Uptake of 125i-Labelled Prolactin by Rat Mammary Gland and Pigeon Crop Mucosa

Shani, J.; Givant, Y.; Sulman, F. G.; Eshkol, Aliza; Lunenfeld, Bruno

doi:10.1677/joe.0.0520397

Cited by 10 publications

(4 citation statements)

References 3 publications

(3 reference statements)

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“…Shani et al (1972) reported the uptake of 125I-labelled HCG by the pigeon crop sac mucosa and con¬ cluded that HCG binds to the same receptor as prolactin, but there was no evidence of this in the present study. Prolactin binding was dependent on the concentration of receptors, time and temperature but was not greatly affected by pH between 7 and 8.…”

Section: Discussioncontrasting

confidence: 77%

A Pigeon Crop Sac Radioreceptor Assay for Prolactin

Forsyth¹,

Buntin²,

Nicoll³

1978

Journal of Endocrinology

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Ovine prolactin, labelled with 125I by either lactoperoxidase or a mild chloramine T method, bound to receptors from the pigeon crop sac mucosa cells of prolactin-injected pigeons. Binding was demonstrated in a crude homogenate of mucosal cells removed from the crop by scraping and in a subcellular fraction in which 5'-nucleotidase activity was enhanced two- to threefold. The binding was specific, dependent on time, temperature and the concentration of receptors and had a dissociation constant of 7 X 10(-10) mol/l. The binding capacity of the crop tissue was 71 fmol/mg membrane protein. Nine purified preparations of prolactin from four species were assayed by local pigeon crop sac bioassay and by radioreceptor assay. The two methods were highly correlated (r = 0.934). The regression equation was radioreceptor assay = 1.22 bioassay--0.18 indicating a 1 : 1 correspondence between the two methods for prolactin purified from sheep, rat, horse and pig anterior pituitary glands.

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Section: Discussioncontrasting

confidence: 77%

A Pigeon Crop Sac Radioreceptor Assay for Prolactin

Forsyth¹,

Buntin²,

Nicoll³

1978

Journal of Endocrinology

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“…sac, which was suggested earlier by Shani, Givant, Sulman, Eshkol & Lunenfeld (1972) and Eshkol, Shani, Lunenfeld, Misgav & Sulman (1974).…”

supporting

confidence: 63%

Adenosine 3′:5′-Cyclic Monophosphate as a Possible Mediator in the Proliferative Effect of Prolactin on the Pigeon Crop Sac

