Post-transcriptional regulation of bovine parathyroid hormone synthesis.
Incubation of bovine parathyroid cells for 48 h in 0.4 mmol calcium/l had no significant effect on steady-state preproparathyroid hormone (preproPTH) mRNA levels when compared with cells incubated in 1.0 mmol calcium/l, but low calcium concentrations increased the membrane-bound polysomal content of preproPTH mRNA by 200 +/- 16% (mean +/- S.D.). No preproPTH mRNA was detected on free polysomes. Actinomycin D (5 and 10 micrograms/ml) had no effect on steady-state preproPTH mRNA levels measured in dot-blot assays after 24 h, but reduced levels in cells incubated in 1.0 mmol calcium/l to 54 +/- 16% and 39 +/- 12% of control values respectively after 48 h of incubation. Similarly, in cells incubated in 0.4 mmol calcium/l, actinomycin D (5 and 10 micrograms/ml) reduced steady-state preproPTH mRNA levels to 57 +/- 13% and 45 +/- 5% of control values respectively. Actinomycin D did not prevent the rise in polysomal content of preproPTH mRNA induced in cells by incubation in 0.4 mmol calcium/l, but increased polysomal content in cells incubated in 0.4 and 1.0 mmol calcium/l by 159 +/- 9% and 164 +/- 13% respectively after 48 h. These results demonstrate post-transcriptional regulation of PTH synthesis in cultured bovine parathyroid cells, and suggest that this control involves a protein which may be calcium-sensitive.
Hawa
N S
NS
Department of Medicine, University College, London, UK.
O'Riordan
J L
JL
Farrow
S M
SM
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D046508:Culture Techniques; D003609:Dactinomycin / Q000494:pharmacology; D010280:Parathyroid Glands / Q000187:drug effects / Q000378:metabolism; D010281:Parathyroid Hormone / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D010281:Parathyroid Hormone; D011498:Protein Precursors; D012333:RNA, Messenger; D003609:Dactinomycin; C019056:preproparathormone; D002118:Calcium