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- Neuroendocrine regulation of autoimmune/inflammatory disease
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Interactions between the immune and nervous systems play an important role in modulating host susceptibility and resistance to inflammatory disease. Neuroendocrine regulation of inflammatory and immune responses and disease occurs at multiple levels: systemically, through the anti-inflammatory action of glucocorticoids released via hypothalamic–pituitary–adrenal axis stimulation; regionally,
through production of glucocorticoids within and sympathetic innervation of immune organs such as the
thymus; locally, at sites of inflammation |
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- Autoimmunity: The Female Connection
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The prevalence of autoimmune diseases in women may be the consequence of a bidirectional signaling network between hormones and the immune system that regulates female reproductive life. Two prototypical autoimmune diseases, rheumatoid arthritis and systemic lupus erythematosus, arise from 2 different immune responses that generate mutually exclusive signals in response to different inflammatory triggers. Certain estrogens may ameliorate the rheumatoid-arthritis-like TH1 response while exacerbating the lupus-like TH2 response. Studies of sex hormone metabolism in lupus patients reveal increased 16-hydroxylation of estrone in some patients and decreased levels of androgens as a result of increased oxidation at C17. These occurrences result in low serum levels of dehydroepiandrosterone (DHEA). Both the increase of 16-hydroxylation of estrone and the depletion of DHEA have immune effects that would tend to exacerbate a lupus-like TH2 response. This theoretical framework provides a rationale for ongoing initial clinical trials of exogenous hormones in autoimmune diseases |
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- Changes Within the Thyroid Axis During the Course of Critical Illness
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Thyroid hormone acts on virtually all cells of the body and has profound effects on many important physiologic processes, such as differentiation, growth, and metabolism.The thyroid axis comprises thyrotropin-releasing hormone (TRH) at the hypothalamic level; thyrotropin at the pituitary level; and thyroxine (T4),triiodothyronine (T3), and reverse T3 (rT3) at the peripheral level.
At the pituitary level, secretion of thyrotropin is stimulated by TRH from the hypothalamus. Thyrotropin is released in secretory bursts superimposed on non-pulsatile secretion and thereby stimulates the thyroid gland to release the prohormone T4 into the circulation. Peripheral conversion of T4 produces the metabolic active hormone, T3, and rT3, which is believed to be metabolically inactive. T4 and T3 in turn exert a negative feedback control on the level of the hypothalamus and the pituitary. |
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- DHEA deficiency syndrome : a new term for old age?
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| Dehydroepiandrosterone (DHEA) is a steroid secreted by the adrenal cortex, with a characteristic, age-related, pattern of secretion. The decline of DHEA concentrations with age has led to the suggestion that old age represents a DHEA deficiency syndrome and that the effects of ageing can be counteracted by DHEA ‘replacement therapy’. DHEA is increasingly being used in the USA, outside medical supervision, for its supposed anti-ageing effects. This commentary weighs the evidence for the existence of a DHEA deficiency syndrome and considers the value of DHEA ‘replacement
therapy' |
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- Effects of Physiological Growth Hormone (GH) Therapy on Cognition and Quality of Life in Patients with Adult-Onset GH
Deficiency
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GH replacement of adults with acquired GH deficiency (GHD) results in body composition changes including increases in lean mass and bone mineral density. However, the effects of long-term GH therapy
on cognitive function are largely unknown, and there are conflicting data regarding quality of life. We performed a randomized, double-blind,
placebo-controlled study of GH replacement in adults with GHD and measured cognition and sense of well-being using standardized psychometric tests before and after therapy.
Forty men (median age 51 yr, range 24–64 yr) with a history of pituitary disease were randomized to GH therapy (starting dose, 10 ±0.3 µg/kg per day: mean treatment dose, 4 ±2 µg/kg per day) vs. placebo for 18 months, and GH doses were adjusted according to serum insulin growth factor-I levels. At baseline, the patients displayed a full-scale intelligence quotient (IQ) score nearly 1 SD above the normal mean.
Mean scores on all cognitive tests fell within normal limits, and on many tests, fell above the mean. On tests of verbal learning and delayed visual memory, mean test scores fell below the mean (although
within normal limits), suggestive of a relative compromise in the area of memory performance.
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- Endogenous Sex Hormones and Cognitive Function in Older Men
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The objective of this study was to determine whether endogenous sex hormone levels predict cognitive function in older men. Our study design was an exploratory analysis in a population-based cohort in
Rancho Bernardo, California. The study participants were 547 community-dwelling men 59–89 yr of age at baseline who were not using testosterone or estrogen therapy. Between 1984 and 1987, sera were
collected for measurement of endogenous total and bioavailable testosterone and estradiol levels.
Between 1988 and 1991, 12 standard neuropsychological instruments were administered, including two
items from the Blessed Information-Memory-Concentration (BIMC) Test, three measures of retrieval from the Buschke-Fuld Selective Reminding Test, a category fluency test, immediate and delayed recall
from the Visual Reproduction Test, the Mini-Mental State Examination with individual analysis of the Serial Sevens and the “World” Backwards components, and the Trail-Making Test Part B. |
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- Glucose-to-Insulin Ratio Rather than Sex Hormone-Binding Globulin and Adiponectin Levels Is the Best Predictor of Insulin Resistance in Nonobese Women with Polycystic Ovary Syndrome
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Polycystic Ovarian disorder (PCOD) in women, has been suggested to be associated with a high risk of developing cardiovascular disease and type 2 diabetes. In many PCOS patients, overweight or central obesity is generally associated with increases in fasting insulin levels, insulin resistance, and glucose intolerance, and has been identified as a target for new therapeutic strategy, including early change in lifestyle.
Early biochemical marker(s) for identifying at-risk patients will be useful for prevention studies. The main goal of the present study was to search for such tool(s). |
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- Growth Hormone (GH)-Deficient Men Are More Responsive to GH Replacement Therapy Than Women
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Thirty-six patients with adult-onset GH deficiency (GHD) were examined before and after 9 months of treatment with recombinant GH. The study was conducted as a double blind, placebo-controlled, 21-month trial with a cross-over design, with each treatment period lasting for 9 months. The same dose, adjusted for body surface area, was given to men (n=21) and women (n=15), and the effects on body
composition and biochemical parameters were evaluated with respect to gender. |
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- Growth hormone : a reproductive
endocrine-paracrine regulator?
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Growth hormone (GH) is not classically considered as a reproductive hormone, although a vast literature indicates that it has roles in reproductive function. It is required for sexual differentiation and pubertal maturation and it participates in gonadal steroidogenesis, gametogenesis and ovulation. GH is also required for fetal nutrition and growth during pregnancy and for mammary development and lactation. |
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- Determinants of cardiovascular risk in 2589 hypopituitary GH-deficient adults
- a KIMS database analysis
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The aim of the present study was to clarify the relationship between GH deficiency (GHD) and
some cardiovascular risk factors and to analyse the effect of GH replacement therapy in a large number
of patients over a prolonged period of time. |
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