A5088392007- Hormonal and reproductive studies
- Sperm and Testicular Function
- Hypothalamic control of reproductive hormones
- Reproductive Biology and Fertility
- Ovarian function and disorders
- Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities
- Sexual Differentiation and Disorders
- Estrogen and related hormone effects
- Growth Hormone and Insulin-like Growth Factors
- Testicular diseases and treatments
- Birth, Development, and Health
- Ovarian cancer diagnosis and treatment
- Muscle metabolism and nutrition
- Animal Genetics and Reproduction
- Reproductive System and Pregnancy
- Effects and risks of endocrine disrupting chemicals
- Receptor Mechanisms and Signaling
- Hormonal Regulation and Hypertension
- Prostate Cancer Treatment and Research
- Stress Responses and Cortisol
- Vitamin D Research Studies
- Reproductive Physiology in Livestock
- Bone health and osteoporosis research
- Sexual function and dysfunction studies
- Pharmacological Effects and Assays
Imperial College London
2016-2025
University of Turku
2016-2025
Hammersmith Hospital
2014-2024
The London College
2006-2023
Lund University
2022
National Institutes of Health
1979-2020
Yale University
2020
Harvard University
2020
Rockefeller University
2020
Brigham and Women's Hospital
2020
The association between aging-related testosterone deficiency and late-onset hypogonadism in men remains a controversial concept. We sought evidence-based criteria for identifying the general population on basis of an symptoms low level.
Abstract Context: The cause of declining testosterone (T) in aging men and their relationships with risk factors are unclear. Objective: objective the study was to investigate between lifestyle health reproductive hormones men. Design: This a baseline cross-sectional survey on 3200 community-dwelling aged 40–79 yr from prospective cohort eight European countries. Results: Four predictors were associated distinct modes altered function: 1) age: lower free T (FT; −3.12 pmol/liter·yr, P...
In the mammalian ovary, progressive activation of primordial follicles from dormant pool serves as source fertilizable ova. Menopause, or end female reproductive life, occurs when follicle is exhausted. However, molecular mechanisms underlying are poorly understood. We provide genetic evidence that in mice lacking PTEN (phosphatase and tensin homolog deleted on chromosome 10) oocytes, a major negative regulator phosphatidylinositol 3-kinase (PI3K), entire becomes activated. Subsequently, all...
Context: The diagnosis of late-onset hypogonadism (LOH) in older men with age-related declines testosterone (T) is currently not well characterized. Objective: Our objective was to investigate whether different forms can be distinguished among aging men. Design: study a cross-sectional survey on 3369 community-dwelling aged 40–79 yr eight European centers. Methods: Four groups subjects were defined: eugonadal (normal T and normal LH), secondary (low low/normal primary elevated compensated...
To study further the role of gonadotropins in reproductive functions, we generated mice with LH receptor (LHR) knockout (LuRKO) by inactivating, through homologous recombination, exon 11 on LHR gene. LuRKO males and females were born phenotypically normal, testes, ovaries, genital structures indistinguishable from their wild-type (WT) littermates. Postnatally, testicular growth descent, external accessory sex organ maturation, blocked males, spermatogenesis was arrested at round spermatid...
The separation of the prepuce from glans penis, termed preputial separation, has been shown to be androgen dependent and occur around time puberty in rats. In present studies mean ages four experiments were 39, 42, 44 45 days age, just preceding appearance mature sperm caput epididymis. Preputial occurred prior significant increase circulating levels by Day 51 as measured radioimmunoassay. However, castration late 35 blocked demonstrating that was on continued presence a low level androgen....
To investigate further brain-pituitary-gonadal interrelationships we have generated mice in which the gene encoding FSH receptor has been disrupted. Female knockout (FSHRKO) were infertile. The ovaries significantly reduced size, with follicular development arrested at preantral stage, but there was evidence of stromal hypertrophy. vagina imperforate, and uterus atrophic. There no response to administration PMSG. Inhibins A B undetectable both serum gonads. Compared those control animals,...
Health and lifestyle factors are associated with variations in serum testosterone levels ageing men. However, it remains unclear how age-related changes may be attenuated by modifications. The objective was to investigate the longitudinal relationships between health hormones of reproductive endocrine axis men.A survey 2736 community-dwelling men aged 40-79 years at baseline recruited from eight centres across Europe. Follow-up assessment occurred mean (±S.D.) 4.4±0.3 later.Paired results...
To maintain the female reproductive lifespan, majority of ovarian primordial follicles are preserved in a quiescent state order to provide ova for later life. However, molecular mechanism that maintains long quiescence is poorly understood. Here we genetic evidence show tumor suppressor tuberous sclerosis complex 1 (Tsc1), which negatively regulates mammalian target rapamycin (mTORC1), functions oocytes follicles. In mutant mice lacking Tsc1 gene oocytes, entire pool activated prematurely...
Late-onset hypogonadism (LOH) has been defined as a syndrome in middle-aged and elderly men reporting symptoms the presence of low testosterone (T). The objective study was to seek biochemical end-organ evidence androgen deficiency classified having LOH according our previously published criteria. design included cross-sectional data from European Male Aging Study on 2966 community-dwelling aged 40–79 years eight countries. Waist circumference, body mass index, muscle mass, estimated heel...
Strong overexpression of anti-Müllerian hormone (AMH) in transgenic mice leads to incomplete fetal virilization and decreased serum testosterone the adult. Conversely, AMH-deficient exhibit Leydig cell hyperplasia. To probe mechanism action AMH on steroidogenesis, we have studied expression mRNA for steroidogenic proteins vivo vitro performed a morphometric analysis testicular tissue overexpressing hormone. We show that male blocks differentiation precursors. Expression protein mRNAs, mainly...
We have developed an immunofluorometric assay (IFMA) for rat (r) LH, which is based on two monoclonal antibodies, one to bovine and the other human LH. Signal detection occurs by time-resolved fluorescence evoked a europium label (Delfia, Wallac). The method fast in comparison standard RIA with NIDDK reagents (4 h vs. 3 days). sensitivity of IFMA (0.75 pg/tube; rLH RP-2) over 30-fold higher than that (usual limit, 20-30 pg/tube). Using 25-microliters serum samples, 0.03 micrograms/liter;...