Affecting Calcium Homeostasis

How would a mutation that inactivates the parathyroid calcium receptor (CaR) affect calcium homeostasis ... 

Subcutaneous fat necrosis of the newborn is relatively uncommon. It is said to be benign and painless and to resolve within a few weeks. However, in this case it was extremely painful and was relieved only by opiates. The skin changes persisted beyond the age of 6 months and remained extremely symptomatic until the age of 9 months, when the skin had become normal. Calcium abnormahties have often been reported in association with subcutaneous fat necrosis, and exposure to amlodipine during pregnancy may have resulted in impairment of enzyme systems dependent on calcium fluxes for their action it may also have affected calcium homeostasis in the neonate. Since previous reports of teratogenicity in animals have been published, few women take calcium channel blockers during... 

Estrogens affect calcium homeostasis and have a beneficial effect on bone mass. They decrease bone resorption, and in prepubertal girls estrogen accelerates linear bone growth and results in epiphyseal closure.Long-term estrogen depletion is associated with loss of bone mineral content, an increase in stress fractures, and postmenopausal osteoporosis. ... 

Calcipotriol should not be used on the face or in skin folds because it may produce irritation due to increased absorption. Since vitamin D normally enhances calcium absorption from the intestines and its release from bone, hypercalcaemia is a potential side effect. However, only rarely is sufficient amounts of drug absorbed to affect calcium homeostasis in this way. 

Liantonio, A., V. Giannuzzi, V. Cippone, G. M. Camerino, S. Pierno, and D. C. Camerino. 2007. Fluvastatin and atorvastatin affect calcium homeostasis of rat skeletal muscle fibers in vivo and in vitro by impairing the sarcoplasmic reticulum/mitochondria Ca2-l-release system. Journal of Pharmacology and Experimental Therapeutics 321 626-634. 

Vitamin D is unique in that it can be either obtained from the diet (as vitamin D2 or D3) or synthesized from a cholesterol precursor, a process that requires reactions in the skin, liver, and intestine. The calciferols, including several forms of vitamin D, are a family of steroids that affect calcium homeostasis (Fig. 34.26). Cholecalciferol (vitamin D3) requires ultraviolet light for its production from 7-dehydrocholesterol present in cutaneous tissues (skin) in animals and from ergosterol in plants. This irradiation cleaves the carbon-carbon bond at C9-C10 to open the B ring to form cholecalciferol, an inactive precursor of l,25-(OH)2-cholecalciferol (calcitriol). Calcitriol is the most potent biologically active form of vitamin D (see Fig. 34.26). 

Due to the report by Manalis and Cooper in 1973 that lead inhibits calcium-triggered release of neurotransmitters (452), much attention has focused on the possibility that lead interacts with calcium proteins and/or affects calcium homeostasis (40, 173, 338-340, 351, 355, 443, 453 64). Indeed, patch clamp studies reveal that lead blocks voltage-dependent calcium channels (459, 464, 465), but the effects are highly dependent on the channel and cell type (460). In addition, lead has been shown to stimulate efflux from nerve cells via Ca -ATPase in a calmodulin-dependent fashion, resulting in a net decrease in... 

Insecticides Affecting Calcium Homeostasis - Flubendiamide Table 31.3 Toxicity of flubendiamide to natural enemies [8]. 

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