Studies In Vivo on the Effects of Parathyroid Hormone upon Kidney Cyclic Adenosine 3',5'-Monophosphate Content using Rapid Tissue Fixation by Microwave Irradiation

Nahorski, S. R.; Hunt, Nicholas H.; Rogers, Kathryn E.; Jones, Peter; Martin, T. J.

doi:10.1055/s-0028-1093623

Cited by 15 publications

(12 citation statements)

References 7 publications

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“…The effects of Gpp(NH)p and bPTH (2-34), together with the results of the radioimmunoassay studies, appeared to substantiate this. The clearest indication was that bPTH (2-34), which is thought to bind to bPTH receptors in chick kidney (Martin et al 1974;Hunt et al 1976;Nahorski et al 1976), could modify the effects of bPTH (Fig. 4, Tables 2 and 3) whereas oxidized bPTH (2-34) did not (Table 2).…”

Section: Pre-incubation Additionsmentioning

confidence: 93%

States of Activation of Chick Kidney Adenylate Cyclase Induced by Parathyroid Hormone and Guanyl Nucleotides

Michelangeli¹,

Hunt²,

Martin³

1977

Journal of Endocrinology

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Several aspects of the activation of adenylate cyclase by guanosine 5'-triphosphate (GTP), 5'-guanylylimidodiphosphate (Gpp(NH)p) and bovine parathyroid hormone (bPTH) have been studied in chick kidney plasma membrane preparations. GTP (10(-4) mol/l), Gpp(NH)p (10(-4) mol/l) and bPTH (10 i.u./ml) activated adenylate cyclase without any significant time lag. However a 2 min delay was observed before the activity of the enzyme increased after the addition of bPTH (-6 leads to +34) to incubations. The early (0-3 min) effects of GTP and Gpp(NH)p upon chick kidney adenylate cyclase activity were antagonized by the addition of the alternative guanyl nucleotide. After 5 min of incubation with kidney plasma membranes, Gpp(NH)p induced a stable state of activation of adenylate cyclase which was not reversible by subsequent addition of GTP. GTP did not induce an irreversible state of enzyme activation. In pre-incubation studies, GTP did not produce a persistent enzyme activation and did not modify the effect of Gpp(NH)p added subsequently at the incubation stage. Gpp(NH)p produced a stable state of activation of adenylate cyclase which was not inhibited by addition of GTP at the incubation stage. Bovine PTH (2-34) inhibited the effect of bPTH upon adenylate cyclase activity when the native hormone (10 i.u./ml) had been incubated with plasma membranes for up to 8 min before addition of the analogue (5 mug/ml). Incubation of plasma membranes with bPTH (2-34) for as little as 10 s prevented activation of adenylate cyclase by subsequent addition of bPTH. This pattern was confirmed in pre-incubation studies. After pre-incubation of kidney membranes with bPTH and bPTH (2-34), followed by washing, an acid extract of the membranes contained immunoreactive bPTH. Gpp(NH)p produced a greater increase in adenylate cyclase activity in membranes pre-incubated with bPTH or bPTH (2-34) than in membranes pre-incubated with buffer alone, suggesting that the hormone and analogue facilitated the interaction of Gpp(NH)p with adenylate cyclase.

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Section: Pre-incubation Additionsmentioning

confidence: 93%

States of Activation of Chick Kidney Adenylate Cyclase Induced by Parathyroid Hormone and Guanyl Nucleotides

Michelangeli¹,

Hunt²,

Martin³

1977

Journal of Endocrinology

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“…The cyclic AMP bioassay was modified as described by Zanelli et al (1986) from a method developed by Nahorski, Hunt, Rogers, Jones & Martin (1976). Male mice (18-25 g) of either NIH Statistical analysis Dose-response relationships were assessed using linear regressions of response on log dose.…”

Section: Cyclic Amp Bioassaymentioning

confidence: 99%

Effects of Peptides From the Calcitonin Genes on Bone and Bone Cells

Zaidi¹,

Bevis²,

Beacham³

et al. 1988

Exp Physiol

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SUMMARYThe calcitonin-calcitonin gene-related peptide (CGRP) gene complex encodes a family of novel peptides -calcitonin, CGRP and katacalcin. Whereas calcitonin is a circulating hormone involved in skeletal maintenance, the physiological function of CGRP still remains unclear. In the present study we have compared the biological activity of CGRP with that of calcitonin using three experimental systems. We have demonstrated that both peptides inhibit bone resorption by active rat osteoclasts and thus lower plasma calcium when injected into young rats. In both respects the CGRP homologues (rat, human a and human /) were found to be 100-to 1000-fold less potent than human calcitonin. The effects of the CGRP peptides and calcitonin were only additive. Human CGRP (ac) also caused a marked dose-dependent elevation of bone cyclic AMP levels in mice, somewhat like calcitonin. Though from our studies it would seem reasonably clear that CGRP is weakly agonistic for the calcitonin receptor on the osteoclast to produce effects on bone resorption and plasma calcium, it is still unclear whether the elevation of bone cyclic AMP simply represents an osteoclastic effect or an additional, more important, effect on osteoblasts. It is highly unlikely that CGRP may exert systemic effects on bone. Nevertheless, the peptide may be an important local regulator of bone cell function.

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“…1 g wt) were taken from both lobules and treated with microwaves (40 s at 350 W) in a domestic microwave oven to fix tissue cyclic AMP (Nahorski, Hunt, Rogers, Jones & Martin, 1976). Samples were then immediately homogenized in 4 ml ice-cold phosphate buffer containing 100 pM-IBMX to prevent cyclic AMP breakdown by tissue phosphodiesterase.…”

Section: Methodsmentioning

confidence: 99%

Parathyroid hormone‐(1–34) peptide activates cyclic adenosine 3',5'‐monophosphate in the human placenta

Williams

Abramovich²,

Cg³

et al. 1991

Experimental Physiology

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SUMMARYDually perfused human term placental lobules were exposed to forskolin, bovine parathyroid hormone (bPTH(1-34)) and human parathyroid hormone related-peptides, hPTHrP(1-34), hPTHrP(67-86)NH2 or PTHrP(107-138) for 15 min in the presence of 3-iso-butyl-1-methylxanthine (IBMX); control lobules were exposed to IBMX alone. Homogenates of these tissues were then assayed for cyclic adenosine 3',5'-monophosphate (cyclic AMP) and results normalized per mg of protein. Exposure to forskolin or bPTH(1-34) on both sides, and exposure to bPTH(1-34) at a concentration of 30 nm on the maternal side of the placenta or 120 nm on the fetal side of the placenta, significantly enhanced tissue cyclic AMP production compared with tissue exposed to IBMX alone. Exposure to hPTHrP(1-34), hPTHrP(67-86)NH2 and hPTHrP(107-138) at a concentration of 30 nm on both sides of the placenta had no significant effect upon tissue cyclic AMP production.

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Studies In Vivo on the Effects of Parathyroid Hormone upon Kidney Cyclic Adenosine 3',5'-Monophosphate Content using Rapid Tissue Fixation by Microwave Irradiation

Cited by 15 publications

References 7 publications

States of Activation of Chick Kidney Adenylate Cyclase Induced by Parathyroid Hormone and Guanyl Nucleotides

States of Activation of Chick Kidney Adenylate Cyclase Induced by Parathyroid Hormone and Guanyl Nucleotides

Effects of Peptides From the Calcitonin Genes on Bone and Bone Cells

Parathyroid hormone‐(1–34) peptide activates cyclic adenosine 3',5'‐monophosphate in the human placenta

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