Effects of YM175, a new-generation bisphosphonate, on hypercalcemia induced by tumor-derived bone resorbing factors in rats.
YM175 (disodium cycloheptylaminomethylenediphosphonate monohydrate) is a new-generation bisphosphonate with stronger inhibitory activity on bone resorption than first-generation bisphosphonates. In the present study, the effect of YM175 on hypercalcemia induced in rats by single administration of either parathyroid hormone-related protein (PTHrP) or concomitant administration of PTHrP and interleukin 1beta (IL-1beta) was investigated. YM175 (0.01-1 mg/kg, i.v.) inhibited the increase in serum free calcium concentration induced by continuous administration of PTHrP alone (3 microg/rat/day, s.c., 7 days) dose-dependently. The inhibitory effect of YM175 appeared the day after administration and remained 3 days after administration. The effect of YM175 reached a maximum 2 days after administration, at which time the ED50 value of YM175 was calculated to be 0.041 mg/kg, i.v., revealing a potency approximately 50- and 10-fold stronger than those of either pamidronate or alendronate, respectively. In contrast, elcatonin (1-10 units/kg, s.c.) only transiently inhibited PTHrP-induced free calcium increase. YM175 (0.1-3 mg/kg, i.v.) also inhibited the increase in the serum free calcium concentration induced by continuous concomitant administration of both PTHrP and IL-1beta in a dose-dependent manner. These results indicated that YM175 is expected to be a useful drug for hypercalcemia associated with malignant tumors due to its efficacy and range of effect.
Takahashi
K
K
Pharmacology Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tokyo, Japan.
Shirahata
A
A
Fukushima
S
S
Kokubo
S
S
Teramura
K
K
Usuda
S
S
D000818:Animals; D001862:Bone Resorption / Q000517:prevention & control*; D004164:Diphosphonates / Q000627:therapeutic use*; D006934:Hypercalcemia / Q000150:complications / Q000188:drug therapy*; D007375:Interleukin-1 / Q000008:administration & dosage; D008297:Male; D008954:Models, Biological; D009374:Neoplasms, Experimental / Q000150:complications; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar
D004164:Diphosphonates; D007375:Interleukin-1; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; C071542:cimadronate