Magnesium Flashcards
biochem function
Mg is cofactor for 300+ enzyme systems
indirectly (Mg-ATP complex): glucose + ATP(Mg2+) –> Glucose -6- P + ADP
directly as enzyme activator
physiologic modulator
- coupling of enzymes/NTs to receptors
- (+) of G proteins and adenylate cyclase
- modulates ion channels
excretion
affected by alcohol, loop diuretics, cisplatin, Abx, digitalis
GI absorption
carrier mediated + diffusion, (+) by calcitriol
causes of deficiency: GI
GI: inadequate diet, prolonged IV, long term gastric drainage/ intestinal fistulae, prolonged diarrhea/ vomiting, malabsorption, acute severe pancreatitis, alcohol abuse
causes of deficiency: Renal
diuretic therapy, some kidney diseases
causes of deficiency: Endocrine
diabetes, primary hyperthyroidism, aldosteronism, inc lactation
symptoms of deficiency: CNS
hard to remember, concentrate, apathy, depression, confusion, hallucinations, paranoia
symptoms of deficiency: Neuromuscular
numbness, tingling, cramps, muscular weakness, tremor, ataxia, nystagmus, tetany, hypocalcemia, hypokalemia, cardiac arrhythmias, heart attack
Mg effect on BP
Mg given w/ diuretic lowers BP
Mg effect on CVD
lowers CVD risk and lowers BP
Mg effect on diabetes
role in insulin action, glycemic control
Mg effect on Osteoporosis
inc BMD, inc Ca utilization
Who needs extra Mg
meds: loop + thiazide diuretics, Abx, anti- neoplastic meds, long term use of PPI, poorly controlled diabetes, alcoholics, malabsorption, elderly
low ICF Mg + insulin resistance
Mg deficits/ inc urinary Mg excretion in people with insulin resistance. loss is secondary to inc glucose concentration in kidney that increases urine output. negative feedback cycle.
Mg adequacy –> low insulin secretion/ action –> worsening diabetes control.
