Endocrine Regulation of Spermatogenesis in Mammals

2015 ◽  
pp. 94-113
Keyword(s):  
Endocrine Regulation

Nutrient Uptake and Endocrine Regulation of Milk Synthesis by Mammary Tissue of Lactating Sows

1995 ◽  
Vol 73 (suppl_2) ◽  
pp. 36 ◽  
Author(s):  
Dean R Boyd ◽  
Ronald S Kensinger ◽  
Robert J Harrell ◽  
Dale E Bauman
Keyword(s):  
Nutrient Uptake ◽  
Mammary Tissue ◽  
Endocrine Regulation ◽  
Lactating Sows

scholarly journals A prospective, observational clinical trial on the impact of COVID-19-related national lockdown on thyroid hormone in young males

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giulia Brigante ◽  
Giorgia Spaggiari ◽  
Barbara Rossi ◽  
Antonio Granata ◽  
Manuela Simoni ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Serum Levels ◽  
Stressful Event ◽  
Italian Population ◽  
Reference Ranges ◽  
Endocrine Regulation ◽  
Before And After ◽  
Hpt Axis ◽  
The Impact

AbstractTrying to manage the dramatic coronavirus disease 2019 (COVID-19) infection spread, many countries imposed national lockdown, radically changing the routinely life of humans worldwide. We hypothesized that both the pandemic per se and the consequent socio-psychological sequelae could constitute stressors for Italian population, potentially affecting the endocrine system. This study was designed to describe the effect of lockdown-related stress on the hypothalamic-pituitary-thyroid (HPT) axis in a cohort of young men. A prospective, observational clinical trial was carried out, including patients attending the male infertility outpatient clinic before and after the national lockdown for COVID-19 pandemic. The study provided a baseline visit performed before and a follow-up visit after the lockdown in 2020. During the follow-up visit, hormonal measurements, lifestyle habits and work management were recorded. Thirty-one male subjects were enrolled (mean age: 31.6 ± 6.0 years). TSH significantly decreased after lockdown (p = 0.015), whereas no significant changes were observed in the testosterone, luteinising hormone, follicle-stimulating hormone, estradiol and prolactin serum levels. No patient showed TSH serum levels above or below reference ranges, neither before nor after lockdown. Interestingly, TSH variation after lockdown was dependent on the working habit change during lockdown (p = 0.042). We described for the first time a TSH reduction after a stressful event in a prospective way, evaluating the HPT axis in the same population, before and after the national lockdown. This result reinforces the possible interconnection between psychological consequences of a stressful event and the endocrine regulation.

scholarly journals Aromatase inhibitors in breast cancer.

2004 ◽  
Vol 11 (2) ◽  
pp. 179-189 ◽  
Author(s):  
P E L√∏nning
Keyword(s):  
Breast Cancer ◽  
Aromatase Inhibitors ◽  
Cancer Biology ◽  
Postmenopausal Breast Cancer ◽  
Phase Iii ◽  
Cross Resistance ◽  
Consistent Difference ◽  
Clinical Effects ◽  
Endocrine Regulation

The development of aromatase inhibitors for breast cancer therapy is a result of successful translational research exploring the biochemical effects of different compounds in vivo. Studies assessing plasma oestrogen levels as well as in vivo aromatase inhibition have revealed a consistent difference with respect to biochemical efficacy between the third generation compounds (anastrozole, letrozole and exemestane) and the previous, first and second generation drugs, corresponding to the improved clinical effects of these compounds as outlined in large phase III studies. Thus, endocrine evaluation has been found to be a valid surrogate parameter for clinical efficacy. Moreover, the results from these studies have added important biological information to our understanding of endocrine regulation of breast cancer. Based on the clinical results so far, aromatase inhibitors are believed to play a key role in future adjuvant therapy of postmenopausal breast cancer patients and potentially also for breast cancer prevention. Interesting findings such as the lack of cross-resistance between steroidal and non-steroidal compounds should be further explored, as this may add additional information to our understanding of breast cancer biology.

scholarly journals Transcriptional responses in jejunum of two layer chicken strains following variations in dietary calcium and phosphorus levels

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Henry Reyer ◽  
Michael Oster ◽  
Siriluck Ponsuksili ◽  
Nares Trakooljul ◽  
Adewunmi O. Omotoso ◽  
...  
Keyword(s):  
Vitamin D ◽  
High Performance ◽  
Absorption Capacity ◽  
Egg Laying ◽  
Endocrine Regulation ◽  
Transcriptional Responses ◽  
Endogenous Factors ◽  
Mineral Homeostasis ◽  
Laying Performance ◽  
Vitamin D Levels

