EurekaMag.com logo
+ Translate

Regulation of lactogen specific binding sites in rat liver: studies on the role of lactogens and estrogen


, : Regulation of lactogen specific binding sites in rat liver: studies on the role of lactogens and estrogen. Endocrinology 99(5): 1168-1177

Regulation of the lactogen specific binding sites of rat liver was studied in several different high lactogen states. The specific binding of [125I]iodo-hGH was determined as a measure of these sites. Hypophysectomy of pregnant rats produced a much smaller decrease in hepatic binding of [125I]iodo-hGH than was seen in nonpregnant females. Three different prolactin secreting tumors (MtT/F4, MtT/F45, MtT/W5) produced greatly elevated levels of both rPRL and hepatic binding of [125I]iodo-hGH in both male and female rats. The increased binding reflected an increase in the concentration of lactogen specific membrane binding sites. There was no change in the apparent affinity of binding. Hypophysectomy of tumor-bearing rats was not followed by a decrease in the concentration of hepatic sites. Pituitary transplants beneath the kidney capsules of hypophysectomized (hypox) rats produced elevated rPRL levels and increased [125I]iod-GH specific binding to hepatic membranes. The elevation of serum rPRL preceded the increase in hepatic binding. There was a direct correlation between rPRL levels attained by 8 days after implantation and the level of hepatic binding. Estrogen treatment did not alter this correlation. Hormonal replacement with prolactin in combination with various hormones failed to induce the lactogen specific hepatic sites in estrogen treated hypox males, and did not prevent the marked decrease in hepatic binding observed in females following hypophysectomy. It is suggested that chronic elevation of prolactin plays a role in inducing lactogen specific binding sites in rat liver. Estrogen's inductive action seems to be largely effected at the pituitary level.

(PDF same-day service: $19.90)

Accession: 006288951

PMID: 186250

DOI: 10.1210/endo-99-5-1168

Submit PDF Full Text: Here


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Eriksson H.A., 1982: Estrogen binding sites of mammalian liver endocrine regulation of estrogen receptor synthesis in the regenerating rat liver. The influence of sex steroids on the synthesis of cytoplasmic estrogen receptors in fully differentiated and differentiating liver cells was studied under in vivo conditions. The liver of each animal in the study was analyzed with respect to total...

Smirnova, O.V.; Vishniakova, T.G.; Smirnov, A.N.; Rozen, V.B., 1985: Role of estrogens in the induction and regulation of a specific estrogen-binding protein in the rat liver. A study was made of the role of estrogens (E) in the induction and regulation of the level of specific estrogen binding protein (SEBP) in the rat liver using a differentiated quantitative method of its determination. It was shown that E could not...

Smirnova O.V.; Vishnyakova T.G.; Smirnov A.N.; Rozen V.B., 1985: The role of estrogens in the induction and regulation of the level of specific estrogen binding protein in the rat liver. A study was made of the role of estrogens (E) in the induction and regulation of the level of specific estrogen binding protein (SEBP) in the rat liver using a differentiated quantitative method of its determination. It was shown that E could not...

Gschwendt, M.; Kittstein, W., 1973: Specific estrogen binding sites on the liver chromatin of estrogen-pretreated roosters. Hoppe-Seyler's Zeitschrift für Physiologische Chemie 354(12): 1642-1644

Mochizuki, M.; Ueda, Y.; Tokiwa, Y.; Deguchi, M.; Morikawa, H., 1985: Studies on the ontogenesis and the regulatory mechanisms of placental lactogen and insulin binding sites (receptor) in rat liver. The ontogenesis of specific binding of 125I-hPL [human placental lactogen] and 125I-insulin was determined in rat liver cell membranes (105 .times. g pellets), and the regulatory mechanisms of these binding sites were also examined. There were str...

Harris G.S., 1970: Estrogen receptors studies on the nature of estrogen specific binding sites in the nuclei of immature mouse uteri. Journal Of Cell Biologypt 2: 83a

Smirnov, A.N.; Kondrat'ev, I.Iu.; Smirnova, O.V.; Rozen, V.B., 1978: Multicomponent system of specific estrogen-binding liver proteins. Some properties of a rapidly dissociating estrogen-binding liver protein from guinea pigs. A study was made of some binding and physico-chemical properties of a special estrogen-binding protein of liver cytozol in sexually mature female and male guinea pigs following its partial purification by means of ammonium sulfate sedimentation, g...

Smirnov, A.N.; Kondrat'ev-Ya-Yu ; Smirnova, O.V.; Rozen, V.B., 1978: Multi component system of specific estrogen binding proteins of the liver some properties of rapidly dissociating estrogen binding protein of the liver in guinea pigs. A study was made of some binding and physico-chemical properties of a special estrogen-binding protein of liver cytosol in sexually mature female and male guinea pigs following its partial purification by (NH4)2SO4 sedimentation, gel-filtration an...

Muldoon, T.G., 1971: Characterization of steroid-binding sites by affinity labeling. Further studies of the interaction between 4-mercuri-17-beta-estradiol and specific estrogen-binding proteins in the rat uterus. Biochemistry 10(20): 3780-3784

Vigneri, R.; Pezzino, V.; Cohen, D.; Pliam, N.B.; Wong, K.Y.; Hradek, G.; Jones, A.L.; Goldfine, I.D., 1980: Regulation of rat liver plasma membrane and intracellular insulin binding sites during diabetes, liver regeneration, and hyperinsulinism: radiolabeled hormone binding and electron microscopic autoradiograph studies. Advances in Biochemical Psychopharmacology 21: 499-506