Shani¹,

Sulimovici²,

Goldhaber³

et al. 1976

Journal of Endocrinology

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There is evidence that cyclic AMP mediates the secretion of adenohypophysial hormones induced by hypothalamic releasing hormones (Labrie, Pelletier, Lemay, Borgeat & Burden, 1973), that mammary gland explants respond to prolactin with increased levels of cyclic AMP (Scott & Howard, 1975), and that prolactin enhances adenyl cyclase activity when incubated with prostate homogenate (Golder, 1972). We therefore decided to examine the possible role of cyclic AMP in a local and highly specific effect: mediating stimulation of the pigeon crop sac by prolactin. Using this model it had already been demonstrated that ATP or GTP, but not cyclic AMP, potentiates the stimulatory effect of prolactin on proliferation of the pigeon crop sac (Sinha & Schmidt, 1970).Fifty adult male and female common pigeons (Columba livia domestica), weighing 500 ±50 g each, were housed in single cages and given access to grain and water ad libitum. Two weeks after capture the pigeons were divided into five groups, ten birds per group. Ovine prolactin N1H PS-9 (30-3 i.u./mg) was dissolved in minimal amounts of 0-1 M-NaOH, as suggested by NIAMDD, brought to a final volume of 0-4 ml/pigeon with 0-9% NaCl solution, and injected into four groups of pigeons in 0-1 ml amounts twice daily for 2 consecutive days.The total doses administered were 0 5, 0-1, 0-2 and 0-4 i.u./pigeon respectively. All solutions were injected intradermally over the right halves of the pigeon crop sac, while the left crophalves were injected with saline. The fifth group (controls) was injected with 0-002 M-NaOH solution, the recommended prolactin solvent. No side-effects (i.e. local inflammations) were recorded on any of the experimental pigeons. The pigeons were killed by decapitation, their crop-halves weighed, cut in small pieces, soaked in ice-cold Krebs-Ringer-bicarbonate buffer solution ( 7·4), 2-5 ml/g, and homogenized for 2 min. After adding trichloroacetic acid (TCA) to a final concentration of 5 %, the homogenates were centrifuged at 1000^for 20 min, 0-1 ml M-HC1 was added the the TCA extracted with diethyl ether. The residual ether was evaporated in a water bath at 55°C. Aliquots of this solution were evaporated to dryness with nitrogen, and cyclic AMP was determined according to the method of Gilman (1970), modified by using charcoal plus 2% bovine serum albumin to separate the bound from the free nucleo¬ tide as suggested by Brown (1971). The binding protein was prepared from rabbit muscle following the procedure of Miyamoto, Kuo & Greengard (1969). The recovery of cyclic AMP added to the tissue was 90 ± 7-2 %. Cyclic AMP values are expressed as pmol/g wet tissue.Ovine prolactin at each of the four doses which caused local proliferation of the crop mucosa markedly increased the cyclic AMP content of the treated crop-halves as compared with the saline-injected halves (Table 1). No difference in cyclic AMP concentration was observed between the two crop-halves of the control pigeons. These findings suggest that cyclic AMP may be a mediator in the proliferative effect...

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“…The cropsac prolactin receptor has been studied using binding assays (43, 70,109,110). Its cDNA was recently cloned.…”

Section: The Pigeon Prolactin Receptormentioning

confidence: 99%

Regulation of Pigeon Cropmilk Secretion and Parental Behaviors by Prolactin

Horseman¹,

Buntin²

1995

Annu. Rev. Nutr.

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Prolactin stimulates the growth and development of specialized epithelial cells lining the cropsac of pigeons and doves (family Columbidae), leading to formation of "cropmilk," which is fed to the newly hatched squab. This system of milk feeding is unique among birds. To support the feeding of cropmilk, a complex array of behavioral adaptations are also supported by high levels of prolactin secretion in columbids during parenting. These specializations include elevated food intake (hyperphagia), nest attendance, and regurgitation feeding of the squab. Although prolactin is clearly important for these behavioral adaptations, the precise physiological and mechanistic bases for these behavioral effects remain controversial. The molecular mechanisms of prolactin action in the cropsac epithelium have been studied by cloning prolactin-induced genes, by cloning and expressing the pigeon prolactin receptor, and by analyzing the transcription factors that are activated after prolactin treatment. The avian (pigeon) prolactin receptor is a member of the cytokine receptor superfamily and uniquely contains a complete duplication of the extracellular ligand-binding domain. One of the early signal-transducing actions of prolactin in cropsac epithelium is the activation of signal transducer and activator of transcription (STAT) proteins via tyrosine phosphorylation. This fundamental signaling pathway is shared with mammalian prolactin target tissues. The convergent evolution of milk feeding and the behaviors that support parenting in columbids and mammals has depended on adaptation of both conserved mechanisms and divergent physiological processes.

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Uptake of 125i-Labelled Prolactin by Rat Mammary Gland and Pigeon Crop Mucosa

Cited by 10 publications

References 3 publications

A Pigeon Crop Sac Radioreceptor Assay for Prolactin

A Pigeon Crop Sac Radioreceptor Assay for Prolactin

Adenosine 3′:5′-Cyclic Monophosphate as a Possible Mediator in the Proliferative Effect of Prolactin on the Pigeon Crop Sac

Regulation of Pigeon Cropmilk Secretion and Parental Behaviors by Prolactin

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