Hudson on Ritz - Medalling is not realistic

STFU. wrote:

Quite specious, homegirl.

Am J Physiol Endocrinol Metab. 2006 Jun;290(6):E1078-88. Epub 2005 Dec 27. Links

Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction.Barnholt KE, Hoffman AR, Rock PB, Muza SR, Fulco CS, Braun B, Holloway L, Mazzeo RS, Cymerman A, Friedlander AL.

Clinical Studies Unit, VA Palo Alto Health Care System, 3801 Miranda Ave., Palo Alto, CA 94304, USA.

High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.

Horm Metab Res. 2004 Jan;36(1):27-33. Links

Effects of undernutrition on serum and testicular testosterone levels and sexual function in adult rats.Santos AM, Ferraz MR, Teixeira CV, Sampaio FJ, da Fonte Ramos C.

Urogenital Research Unit, State University of Rio de Janeiro, Rio de Janeiro, Brazil.

The aim of this study was to evaluate testosterone concentrations, sexual behavior, and androgen receptor protein level in the testes of rats submitted to protein- and energy-restricted diets during 30 days. Adult male Wistar rats were assigned to one of the following groups: (C) control, diet with 23% of protein; (PR) protein-restricted, diet with 8% of protein; (ER) energy-restricted, diet with 23% of protein in restricted quantities. Mount number, ejaculation latencies and copulatory efficiency were evaluated to determine sexual behavior. At the end of the experiment, the animals were sacrificed to determine serum and testicular testosterone concentrations as well as testicular androgen receptor protein level. Compared to the C group, the ER group presented a significant decrease in body (36%), testis (20%) and epididymis (14%) weights in serum (78%) and testicular (68%) testosterone concentrations as well as in copulatory efficiency (26%). On the other hand, the ER group presented a significant increase in mount number (114%) and ejaculatory latency (62%). The androgen receptor protein levels were significantly reduced in both PR and ER groups (41% and 74%, respectively). This is the first paper to demonstrate that the effect of undernutrition on reproduction is not related to reduced protein intake but caloric restriction. Also, in caloric restriction, there is a relationship between sex behavior, androgen receptors, and testosterone concentration.

Chronobiol Int. 2005;22(2):253-65.Links

24-hour changes in ACTH, corticosterone, growth hormone, and leptin levels in young male rats subjected to calorie restriction.Chacón F, Esquifino AI, Perelló M, Cardinali DP, Spinedi E, Alvarez MP.

Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense, Madrid, Spain.

Calorie restriction of young male rats increases plasma prolactin, decreases luteinizing hormone (LH) and testosterone, and disrupts their 24 h secretory pattern. To study whether this could be the consequence of stress, we examined the 24 h variations of plasma adrenocorticotropic hormone (ACTH) corticosterone, growth hormone (GH), leptin, and adrenal corticosterone. Rats were submitted to a calorie restriction equivalent to a 66% of usual intake for 4 weeks, starting on day 35 of life. Controls were kept in individual cages and allowed to eat a normal calorie regimen. Significantly lower ACTH levels were detected in calorie-restricted rats. Plasma corticosterone levels during the light phase of the daily cycle were significantly higher in calorie-restricted rats. Time-of-day variation in plasma ACTH and corticosterone levels attained significance in calorie-restricted rats only, with a maximum toward the end of the resting phase. The daily pattern of adrenal gland corticosterone mirrored that of circulating corticosterone; however, calorie restriction reduced its levels. Plasma ACTH and corticosterone correlated significantly in controls only. Calorie restriction decreased plasma GH and leptin, and it distorted 24h rhythmicity. In a second study, plasma ACTH and corticosterone levels were measured in group-caged rats, isolated control rats, and calorie-restricted rats during the light phase of the daily cycle. Plasma ACTH of calorie-restricted rats was lower, and plasma corticosterone was higher, compared with isolated or group-caged controls. The changes in the secretory pattern of hormones hereby reported may be part of the neuroendocrine and metabolic mechanisms evolved to maximize survival during periods of food shortage.