Abstract Background Calcium (Ca) and phosphorus (P) are essential nutrients that are linked to a large array of biological processes. Disturbances in Ca and P homeostasis in chickens are associated with a decline in growth and egg laying performance and environmental burden due to excessive P excretion rates. Improved utilization of minerals in particular of P sources contributes to healthy growth while preserving the finite resource of mineral P and mitigating environmental pollution. In the current study, high performance Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) hens at peak laying performance were examined to approximate the consequences of variable dietary Ca and P supply. The experimental design comprised four dietary groups with standard or reduced levels of either Ca or P or both (n = 10 birds per treatment group and strain) in order to stimulate intrinsic mechanisms to maintain homeostasis. Jejunal transcriptome profiles and the systemic endocrine regulation of mineral homeostasis were assessed (n = 80). Results Endogenous mechanisms to maintain mineral homeostasis in response to variations in the supply of Ca and P were effective in both laying hen strains. However, the LSL and LB appeared to adopt different molecular pathways, as shown by circulating vitamin D levels and strain-specific transcriptome patterns. Responses in LSL indicated altered proliferation rates of intestinal cells as well as adaptive responses at the level of paracellular transport and immunocompetence. Endogenous mechanisms in LB appeared to involve a restructuring of the epithelium, which may allow adaptation of absorption capacity via improved micro-anatomical characteristics. Conclusions The results suggest that LSL and LB hens may exhibit different Ca, P, and vitamin D requirements, which have so far been neglected in the supply recommendations. There is a demand for trial data showing the mechanisms of endogenous factors of Ca and P homeostasis, such as vitamin D, at local and systemic levels in laying hens.

INTRAPANCREATIC REGULATION OF HORMONE SECRETION IN THE DOMESTIC FOWL, GALLUS DOMESTICUS

1978 ◽  
Vol 76 (3) ◽  
pp. 449-459 ◽  
Author(s):  
R. L. HAZELWOOD ◽  
D. R. LANGSLOW
Keyword(s):  
Uric Acid ◽  
Gastric Juice ◽  
Free Acid ◽  
Hormone Secretion ◽  
Volume Flow ◽  
Endocrine Regulation ◽  
Hormone Release ◽  
Endocrine Secretion ◽  
Temporal Basis ◽  
Chicken Pancreas

The intrapancreatic endocrine regulation of hormone secretion by the chicken pancreas was studied. Fasted adult male chickens were prepared surgically for the collection of 'gastric' juice and blood samples from the femoral artery. Avian hormone preparations of insulin, glucagon and pancreatic polypeptide (APP) were injected at doses of 50 μg hormone/ kg body wt. Immunoassays of insulin, glucagon and APP were carried out on plasma, as were analyses for glucose, uric acid and free fatty acids (FFA). Gastric juice was analysed for volume flow and total protein, free acid and pepsin concentrations. Injection of insulin decreased all gastric parameters markedly (in contrast to its effect in mammals) and also increased the concentrations of FFA, glucagon (a bimodal response) and uric acid. The increases in levels of FFA, glucagon and uric acid occurred as early as 2·5 min after injection and considerably before significant hypoglycaemia was induced (15–30 min). Injection of glucagon caused a modest decrease in the volume of gastric secretion, but had little other effect except for a small increase in the amount of pepsin released. At 2·5 min, glucagon gave rise to a significant increase in the levels of insulin and FFA in the plasma, and after 15 min the levels of glucose and uric acid had also increased. A progressive decrease in the concentration of APP in the plasma was observed, which was greatest after 15 min and was 28% below control values. In all respects, APP was a powerful avian gastric secretogogue, but had no effect on the concentrations of plasma glucose and insulin. Whereas APP decreased the concentration of FFA in the plasma immediately, the peptide increased both the total and pancreatic levels of immunoreactive glucagon by 50% within 2·5 min, and this increase was even greater at 15 min. Collectively, the results obtained indicate, on a temporal basis, that intrapancreatic regulation of endocrine secretion occurs in Aves and that the release phenomena produce an immediate response. Subsequent or secondary hormone release may occur in response to peripheral metabolic events, especially those requiring homeostatic corrective measures.

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