scholarly journals Erosion of Endogenous Testosterone-Driven Negative Feedback on Pulsatile Luteinizing Hormone Secretion in Healthy Aging Men

2004 ◽  
Vol 89 (11) ◽  
pp. 5753-5761 ◽  
Author(s):  
Johannes D. Veldhuis ◽  
Ali Iranmanesh ◽  
Daniel M. Keenan
Keyword(s):  
Successful Aging ◽  
Healthy Aging ◽  
Time Lag ◽  
Hormone Secretion ◽  
Biological Marker ◽  
Sex Hormone Binding Globulin ◽  
Optimal Time ◽  
Elderly Subjects ◽  
Luteinizing Hormone Secretion ◽  
Aging Men

Abstract The present study tests the intuition that successful aging in men is marked by: 1) impaired feedforward by endogenous LH concentrations (con) of testosterone (Te) secretion (sec); and/or 2) attenuated feedback by unmanipulated Te con of LH sec. The goal was to assess both implicit linkages analytically without disrupting normal pathway coupling. This strategy required: 1) assay of paired LH and Te con sampled every 10 min for 24 h in 13 older (O) (ages 60–78 yr) and 13 young (Y) (ages 18–30 yr) men; 2) deconvolution-based estimation of LH and Te sec rates; 3) lag-specific cross-correlation analyses of the relationships between LH and Te con and sec; and 4) statistical contrasts by age stratum. Salient outcomes were: 1) O and Y men maintain comparable LH con drive of Te sec, viz maximal r = +0.51 and r = +0.52, respectively, at an optimal time lag of 50 min (both P < 0.001 against random LH and Te associations); 2) elderly subjects exhibit reduced Te con inhibition of LH sec [minimal r = −0.008 (O) vs. r = −0.10 (Y), P < 0.01 at a time lag of 40 min]; 3) mean (24-h) LH con do not differ by age; and 4) molar Te/sex hormone-binding globulin con are lower in the elderly than in Y individuals (P < 0.01). In conclusion, noninvasive analyses predict that attenuation of endogenous Te feedback restraint on the hypothalamo-pituitary unit may be an early biological marker of adaptive changes in the GnRH-LH-Te ensemble axis in the healthy O male.

Long-term testosterone supplementation augments overnight growth hormone secretion in healthy older men

2007 ◽  
Vol 293 (3) ◽  
pp. E769-E775 ◽  
Author(s):  
Ranganath Muniyappa ◽  
John D. Sorkin ◽  
Johannes D. Veldhuis ◽  
S. Mitchell Harman ◽  
Thomas Münzer ◽  
...  
Keyword(s):  
Healthy Aging ◽  
Low Dose ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Older Men ◽  
Gh Secretion ◽  
Aging Men ◽  
Igf I ◽  
Igfbp 3

Circulating testosterone (T) and GH/IGF-I are diminished in healthy aging men. Short-term administration of high doses of T augments GH secretion in older men. However, effects of long-term, low-dose T supplementation on GH secretion are unknown. Our objective was to evaluate effects of long-term, low-dose T administration on nocturnal GH secretory dynamics and AM concentrations of IGF-I and IGFBP-3 in healthy older men (65–88 yr, n = 34) with low-normal T and IGF-I. In a double-masked, placebo-controlled, randomized study we assessed effects of low-dose T supplementation (100 mg im every 2 wk) for 26 wk on nocturnal GH secretory dynamics [8 PM to 8 AM, Q20 min sampling, analyzed by multiparameter deconvolution and approximate entropy (ApEn) algorithms]. The results were that T administration increased serum total T by 33% ( P = 0.004) and E2 by 31% ( P = 0.009) and decreased SHBG by 17% ( P = 0.002) vs. placebo. T supplementation increased nocturnal integrated GH concentrations by 60% ( P = 0.02) and pulsatile GH secretion by 79% ( P = 0.05), primarily due to a twofold increase in GH secretory burst mass ( P = 0.02) and a 1.9-fold increase in basal GH secretion rate ( P = 0.05) vs. placebo. There were no significant changes in GH burst frequency or orderliness of GH release (ApEn). IGF-I levels increased by 22% ( P = 0.02), with no significant change in IGFBP-3 levels after T vs. placebo. We conclude that low-dose T supplementation for 26 wk increases spontaneous nocturnal GH secretion and morning serum IGF-I concentrations in healthy older men.

Longitudinal Changes in Individual BrainAGE in Healthy Aging, Mild Cognitive Impairment, and Alzheimer’s Disease

GeroPsych ◽  
2012 ◽  
Vol 25 (4) ◽  
pp. 235-245 ◽  
Author(s):  
Katja Franke ◽  
Christian Gaser
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Healthy Aging ◽  
Brain Aging ◽  
Elderly Subjects ◽  
Additional Increase ◽  
Longitudinal Changes ◽  
Novel Method ◽  
The Brain

We recently proposed a novel method that aggregates the multidimensional aging pattern across the brain to a single value. This method proved to provide stable and reliable estimates of brain aging – even across different scanners. While investigating longitudinal changes in BrainAGE in about 400 elderly subjects, we discovered that patients with Alzheimer’s disease and subjects who had converted to AD within 3 years showed accelerated brain atrophy by +6 years at baseline. An additional increase in BrainAGE accumulated to a score of about +9 years during follow-up. Accelerated brain aging was related to prospective cognitive decline and disease severity. In conclusion, the BrainAGE framework indicates discrepancies in brain aging and could thus serve as an indicator for cognitive functioning in the future.

