Posts tagged pituitary gland
Articles and news from the latest research reports.
Neurons Can Use Local Stores for Communication Needs
Researchers reveal that neurons can utilize a supremely localized internal store of calcium to initiate the secretion of neuropeptides, one class of signaling molecules through which neurons communicate with each other and with other cells. The study appears in The Journal of General Physiology.
(Image caption: Localization of ryanodine receptors (red) in an isolated nerve terminal from the posterior pituitary gland. Image credit: McNally et al., 2014)
Neuropeptides are released from neurons through a process that—like other secretory events—is triggered primarily by the influx of calcium into the neuron through voltage-gated channels. Although neuropeptides are stored in large dense core vesicles (LDCVs) that also contain large amounts of calcium, it has been unclear whether these locally based calcium supplies can also be used to modulate secretion.
A team of researchers led by José Lemos from the University of Massachusetts Medical School examined the mechanisms at play during secretion of vasopressin from nerve terminals in the posterior pituitary gland, which releases the neuropeptide into the blood so that it can make its way to the kidney and regulate water retention. The researchers found that certain intracellular calcium channels known as ryanodine receptors are likely responsible for mobilizing calcium from LDCVs to facilitate vasopressin release. The findings indicate that neurons have a greater capacity than previously appreciated to fine-tune the release of neuropeptides and thereby their communications with other cells.
(Source: newswise.com)
Soldiers with blast injuries suffer pituitary hormone problems
Researchers studying British soldiers who fought in Afghanistan have highlighted hormonal problems that commonly result from blast injuries.
Soldiers with injuries affecting the pituitary gland may suffer psychological and metabolic symptoms which impede their recovery.
The researchers, from Imperial College London and the Royal Centre for Defence Medicine, say identifying these sufferers will enable them to receive appropriate hormone replacement therapy.
The research was funded by the Medical Research Council is published in the journal Annals of Neurology.
The study looked at 19 British soldiers with moderate to severe brain injury caused by blasts from improvised explosive devices (IEDs) while on duty in Afghanistan, and a group of 39 individuals with moderate to severe traumatic brain injuries caused by road traffic accidents, falls and assaults.
It found that a much higher proportion of soldiers with blast injuries had pituitary hormone problems (32 per cent) than in the non-blast control group (2.6 per cent).
One in five of the soldiers ended up receiving hormone treatment with growth hormone, testosterone and/or hydrocortisone – a replacement for the stress hormone cortisol.
The study also showed that the soldiers who had pituitary dysfunction following blast injury had more severe damage to white matter connections within the brain, and more severe cognitive problems, such as being slow in processing information, than those who did not have hormone problems.
The recent conflicts in Iraq and Afghanistan have seen rapid advances in personal protective equipment and in the medical management of severe trauma. These gains have meant that increasing numbers of soldiers are surviving previously fatal and complex injuries.
Injuries caused by IEDs are so numerous that they have been called the ‘signature injury’ of these conflicts. Between December 2009 and March 2012, 183 UK soldiers survived a moderate to severe blast traumatic brain injury in Afghanistan. The number of such injuries among US troops is much higher. The complex physical forces involved in a blast have led to much speculation about how the blast wave itself causes brain injury.
Dr Tony Goldstone, from the MRC Clinical Sciences Centre at Imperial College London, who led the study, said: “This study was set up to see if there were facets unique to the kind of trauma caused to the brain by IEDs. We found that there was a high prevalence of hormonal problems in soldiers with these kinds of injuries.
“This study involved a relatively small number of soldiers, and so assessment of additional patients will be needed to confirm such a prevalence rate. However the results do emphasise the importance of actively screening for pituitary problems in all soldiers and others who have had moderate to severe brain injury from exposure to blast. This will enable identification of those who may benefit from hormonal treatments to aid their rehabilitation, recovery and quality of life.”
The patients were treated in the multi-disciplinary traumatic brain injury clinic at the Imperial Centre for Endocrinology at Imperial College Healthcare NHS Trust and scanned at the Computational, Cognitive and Clinical Neuroimaging Laboratory at Imperial College London by Professor David Sharp and Major David Baxter.
Air Marshal Paul Evans, Surgeon General said: “I fully support the research that has been undertaken by Imperial College London and the Ministry of Defence. As Surgeon General, I am committed to ensuring Service personnel benefit from the latest advances in medical research and we continue to conduct research into traumatic brain injury with colleagues at Imperial College London as well as our US and other NATO partners. A Defence Medical Services working group identifies priority areas for TBI research and MOD policy continues to be reviewed in light of emerging best practice. Working in partnership will ensure our personnel benefit as well as enable best practice to be shared between the MOD and NHS.”
Professor David Lomas, Chair of the MRC’s Population and Systems Medicine Board, which funded the research, said: “Trauma is a serious health problem that has a major impact on people in both a civilian and military setting. By linking academic and military research programmes through studies such as this we will build a greater understanding of acute trauma that will inform future approaches to trauma management, to ensure that people suffering major injury receive the most advanced specialist care.”