Investigational anthrax vaccines
A number of experimental anthrax vaccines are undergoing pre-clinical testing, notably the Bacillus anthracis protective antigen—known as PA (see Anthrax toxin—combined with various adjuvants such as aluminum hydroxide (Alhydrogel), saponin QS-21, and monophosphoryl lipid A (MPL) in squalene/lecithin/Tween 80 emulsion (SLT). One dose of each formulation has provided significant protection (> 90%) against inhalational anthrax in rhesus macaques. Omer-2 trial: Beginning in 1998 and running for eight years, a secret Israeli project known as Omer-2 tested an Israeli investigational anthrax vaccine on 716 volunteers of the Israel Defense Forces. The vaccine—given under a seven-dose schedule—was developed by the Nes Tziona Biological Institute. A group of study volunteers complained of multi-symptom illnesses allegedly associated with the vaccine and petitioned for disability benefits to the Defense Ministry, but were denied. In February 2009, a petition from the volunteers to disclose a report about Omer-2 was filed with the Israels High Court against the Defense Ministry, the Israel Institute for Biological Research at Nes Tziona, the director, Avigdor Shafferman, and the IDF Medical Corps. Release of the information was requested to support further action to provide disability compensation for the volunteers. In 2014 it was announced that the Israeli government would pay $6 million compensation to the 716 soldiers who participated in the Omer-2 trial. In 2012, B. anthracis isolate H9401 was obtained from a Korean patient with gastrointestinal anthrax. The goal of the Republic of Korea is to use this strain as a challenge strain to develop a recombinant vaccine against anthrax.
The G-protein-coupled calcium receptors bind extracellular calcium and may be found on the surface on a wide variety of cells distributed in the brain, heart, skin, stomach, C cells, and other tissues. In the parathyroid gland, high concentrations of extracellular calcium result in activation of the Gq G-protein coupled cascade through the action of phospholipase C.  This hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to liberate intracellular messengers IP3 and diacylglycerol (DAG). Ultimately, these two messengers result in a release of calcium from intracellular stores into the cytoplasmic space. Hence a high extracellular calcium concentration leads to an increase in the cytoplasmic calcium concentration. In contrast to the mechanism that most secretory cells use, this high cytoplasmic calcium concentration inhibits the fusion of vesicles containing granules of preformed PTH with the membrane of the parathyroid cell, and thus inhibits release of PTH. In the parathyroids, magnesium serves this role in stimulus-secretion coupling. A mild decrease in serum magnesium levels stimulates the reabsorptive activity PTH has on the kidneys. Severe hypomagnesemia inhibits PTH secretion and also causes resistance to PTH, leading to a form of hypoparathyroidism that is reversible. Stimulators
Decreased serum [Ca2+]. Mild decreases in serum [Mg2+]. An increase in serum phosphate (increased phosphate causes it to complex with serum calcium,  forming calcium phosphate, which reduces stimulation of Ca-sensitive receptors (CaSr) that do not sense calcium phosphate, triggering an increase in PTH). Adrenaline
Histamine

Inhibitors
Increased serum [Ca2+]. Severe decreases in serum [Mg2+], which also produces symptoms of hypoparathyroidism (such as hypocalcemia). Calcitriol
Increase in serum phosphate.