Course code: vbb 301 course title: Biochemistry of Hormones & Disease number of units
Download 473.3 Kb. Pdf ko'rish
|
Biochemistry of Hormones & Disease
- Bu sahifa navigatsiya:
- Neuroendocrine or hormonal Theory;
- Mitochondria theory
Evolution theory; here it is suggested that that longevity is a product of evolutionary forces e.g.
body weight brain weight and flight e.t.c different species of animals have different life span, this provides evidence that longevity is genetically influenced. All adaptations that afford protection from predators and other hazards e.g. spines in porcupines justify greater developmental resources to build more durable animal and a longer maximum lifespan. Neuroendocrine or hormonal Theory; this theory Suggests the role of specific hormones in the aging process, notably cortisol, a hormone known to increase as organisms age and plays crucial role in stress; estrogen and so on. Generally it is known that the hypothalamus loses it precision regulatory ability and the receptors which uptake individual hormones become less sensitive to them. Accordingly, with increasing age the secretion of many hormones declines and their effectiveness (compared unit to unit) is also reduced due to the receptors down-grading. Telomere or Telomerase Theory of Aging. Telomeres (the sequences of nucleic acids extending from the ends of chromosomes), shorten every time a cell divides. This shortening of telomeres is believed to lead to cellular damage due to the inability of the cell to duplicate itself correctly. Each time a cell divides it duplicates itself a little worse than the time before, thus this eventually leads to cellular dysfunction, aging and indeed death. Telomerase is an enzyme that appears to repair and replace telomeres helping to re-regulate the clock that controls the life-span of dividing cells, it is found only in germ and cancer cells. Mitochondria theory; this theory is closely related to the free radical theory but emphasis of damage by FRs is placed on the mitochondria which is the power house of the cell where most endogenous generation of FRs occur. Mitochondria are the only cellular organelles possessing http://www.unaab.edu.ng their own DNA, these DNA unlike nuclear DNA do not have protective heat shock and histone proteins, also lack DNA repair mechanisms, hence are liable to quick damage by FRs. The mitochondrial theory of AGING postulates that damage to mitDNA occur at a rate 10-20 times more than damage to nuclear DNA due to deficiencies in the oxidative phosphorylative pathway leading to loss of mitochondria functions ( mitDNA code for the protein complexes of the electron transport chain) and imminently cellular function ( due to insufficient production of energy). About 1-2% of oxygen leak from the respiratory chain to for reactive oxygen species. Download 473.3 Kb. Do'stlaringiz bilan baham: |
Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling
ma'muriyatiga murojaat qiling