Androgenic and oestrogenic steroid participation in feedback control of luteinizing hormone secretion in male sheep

1983 ◽  
Vol 102 (4) ◽  
pp. 499-504 ◽  
Author(s):  
M. J. D'Occhio ◽  
B. D. Schanbacher ◽  
J. E. Kinder
Keyword(s):  
Luteinizing Hormone ◽  
Pulse Generator ◽  
Hormone Secretion ◽  
Pulse Interval ◽  
Serum Concentrations ◽  
Luteinizing Hormone Secretion ◽  
Lh Release ◽  
Lh Secretion ◽  
Additional Feedback ◽  
Male Sheep

Abstract. The acute castrate ram (wether) was used as an experimental model to investigate the site(s) of feedback on luteinizing hormone (LH) by testosterone, dihydrotestosterone and oestradiol. At the time of castration, wethers were implanted subdermally with Silastic capsules containing either crystalline testosterone (three 30 cm capsules), dihydrotestosterone (five 30 cm capsules) or oestradiol (one 6.5 cm capsule). Blood samples were taken at 10 min intervals for 6 h 2 weeks after implantation to determine serum steroid concentrations and to characterize the patterns of LH secretion. Pituitary LH response to exogenous LRH (5 ng/kg body weight) were also determined at the same time. The steroid implants produced serum concentrations of the respective hormones which were either one-third (testosterone) or two-to-four times (dihydrotestosterone, oestradiol) the levels measured in rams at the time of castration. Non-implanted wethers showed rhythmic pulses of LH (pulse interval 40–60 min) and had elevated LH levels (16.1 ± 1.6 ng/ml; mean ± se) 2 weeks after castration. All three steroids suppressed pulsatile LH release and reduced mean LH levels (to below 3 ng/ml) and pituitary LH responses to LRH. Inhibition of pulsatile LH secretion by all three steroids indicated that testosterone as well as its androgenic and oestrogenic metabolites can inhibit the LRH pulse generator in the hypothalamus. Additional feedback on the pituitary was indicated by the dampened LH responses to exogenous LRH.

A study of luteinizing hormone secretion in the cow

Reproduction ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 135-136 ◽  
Author(s):  
L. Cummins ◽  
M. Blockey ◽  
J. Brown ◽  
Goding
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

scholarly journals Exploring Aging Masculinities From Different Disciplines and Perspectives

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 825-825
Author(s):  
Liat Ayalon ◽  
Josep Armengol ◽  
Michael Kimmel
Keyword(s):  
Social Sciences ◽  
American Literature ◽  
Successful Aging ◽  
Older Men ◽  
Contemporary American Literature ◽  
The Social ◽  
Aging Men ◽  
Personal Experiences ◽  
And Gender ◽  
Types Of Information

Abstract Traditionally, gerontology research has been relatively genderless. When the intersection of age and gender was explored, this was done primarily by focusing on the experiences of older women. Much less is known about the experiences of older men. The present symposium brings together work from the humanities and the social sciences in order to explore societal images and personal experiences of aging men. The paper by Maierhofer and Ratzenböck provides a theoretical outlook on this intersection from the humanities perspective, followed by empirical applications from the social sciences. Next, Armengol uses contemporary American literature to challenge the traditional stereotype of decline in sexuality and masculinity. The paper by Ni Leime & O’Neill examines stereotypes of aging masculinities, but this time from the perspective of older men as the audience who react to their portrayal in visual culture. Finally, Ayalon and Gweyrtz-Meydan present ethical dilemmas faced by physicians who treat older men’s sexuality in light of active marketing campaigns of the pharmaceutical industry, which advocate for a model of successful aging and ongoing sexual intercourse. The discussant, Kimmel, will conceptualize the four papers by stressing the different types of information that can be obtained via different methods of inquiry. The complementary information provided by the different papers and the integration of methods and findings from the humanities with the social sciences will be discussed.

Opioid Control of Luteinizing Hormone Secretion in Patients with Hirsutism and Hyperandrogenemia

1987 ◽  
Vol 23 (2) ◽  
pp. 117-121 ◽  
Author(s):  
Felice Petraglia ◽  
Susanna Golinelli ◽  
Gerardo d’Ambrogio ◽  
Giuseppina Comitini ◽  
Fabio Facchinetti ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Luteinizing Hormone Secretion

Changes in the characteristics of pulsatile luteinizing hormone secretion during the oestrous cycle and after ovariectomy and oestrogen treatment in female rats

1982 ◽  
Vol 94 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Takashi Higuchi ◽  
Masazumi Kawakami
Keyword(s):  
Hormone Secretion ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Luteinizing Hormone Secretion ◽  
Oestrogen Treatment ◽  
Serum Lh ◽  
Lh Release

Changes in the characteristics of LH secretory pulses in female rats were determined in different hormonal conditions; during the oestrous cycle and after ovariectomy and oestrogen treatment. The frequency and amplitude of the LH pulses were stable during the oestrous cycle except at oestrus when a pattern could not be discerned because of low LH concentrations. These were significantly lower than those measured during other stages of the cycle. Mean LH concentrations and LH pulse amplitudes increased with time up to 30 days after ovariectomy. The frequency of the LH pulse was unchanged 4 days after ovariectomy when mean LH levels had already increased. The frequency increased 10 days after ovariectomy and then remained stable in spite of a further increase in mean serum LH concentrations. Oestradiol-17β injected into ovariectomized rats caused a decrease in LH pulse amplitude but no change in pulse frequency. One day after treatment with oestradiol benzoate no LH pulse was detectable, probably because the amplitude was too small. A generator of pulsatile LH release is postulated and an oestrogen effect on its function is discussed.

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