A Preferential Binding Site for Insulin-Like Growth Factor II in Human andRat Placental Membranes*

Daughaday, William H.; Mariz, Ida K.; Trivedi, Bakula

doi:10.1210/jcem-53-2-282

Cited by 83 publications

(31 citation statements)

References 18 publications

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“…The equilibrium affinity constants for [1251]-insulin binding fall in the range of previously reported values for insulin binding to term placental membranes (25,36,43), Triton-X solubilized term placental receptors (26), and term placental syncytiotrophoblast microvillus membrane vesicles (51,59). The equilibrium affinity constants for [1251]-ILAs binding to midterm and term tissue are in agreement with our own previous term placental studies (46) and are almost identical to those of Daughaday et al (13) for IGF-I1 binding to term placental tissue. This is not surprising in view of the marked similarities between ILAs and IGF-I1 (23).…”

Section: Discussionsupporting

confidence: 90%

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Ontogeny of Growth Factor Receptors in the Human Placenta

et al. 1982

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Section: Discussionsupporting

confidence: 90%

“…This is not surprising in view of the marked similarities between ILAs and IGF-I1 (23). It should be noted that human placental membrane binding of all of the IGFs tested to date generates curvilinear Scatchard plots (7,13,24,46,57), suggestive of receptor heterogeneity.…”

Section: Discussionmentioning

confidence: 98%

Ontogeny of Growth Factor Receptors in the Human Placenta

et al. 1982

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“…Once it was possible to measure IGF-II levels in human plasma specifically, these were found to be remarkably high and constant throughout life from shortly after birth, and but mildly influenced by GH or nutritional status [239, 253, 254, 255]. Obviously, the constancy of plasma levels does not reflect a similar stability at the tissue level.…”

Section: Sf As Endocrine Substancementioning

confidence: 99%

A Personal View on the Early History of the Insulin-Like Growth Factors

Brande¹

1999

Horm Res Paediatr

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Salmon and Daughaday, when trying to set up an in vitro assay for Growth Hormone (GH), failed to obtain a direct effect on sulphate uptake in cartilage of hypophysectomized (hypox) rats. They recognised that this was not the consequence of poor methodology or materials, but an encrypted message from the examined system. They decided to turn around and to try and decipher it. Treatment with GH appeared to render hypox rat serum active in stimulating sulphation in hypox rat cartilage. They proposed that GH induced an intermediary substance, responsible for this biological effect: sulphation factor (SF), later renamed to Somatomedin(s) (SM). This hypothesis met with great criticism and very few took on to study this hypothetical substance. Besides disbelief, slow progress was also due to initial lack of a practical assay and to the failure to find a tissue with enriched concentration from which to extract the activity. From experimental evidence, the concept gradually evolved that SF/SM was insulin-like and might be identical to NSILA (non-suppressible insulin-like activity). This again generated controversy. This characteristic was too far away from the known effects of GH to be readily acceptable as a physiological phenomenon. The subsequent recognition of the distinct characteristics of the receptors for SM/NSILA and insulin, the discovery of the SM/NSILA binding proteins and, much later, a beginning understanding of their interactions, modifications and breakdown, have gradually resolved this apparent contradiction. When the sequence of two NSILA molecules became known, they were named IGF-I and -II. Structural similarity with proinsulin and identity of IGF-I with SM-C and -A were established and it was found that Multiplication Stimulating Activity (MSA), a growth factor isolated from fetal calf serum and subsequently from conditioned media of a rat liver cell line, was the rat equivalent of IGF-II. Structure-function relations could be studied, a quest which is not yet brought to an end. Meanwhile, the endocrine profile of SF/SM had gradually emerged by measuring plasma levels with bioassays. The main determinants were found to be age, body size, GH and the nutritional state. Later, radioimmunoassays were developed, enabling consolidation and detailing of these early observations, and allowing explorations at the tissue level. As another aspect of the endocrine paradigm, in vivo effects of IGFs were studied. The initial demonstration of an effect of crude preparations on longitudinal growth in experimental animals raised heavy scepticism, since the effect might have been an artefact caused by contaminants. It took confirmation with highly purified preparations and biosynthetic IGF-I to ease this concern. Still, not until recent years it was demonstrated, by knocking out the genes, that a true physiological and not a pharmacological effect had been induced previously.When it was found that most tissues produce SMs and are sensitive to their actions, the concept emerged that IGFs may have para- and autocrine fu...

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“…Using different 125I-labeled IGFs as radioligands, we have distinguished different types of IGF receptors (10)(11)(12). Although IGF receptors generally recognize both IGF-I-like and IGF-II-like peptides, receptors in different tissues and even in the same tissue can be distinguished by differences in their affinity.for.IGF-I and IGF-II and by their reactivity with insulin (10)(11)(12)(13). This difference in binding specificity appears to correlate with the subunit structure ofthe IGF receptors (14).…”

mentioning

confidence: 99%

Structure of the insulin-like growth factor receptor in chicken embryo fibroblasts.

Kasuga¹,

Obberghen²,

Nissley³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

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The insulin-like growth factors (IGFs) and insulin stimulate DNA synthesis and cell multiplication in chicken embryo fibroblasts in culture. This response appears to be mediated by interaction with a single type of IGF receptor. The present study examines the subunit structure ofthis receptor by covalently crosslinking two "MI-labeled IGFs, IGF-I and multiplication-stimulating activity (MSA), to chicken embryo fibroblasts by using disuccinimidyl suberate. After solubilization, NaDodSO4polyacryl-amide gel electrophoresis, and autoradiography, IGF receptor complexes of appropriate specificity were identified; they had Mr :130,000 (major band) and -260,000 (minor band) under reducing conditions and Mr >300,000 without disulfide reduction. The proportion ofthe Mr 260,000 component increased-with increasing concentration of crosslinking agent, suggesting that it was formed from smaller proteins during the crosslinking procedure. The IGF receptor in chicken embryo fibroblasts resembles the insulin receptor in size and structure but can be. distinguished by a higher affinity for IGF-I and MSA than for insulin. Although IGF receptors with different structure and specificity have been recognized in other tissues, the function of these binding sites is unknown. The present study demonstrates that the IGF receptor of chicken embryo fibroblasts that appears to mediate the growth-promoting

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A Preferential Binding Site for Insulin-Like Growth Factor II in Human andRat Placental Membranes*

Cited by 83 publications

References 18 publications

Ontogeny of Growth Factor Receptors in the Human Placenta

Ontogeny of Growth Factor Receptors in the Human Placenta

A Personal View on the Early History of the Insulin-Like Growth Factors

Structure of the insulin-like growth factor receptor in chicken embryo fibroblasts.

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