Effects of parathyroid hormone on cyclic-AMP concentrations of in vitro Necturus maculosus gastric antrum.
The effects of bovine parathyroid hormone (bPTH1-84) on the stimulation of intracellular cyclic-AMP [cAMP] were investigated in an in vitro preparation of Necturus maculosus antral mucosa. When the antrum was exposed to 1, 5, 10, or 100 nM bPTH1-84, there was an approximately 2-fold nonlinear increase in tissue [cAMP] over basal values. The pretreatment of the antral mucosa with 1 mM isobutylmethylxanthine (IBMX, a phosphodiesterase inhibitor) increased with detectability of mucosal [cAMP]. The addition of 1, 5, 10, or 100 nM bPTH1-84 to tissues pretreated with IBMX resulted in an approximately 3.5-fold linear increase in mucosal [cAMP] over basal values. The time course of the generation of mucosal cAMP to 10 nM bPTH1-84 resulted in a small but significant transient increase at 2.5 min after the addition of bPTH1-84 but no change in the medium [cAMP]. In tissues pretreated with 1 mM IBMX the response to 10 nM bPTH1-84 was a large biphasic increase of [cAMP] at 2.5 min that progressively declined to near basal values by 15 min. There was also a significant sustained increase in the [cAMP] in the bathing medium at 2.5 min of tissues pretreated with IBMX followed by 10 nM bPTH1-84. These results suggest the presence of an adenylate cyclase that can be activated by a mammalian bPTH1-84 in elevating intracellular cAMP levels in the N. maculosus antral mucosa.
Rutten
M J
MJ
Veterans Administration Hospital Medical Center, Medical Research Service, Kansas City, Missouri 64128.
Chern
H T
HT
Moore
C D
CD
Hamilton
J
J
Cheung
L Y
LY
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects / Q000502:physiology; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009338:Necturus maculosus; D010281:Parathyroid Hormone / Q000502:physiology*; D011706:Pyloric Antrum / Q000378:metabolism*
D010281:Parathyroid Hormone; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine