucose was increased to * 11 mmol l for 2 h on two different...

Testicular dysfunction

Reproductive ageing in the BN rat is characterized by low serum testosterone levels (Zirkin et al 1993, Wang et al 1993, 1999). Low serum testosterone levels are also a hallmark of the ageing male demonstrated in both cross-sectional and longitudinal studies (Vermeulen 1991, Gray et al 1991). We studied serum testosterone levels and sperm concentration in 6, 9, 12, 15, 18 and 31 month-old BN rats. Beginning at 15 months, plasma testosterone and inhibin levels both showed a progressive decline...

The concept of frailty and successful ageing

Age-related disability is characterized by generalized weakness, impaired mobility, impaired balance and poor endurance. This state is also called 'frailty' and is defined as a syndrome of multi-system reduction in physiological capacity as a result of which an older person's function may be severely compromised by minor environmental challenges, giving rise to the condition 'unstable disability' (Campbell & Buchner 1997). The increase in heterogeneity with age makes research findings more...

Clinical consequences of the decline in activity of the hormonal systems

Testosterone has long been known for its anabolic effects (Brodsky et al 1996). Muscle weakness, anaemia, lowered bone mass, and mood disturbances rapidly normalize in mid-adult hypogonadal men during T replacement therapy. Since the decrease in serum T concentrations occurs in parallel with the decrease in muscle mass, strength and bone mass, it has been suggested that these are causatively related. Several cross-sectional and longitudinal studies have demonstrated relationships in older men...

Fpg

Diabetic by FPG + GTT Diabetic by FPG Diabetics missed if no GTT FIG. 3. Distributions for diagnosis of diabetes (D) made from FPG (5 7.0 mmol l x-axis) and from two-hour plasma glucose level following OGTT (511.1 mmol l y-axis) in the BLSA population. We summarized 25 reports of studies that have computed the prevalence of diabetes in a population when both fasting glucose and the glucose tolerance test (GTT) were used (the WHO recommendation) in contrast to the prevalence when only the...

Allostasis allostatic load and ageing

Another shift in the neuroregulatory perspective is the proposal that ageing is related to lifetime stress, under the concepts of allostasis and allostatic load. Sterling & Eyer (1988) introduced the term allostasis to explain morbidity and mortality associated with chronic stress, especially social stress in human populations. They defined allostasis as 'maintaining stability through change'. The boundaries between allostasis and related constructs such as homeostasis, adaptation and...

The effect of insulin and IGF1 on the cytoskeleton in relation to SMC migration

The cytoskeleton is a complex network of protein filaments extending throughout the cytoplasm that is involved in a range of cell processes. Of the three main 10 min after insulin 10 imin after insulin + diltiazem FIG. 2. Insulin-induced F-actin reorganization near the membrane of human vascular smooth muscle cells showing a ruffling which does not appear when Ca2+ channels of these cells are blocked by diltiazem. The results are similar in the case of IGF1 (unpublished). 10 min after insulin...

Sexuality

Since antiquity, history and literature are replete with references to the waning of male virility, in all its ambiguities, with age. The seemingly inexhaustible repertoire of remedies to stave it off testifies to the ubiquity of this human fixation. In particular, the decline in male sexuality in old age, being both emblematic and problematic, it is not surprising that aphrodisiacs are among the most ancient and ubiquitous of folk remedies. The modern educated layman, however, having lost...

The ageing female reproductive axis II ovulatory changes with perimenopause

Division of Endocrinology and Metabolism, University of British Columbia, Vancouver Hospital andHealth Sciences Centre, Vancouver, BC, Canada V5Z 1C6 A bstract. Perimenopause, a complex physiological transition for midlife women, begins with changes in experiences many years before cycles become irregular, oestradiol levels decrease or follicle-stimulating hormone levels increase. Erratic and average higher oestradiol levels as well as shorter luteal phase lengths and lower progesterone levels...

Discussion

Elderly patients with pituitary disease are very different in their GH secretion when compared with age-matched controls. Just to equate a so-called somatopause with pituitary tumour patients that have organic GH deficiency is incorrect. The difference in the 24 h profile is some 90 . The patients with pituitary tumours and organic GH deficiency have a GH reduction of 90 , mainly consisting of a decrease in the amplitude of the GH pulse. This needs to be stated...

Mechanisms of conjoint failure of the somatotropic and gonadal axes in ageing men

Mulligan and C. Y. Bowers Division of Endocrinology, University of Virginia School of Medicine, Charlottesville, Virginia 22908-0202, Endocrine Section, Salem Veterans Affairs Medical Center, Salem, Virginia 24153, Geriatrics and Extended Care Service, McGuire Veterans Affairs Medical Center, Richmond, Virginia 23249, and Department of Medicine SL53, Tulane University Medical Center, New Orleans, Louisiana 70112-2699, USA Abstract. Endogenous growth hormone...

References

Alexandersen P, Haarbo J, Christiansen C 1996 The relationship of natural androgens to coronary heart disease in male a review. Atherosclerosis 125 1 13 Anderson BA 1975 Male age and fertility results from Ireland prior to 1911. Population Index 41 561 567 Ayta IA, McKinlay JB, Krane RJ 1999 The likely worldwide increase in erectile dysfunction between 1995 and 2025 and some possible policy consequences. BJU Int 84 50 56 Brawley OW, Parnes H 2000 Prostate cancer prevention trials in the USA....

Stress and the function of the hypothalamicpituitaryadrenal axis

The hypothalamic pituitary adrenal HPA axis regulates the secretion of cortisol. The net result of the output of cortisol from the adrenals is dependent on central stimulatory events and feedback inhibitory mechanisms. The central regulation takes the shape of a diurnal rhythm, which in humans consists of high activity in the early morning hours and low activity in the afternoon evening. This basic pattern is changed by the experience of a variety of factors which are often grouped together...

Henry G Burger Emma Dudley Pam Mamers David Robertson

Nigel Groome and Lorraine Dennerstein The ageing female reproductive axis I 161 Discussion 167 Jerilynn C. Prior The ageing female reproductive axis II ovulatory changes with perimenopause 172 Discussion 186 Holger Leitolf, Jens Behrends and Georg Brabant The thyroid axis in ageing 193 Discussion 201 Greet Van den Berghe and Stephen M. Shalet Critical illness as a model of hypothalamic ageing 205 Discussion 216 Dariush Elahi, Denis C. Muller, Josephine M. Egan, Reubin Andres, Johannes Veldhuis...