Activation of avian medullary bone osteoclasts by oxidized synthetic parathyroid hormone (1-34).
Synthetic bovine parathyroid hormone (1-34) [bPTH(1-34)] has been treated with hydrogen peroxide and assayed for the effect of such treatment on the ability of bPTH(1-34) to activate medullary bone osteoclasts during their quiescent period in the early phase of the ovulatory cycle in Japanese quail. In addition, the same batches of oxidized and unoxidized bPTH(1-34) were assayed for their hypercalcemic activity in Japanese quail and their capacity to stimulate renal adenylate cyclase activity in the same species. Three groups, each consisting of five 5-month-old egg-laying Japanese quail (Coturnix coturnix japonica), were used. Between 4 to 5 hr after oviposition the three groups were injected intraperitoneally with acid saline (control) solution, bPTH(1-34) at 40 micrograms/bird, or oxidized bPTH(1-34) at 40 micrograms/bird, respectively. Twenty minutes after injection, the femoral bones were removed, split, fixed, and appropriately processed for examination by electron microscopy. Both oxidized and unoxidized bPTH(1-34) stimulated the development of osteoclast ruffled borders within 20 min after injection of the hormone preparations. As anticipated from previously published work from this laboratory, oxidized bPTH(1-34) retained its hypercalcemic activity and lost its capacity to stimulate renal adenylate cyclase activity in the Japanese quail. These results support, but do not prove, the contention that bPTH(1-34) exhibits its responses in the Japanese quail through the mediation of more than one type of receptor.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000097:blood; D003370:Coturnix; D005260:Female; D006861:Hydrogen Peroxide; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D008297:Male; D010010:Osteoclasts / Q000187:drug effects* / Q000648:ultrastructure; D010058:Oviposition; D010084:Oxidation-Reduction; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*
D010281:Parathyroid Hormone; D010446:Peptide Fragments; C025076:parathyroid hormone (1-34), bovine; D006861:Hydrogen Peroxide; D000262:Adenylyl Cyclases; D002118:Calcium