Br J Sports Med. 1986 Jun;20(2):77-81.Links

Are anorexic tendencies prevalent in the habitual runner?Wheeler GD, Wall SR, Belcastro AN, Conger P, Cumming DC.

To investigate whether runners displayed any of the abnormalities characteristic of patients with anorexia nervosa, we conducted a cross sectional study of 31 high mileage, 18 low mileage runners and 18 non-running controls. Subjects completed a personal data questionnaire, the Jackson Personality Inventory (JPI) and the Eating Attitudes Questionnaire (EAT), underwent a body image test and a blood sample was obtained for measurement of reproductive, thyroid and adrenal hormones. High mileage runners scored significantly higher infrequency scores on the JPI than sedentary controls but there was no evidence of psychopathology. The high mileage runners also significantly overestimated waist width and there were small but statistically significant differences in EAT scores between controls and the runner groups. Ten of 49 runners had EAT scores beyond two standard deviations above the mean of non-running controls. Serum total, free and non-specifically bound testosterone and prolactin levels were significantly lower in high mileage runners than controls. LH, FSH, cortisol and thyroid hormones were not significantly different. There were no significant differences in any hormone between low mileage runners and controls. displayed no clear abnormalities characteristic of patients with anorexia The results suggested that running may have a chronic effect on serum testosterone and prolactin levels in high mileage but not low mileage runners. Although there was no significant evidence of anorexia nervosa on testing the runners with EAT, the overestimation of waist size provided some evidence of a distortion of body image in the high mileage runners. Runners displayed no clear abnormalities characteristic of patients with anorexia nervosa.

Exp Clin Endocrinol. 1983 Aug;82(2):160-72.Links

Endocrine study of anorexia nervosa.de Rosa G, Corsello SM, de Rosa E, Della Casa S, Ruffilli MP, Grasso P, Pasargiklian E.

The main objective of the study was to evaluate the endocrinological picture of anorexia. The sample consisted of 23 anorectic patients (20 females, 3 males) with a control group of 10 normal females and 5 normal males. All participants underwent a work-up which included testing for hypothalamic, hypophyseal, thyroidal, adrenal, gonadal functioning and glucose metabolism. Our results revealed a reduced urinary output and low serum levels of gonadotropins with different responses to LHRH correlating with the stage of the illness. We found reduced urinary estrogens and elevated testosterone levels in females. Males demonstrated a reduction of testosterone. While basal prolactinemia was normal in both sexes, males showed an exaggerated response to TRH. The thyroid function study in anorectic patients revealed a decrease in T3 and in free T3 and an increase in reverse T3. Free T4 was slightly increased with normal T4 levels. Basal TSH was normal with a delayed peak after TRH. We also noticed in the anorectic population reduced basal glucose levels with a flat glucose curve; reduced insulin levels with a slight increase after glucose administration; elevated basal GH with a fair response to L-Dopa; elevated serum cortisol with loss of circadian rhythm and slightly inhibited by dexamethasone. In addition, both noradrenalin and VMA were reduced. We concluded that the multiple endocrine abnormalities found are consistent with hypothalamic dysfunction. The etiology of this dysfunction remains for the endocrinologist highly controversial.

J Clin Endocrinol Metab. 1986 Feb;62(2):288-92.Links

Effects of severe dietary restriction on male reproductive hormones.Hoffer LJ, Beitins IZ, Kyung NH, Bistrian BR.

