Properties of hepatic binding sites for prolactin in ring doves (Streptopelia risoria)

Buntin, John D.; Keskey, Thomas; Janik, Daniel S.

doi:10.1016/0016-6480(84)90013-3

Cited by 20 publications

(9 citation statements)

References 30 publications

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“…In contrast, this same preparation was 15 times less effective than oPRL in competing with 125I-labelled oPRL in binding to dove forebrain mem¬ branes (Buntin & Ruzycki, 1987). Similar results were obtained with a different preparation of tPRL in com¬ petitive binding studies with 125I-labelled oPRL in dove liver membranes (Buntin et al 1984). Whilst the potency of tPRL in suppressing LH secretion cannot be accurately determined without dose-response data, our findings suggest that the difference in potency between oPRL and tPRL is less than that which would be expected from competitive binding studies with these preparations.…”

Section: Discussionsupporting

confidence: 78%

“…injection, the degree to which the effects of these hor¬ mones vary qualitatively or quantitatively with the route of hormone administration has not been ade¬ quately clarified. Reductions in circulating levels of LH (R. W. Lea, unpublished data) and testicular weights (Buntin et al 1984) are also observed in doves given systemic injections of oPRL. However, doses approximating three orders of magnitude greater than those used in the present study are required for these responses.…”

Section: Discussionmentioning

confidence: 66%

“…Because hGH binds to GH receptors as well as to prolactin receptors in a variety of target tissues (Nicoli, White & Leung, 1980;Nicoli, Tarpey, Mayer & Russell, 1986) and has been shown to com¬ pete effectively with 125I-labelled oPRL for binding to dove forebrain membranes (Buntin & Ruzycki, 1987), the suppressive actions of hGH on LH secretion could be explained by its prolactin-like activity. In contrast, oGH and tGH are poor competitors of oPRL in bind¬ ing to prolactin receptors in dove brain (Buntin & Ruzycki, 1987) and dove liver (Buntin, Keskey & Janik, 1984), with average relative binding potencies ranging from <0T to 2% ofoPRL in these two tissues. Moreover, the degree of contamination of the oGH preparation with prolactin and other anterior pituitary hormones is estimated by the NIADDK at 2% or less.…”

Section: Discussionmentioning

confidence: 81%

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Reductions in plasma LH concentration and testicular weight in ring doves following intracranial injection of prolactin or growth hormone

Buntin

Lea²,

Figge³

1988

Journal of Endocrinology

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Testicular weights and concentrations of LH in plasma were measured in individually housed adult male ring doves given five daily intracerebroventricular injections of saline-NaHCO3 vehicle (2 microliter), ovine prolactin (0.1, 0.5, 1.0 or 2.0 micrograms/day), turkey prolactin (1.0 micrograms/day), turkey GH (1.0 micrograms/day) or ovine GH (1.0 micrograms/day). Administration of ovine prolactin resulted in a dose-dependent suppression of plasma LH concentration, with values in the two highest dose groups averaging three- to fivefold less than those of vehicle-injected controls. Reductions of similar magnitude were obtained following intracranial administration of turkey, ovine or human GH. Whilst effective in reducing plasma LH, turkey prolactin was less effective than an equivalent dose of ovine prolactin. Testicular regression was observed in all treatment groups which showed a significant decrease in plasma LH concentrations. Because crop sacs remained undeveloped in all treatment groups, it was concluded that these centrally administered hormones acted primarily at the level of the brain or pituitary to exert their suppressive effects. The possibility that prolactin and GH interact with different binding sites to inhibit LH secretion is discussed, together with evidence for a possible role of prolactin and GH in gonadotrophin regulation under normal physiological conditions.

