Calcitonin, effect metabolism

FIGURE 5.4 Microphysiometry responses of HEK 293 cells transfected with human calcitonin receptor, (a) Use of microphysiometry to detect receptor expression. Before transfection with human calcitonin receptor cDNA, HEK cells do not respond to human calcitonin. After transfection, calcitonin produces a metabolic response, thereby indicating successful membrane expression of receptors, (b) Cumulative concentration-response curve to human calcitonin shown in real time. Calcitonin added at the arrows in concentrations of 0.01, 0.1, 1.10, and lOOnM. Dose-response curve for the effects seen in panel B. 

FIGURE 11.3 One-way ANOVA (analysis of variance). One-way analysis of variance of basal rates of metabolism in melanophores (as measured by spontaneous dispersion of pigment due to G,.-protein activation) for four experiments. Cells were transiently transfected with cDNA for human calcitonin receptor (8 j-ig/ml) on four separate occasions to induce constitutive receptor activity. The means of the four basal readings for the cells for each experiment (see Table 11.4) are shown in the histogram (with standard errors). The one-way analysis of variance is used to determine whether there is a significant effect of test occasion (any one of the four experiments is different with respect to level of constitutive activity). 

Due to its anti-resorptive effects, calcitonin has been widely used to treat a variety of metabolic bone diseases, including osteoporosis. However, the availability of more potent drugs has lead to a decline in the clinical use of calcitonin. 

Nagata, N., Sasaki, M., Kinuira, N., Nakane, K. Effects of porcine calcitonin on the metabolism of calcium and cyclic AMP in rat skeletal tissue in vivo. Endocrinology 97, 527 (1975)... 

Know the effects of parathyroid hormone, calcitonin, and vitamin D in controlling calcium and phosphate metabolism. Know what controls the levels of such hormones in the bloodstream. 

Arzneimittel-Forsch. 31, 953 (1981). Metabolism and disposition in rats K. Yoshida el aL. Radioisotopes 34, 612. 618 (1985). Effect in rats on estrogen-stimulated Calcitonin secretion 1. Yamazaki, Life Sci. 38, 757 (1986) I. Yamazaki. M. Kinoshita, ibid. 1535 on glucocorticoid-induced osteoporosis . Yamazaki el al. ibid. 951. 

The thyroid secretes two types of hormones iodine-containing amino acids (thyroxine and triiodothyronine) and a peptide (calcitonin). Thyroxine and triiodothyronine have very general effects on growth, development, and metabolism. Calcitonin is important in calcium metabolism and is discussed in Chapter 41. This chapter describes the drugs used in the treatment of hypothyroidism and hyperthyroidism (Figure 38-1). 

Figure 42-2. Some effects of vitamin D (D), parathyroid hormone (PTH), and calcitonin (CT) on calcium and phosphorus metabolism. Vitamin D increases absorption of calcium from both gut and bone, while PTH increases reabsorption from bone. Both vitamin D and parathyroid hormone reduce urinary excretion ot calcium. (Reproduced, with permission, from Katzung BG [editor] Basic Clinical Pharmacology, 8th ed. McGraw-Hill, 2001.)...

Nevertheless, claims of partial purification of the natriuretic hormone are not definitive. Moreover, well-known hormones, such as calcitonin and a-NSH, could also be responsible for the natriuretic effect. It is questionable that either of these hormones plays a considerable role in regulating sodium metabolism. Hormone responses to sodium loads and losses are summarized in Fig. 9-9, and the hypothetical role of the natriuretic hormone is illustrated in Fig. 9-10. 

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