The reproductive hormone response to severe caloric restriction (600 Cal day-1) was studied in six men 33-67% over ideal body weight who completed a 32-day protocol consisting of three periods in the following order: control (4 days), maintenance protein and energy; diet A (14 days), 50 g lean beef protein plus 50 g casein; and diet B (14 days), 50 g lean beef protein plus 50 g carbohydrate. Weight loss (8.7-12.5 kg) was associated with a decrease in mean blood glucose [4.52 +/- 0.60 (+/- SEM), 3.49 +/- 0.29, and 3.80 +/- 0.30 mM] and an increase in beta-hydroxybutyrate (less than 0.10, 2.09 +/- 0.44, and 1.06 +/- 0.34 mM), as determined on the final morning of each period. On the same days, mean serum FSH and LH responses to LHRH infusion of 0.2 micrograms min-1 for 4 h (expressed as milliinternational units per ml area under the concentration-time curve) were: FSH, 1558 +/- 359, 1336 +/- 545, and 1337 +/- 321 (P = NS); and LH, 1730 +/- 545, 1612 +/- 481, and 1782 +/- 556 (P = NS), respectively. Basal serum FSH, LH, free testosterone (T), and total T changed, while 24-h urinary LH and FSH excretion increased on diet A only. Unlike 10 days of total fasting, during which the same amount of weight was lost, basal serum FSH and LHRH-stimulated serum FSH responses were both significantly diminished by 25%, and serum T was diminished by 19% (1), these same parameters were little changed by either low energy diet. The increased urinary excretion of FSH and LH during diet A suggests that greater ketosis increases renal gonadotropin clearance.

Nutrition. 1999 May;15(5):351-8. Links

Differences between men and women as regards the effects of protein-energy malnutrition on the hypothalamic-pituitary-gonadal axis.Lado-Abeal J, Prieto D, Lorenzo M, Lojo S, Febrero M, Camarero E, Cabezas-Cerrato J.

Endocrinology and Nutrition Service, Galician General Hospital, Complejo Hospitalario Universitario de Santiago de Compostela (CHUS), Spain.

joaquin@cif.es

Although protein-energy malnutrition (PEM) affects 50% of hospitalized patients, its effects on the hypothalamic-pituitary-gonadal (HPG) axis have not been extensively investigated. To investigate the effects of PEM on the HPG axis in hospitalized patients, 62 inpatients ages 18-91 y (35 men and 27 women) had a nutritional and hormonal evaluation. Hormones were determined in blood samples obtained between 0700 and 1200 h. Patients were divided into two subgroups: those with body mass index (BMI) ``18.5 kg/m2 (low body mass index [LBMI]; 16 men, 13 women) and those with BMI %%20 kg/m2 (normal-high body mass index [NHBMI]; 19 men, 14 women). The nutritional parameters of LBMI patients were inferior to those of NHBMI patients. Total and free testosterone levels were subnormal, 31.4% and 17.2% respectively, in all men; free testosterone was subnormal in 31.25% of LBMI versus 5.3% of NHBMI male patients and total testosterone concentration was subnormal in 43.8% of LBMI versus 21.1% of NHBMI male patients. Luteinizing hormone (LH) level was higher in LBMI men than in NHBMI men, whereas the reverse was the case for women, for whom follicle-stimulating hormone (FSH) also was lower in the LBMI group than the NHBMI group. The HPG axis hormones which best discriminated between the LBMI and NHBMI groups were free testosterone for men and LH and FSH for women, which were all lower in the LBMI than in the NHBMI group. LH was correlated with BMI and midupper arm muscle circumference (AMC) (women positively and men negatively) but not with triceps skin-fold thickness (TSF). Total testosterone level was positively correlated with AMC and free testosterone with TSF. Hypogonadism is common among hospitalized patients with PEM. Men with PEM have low testosterone levels with normal or high gonadotropin levels, which suggests impairment of Leydig cell function. Women with PEM suffer hypogonadotropic hypogonadism. AMC correlates positively with total serum testosterone concentration in men and with LH levels in women, suggesting that satisfactory function of the HPG axis requires a functional (protein) reserve as well as an energy (fat) reserve.

J Appl Physiol. 2000 May;88(5):1820-30. Links

Endocrine markers of semistarvation in healthy lean men in a multistressor environment.Friedl KE, Moore RJ, Hoyt RW, Marchitelli LJ, Martinez-Lopez LE, Askew EW.

United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760-5007, USA.