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Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 81%

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Reductions in plasma LH concentration and testicular weight in ring doves following intracranial injection of prolactin or growth hormone

Buntin

Lea²,

Figge³

1988

Journal of Endocrinology

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“…Bates, Miller & Garrison, 1962;Goodridge & Ball, 1967a;Nicoli, 1967) and from recent demonstrations that both tissues possess specific, saturable binding sites for prolactin (Kledzik, Marshall, Gelato et al 1975;Forsyth, Buntin & Nicoli, 1978;Buntin, Keskey & Janik, 1984). A strong dose-dependent effect of prolactin injections on body weight change was also observed.…”

Section: Discussionmentioning

confidence: 58%

“…Alternatively, males and females may differ in target tissue responsiveness to prolactin. Buntin et al (1984) have shown that a crude membrane fraction from pooled liver homogenates of male doves during incubation shows higher specific binding to ovine prolactin than pooled membranes from female doves and that this difference reflects a change in binding capacity. A similar mechanism may underlie the differential sensitivity to prolactin observed between the sexes in other target organs.…”

Section: Discussionmentioning

confidence: 97%

Behavioural and physiological effects of prolactin in incubating ring doves

Janik¹,

Buntin²

1985

Journal of Endocrinology

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The role of prolactin in the maintenance of incubation behaviour in ring doves was re-examined and the dose-response relationships for behavioural, target tissue and body weight changes induced by injections of prolactin were compared in doves tested during the incubation phase of the breeding cycle. Doves given injections of prolactin twice a day starting on day 4 of incubation, during a 10-day period of isolation from their mates and nests, showed a higher persistence of incubation behaviour than doves injected with saline vehicle. However, the prolactin treatment failed to maintain incubation behaviour to the same extent as that observed in non-isolated untreated breeding pairs. Liver and body weights were higher and testicular weights lower in birds treated with high doses of prolactin than in non-isolated birds which had been incubating for 14 days. Good dose-response relationships were established between body, liver, crop and testes weights and the dose of prolactin administered. However, only a weak dose-response relationship was observed between prolactin and the maintenance of incubation behaviour. Overall, females injected with prolactin displayed more quiet sitting behaviour, less body weight gain and more gonadal regression than males injected with prolactin. Males in untreated breeding pairs had higher liver weights and lower crop weights than females. It is concluded that prolactin plays a role in maintaining readiness to incubate in doves, but that other factors may also contribute to this response. Further, it appears that prolactin mediates several target tissue changes which are sex-specific during incubation.

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Characterization of renal prolactin‐binding sites of two amphibians (Ambystoma tigrinum and Rana catesbeiana) and a reptile( Pseudemys scripta elegans)

Tarpey¹,

Nicoll²

1987

J. Exp. Zool.

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The specific binding of 125I-ovine prolactin (oPRL) to renal membrane preparations from Pseudemys scripta elegans, Ambystoma tigrinum, and Rana catesbeiana was characterized. All three membranes showed specific oPRL binding that was dependent upon time, temperature, pH, and membrane concentration. Scatchard analysis of the binding of 125I-oPRL revealed high-affinity sites with KA values of 2.1 X 10(10), 3.6 X 10(10), and 1.25 X 10(10) M-1 for kidney membranes of Pseudemys, Ambystoma, and Rana, respectively. In addition, there was a low-affinity site on the Ambystoma membranes. The binding capacities ranged from 31 to 70 fmol/mg of membrane protein. The hormonal specificity of these membranes was studied by competing increasing amounts of oPRL, human growth hormone (hGH) derived from recombinant DNA techniques, bovine (b) GH, and human placental lactogen (hPL) with 125I-oPRL. The oPRL standard and hGH were the most potent competitors in all three assays, although hGH was not as potent as the oPRL. Human PL was moderately active in the turtle kidney assay, weakly active in the Ambystoma radioreceptor assay, and inactive in the bullfrog assay. Bovine GH had low potency on the turtle membranes and was inactive in the amphibian assays. The results of these studies indicate that the characteristics of renal PRL receptors of Pseudemys, Ambystoma, and Rana are similar to those of lactogenic receptors throughout the vertebrates. In addition, these data provide evidence for the first time of renal PRL receptors in a reptile.

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Properties of hepatic binding sites for prolactin in ring doves (Streptopelia risoria)

Cited by 20 publications

References 30 publications

Reductions in plasma LH concentration and testicular weight in ring doves following intracranial injection of prolactin or growth hormone

Reductions in plasma LH concentration and testicular weight in ring doves following intracranial injection of prolactin or growth hormone

Behavioural and physiological effects of prolactin in incubating ring doves

Characterization of renal prolactin‐binding sites of two amphibians (Ambystoma tigrinum and Rana catesbeiana) and a reptile( Pseudemys scripta elegans)

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