Karl.Friedl@det.amedd.army.mil

We tested the hypothesis that key endocrine responses to semistarvation would be attenuated by changing only the food intake in a multistressor environment that also included sustained workload, inadequate sleep, and thermal strain. Serum hormones were compared within and between two groups of healthy young male volunteers participating in the 8-wk US Army Ranger course, with four repeated cycles of restricted energy intakes and refeeding: group 1 (n = 49) and group 2 (n = 48); energy deficits averaged 1,200 and 1,000 kcal/day, respectively. After 8 wk, most of group 1 achieved a minimum body fat, serum 3,5,3'-triiodothyronine (T(3)) was below normal (78 +/- 20 ng/dl), testosterone (T) approached castrate levels (4.5 +/- 3.9 nmol/l), insulin-like growth factor I (IGF-I) declined by one-half (75 +/- 25 microg/l), and cholesterol rose from 158 +/- 31 to 217 +/- 39 mg/dl. Bioavailable T(3) and T were further reduced by increases in their specific binding proteins in response to declining insulin. Refeeding, even with continuation of the other stressors, produced prompt recovery of T(3), T, and IGF-I. Higher energy intakes in group 2 attenuated the subclinical hypothyroidism and hypercholesterolemia, whereas consistent luteinizing hormone suppression indicated centrally mediated threshold effects on gonadal hormone suppression. We conclude that low T, T(3), and IGF-I remained reliable markers of acute energy deficits in the presence of other stressors; elevated cholesterol and cortisol provided information about chronic status, corresponding to diminishing body fat stores.

J Endocrinol. 1989 Jun;121(3):409-17.Links

Effect of short-term starvation on reproductive hormone gene expression, secretion and receptor levels in male rats.Bergendahl M, Perheentupa A, Huhtaniemi I.

Department of Physiology, University of Turku, Finland.

The effects of 4-6 days of food deprivation on the pituitary-testicular function of adult male rats were studied. Fasting decreased body weights on average by 23% (P less than 0.01) and those of seminal vesicles by 55% (P less than 0.01) in 4 days. No consistent changes were found in testicular and ventral prostate weights. The pituitary levels of gonadotrophin-releasing hormone (GnRH) receptors decreased by 50% (P less than 0.01). Serum and pituitary levels of LH, FSH and prolactin decreased by 25-50% (P less than 0.01 for all). Testicular and serum levels of testosterone decreased by 70-80%, testicular LH receptors by 26%, those of prolactin by 50% (P less than 0.01 for all), but those of FSH remained unaffected. Acute (2 h) stimulation by a GnRH agonist (buserelin, 10 micrograms/kg i.m.) resulted in similar LH, FSH and testosterone responses in the fasted and control animals, and human chorionic gonadotrophin (hCG) stimulation (30 IU/kg i.m.) in similar increases in testosterone. A 42% decrease was found in pituitary content of mRNA of the common alpha subunit (P less than 0.05), but the mRNAs of the LH- and FSH-beta chains and prolactin were unaffected by fasting for 4 days. When the same mRNAs were measured after 6 days of fasting, the decrease of the mRNA of FSH-beta also became significant (50%, P less than 0.01). In contrast, the mRNA of LH-beta was increased twofold (P less than 0.01) at this time and serum LH levels were similar in control and starved animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Baillieres Clin Endocrinol Metab. 1987 May;1(2):299-317.Links

Physical exercise and the neuroendocrine control of reproduction.Prior JC.

Reproductive change during conditioning exercise (physical training provides a model of hypothalamic adaptation to alterations in the external and internal environment. Parallels exist between the reproductive changes with exercise and those occurring with physical illness, undernutrition and psychological trauma. Although menstrual cyclicity may be disrupted in younger women, luteal phase shortening, anovulation and decreased premenstrual symptoms within normal ovulatory cycles are the most frequent observations noted. Baseline LH, prolactin and oestradiol tend to be lower, and other hormones unchanged, in trained women. Testosterone may be decreased within the normal range in men. Recent evidence shows that LH pulse frequency, amplitude and area under the LH curve are decreased in both female and male runners. Interrelationships between increases in central dopamine, endorphin and probably some hypothalamic message(s) relating to nutritional state appear to modulate these reproductive changes. The clinical and therapeutic response to reproductive alterations in the context of exercise differs when these are seen as adaptive and not as disease processes (Prior and Vigna, 1985b).