Characterization of a Protein in Mid-Term Human Amniotic Fluid which Reacts in the Somatomedin-C Radioreceptor Assay*

Chochinov, Ronald H.; Mariz, Ida K.; Hajek, Anthony S.; Daughaday, William H.

doi:10.1210/jcem-44-5-902

Cited by 104 publications

(38 citation statements)

References 13 publications

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“…It has been suggested that IGFs stimulate follicular growth, dif ferentiation and steroidogenesis. IGF-1 has been reported to stimulate aromatase mRNA levels and P450arom activi ty in cultured human granulosa-luteal cells [20], A family of binding proteins (IGFBP-1-6) which binds with both IGF-I and II with high affinity has been reported to be present in serum [10], amniotic fluid [5,6], other body fluids [7][8][9]11], and in the conditioning medium from several cultured cell lines [21]. It has been suggested that the IGFBPs modulate the availability of the IGF to their target cells, and play an important role in the regulation of autocrine or paracrine action of IGF.…”

Section: Discussionmentioning

confidence: 99%

Insulin-Like Growth Factor-Binding Protein-1 in Human Follicular Fluid: A Marker for Oocyte Maturation

Kawano¹,

Narahara²,

Matsui³

et al. 1997

Gynecol Obstet Invest

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In order to investigate the role of insulin-like growth factors (IGFs) in human ovulation, we evaluated the concentrations of IGF-binding proteins (IGFBPs) in human follicular fluid (FF). The concentrations of IGFBP-1 in the FFs of 15 women undergoing in vitro fertilization and embryo transfer were measured and related to those of 17Β-estradiol (E₂), progesterone and androstenedione in the FFs. IGFBP-1 levels in the FFs were positively correlated with those of E₂ and progesterone. No correlation was found between the IGFBP-1 and androstenedione levels in FFs. The concentrations of IGFBP-1 were significantly increased in the FFs which contained mature oocytes compared with those of immature oocytes, whereas IGFBP-3 in FFs tended to decrease as oocytes matured. It is suggested that IGFs may play important roles in human preovulatory processes, and that IGFBP-1 may be a valuable biochemical marker in the evaluation of oocytes.

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Section: Discussionmentioning

confidence: 99%

Insulin-Like Growth Factor-Binding Protein-1 in Human Follicular Fluid: A Marker for Oocyte Maturation

Kawano¹,

Narahara²,

Matsui³

et al. 1997

Gynecol Obstet Invest

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“…The first IGF-BP (BP1) was isolated independently by Chochinov et al [121]and Drop et al [122]from amniotic fluid. IGF-BP-1 was later shown by Suikkari et al [123]and others to be regulated directly by insulin, explaining its acute changes with nutrition and its opposite changes with the GH-status.…”

Section: Sulphation Factor-somatomedin Is Insulin-likementioning

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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“…Term placental ILAs (22) and MSA (7) cytosolic binding proteins have previously been characterized, but i t is not known whether the midterm binding activity detected in this study corresponds to these molecules. The high level of ILAs specific binding in midterm cytosol is of interest in view of the increase in IGF binding proteins in midterm amniotic fluid (10,18). Thus our results raise the question of whether the large molecular weight placental cytosol binding proteins (estimated molecular weight 60,000 daltons) subserve a precursor function for the smaller IGF binding proteins (estimated molecular weight 34,500 daltons) in amniotic fluid.…”

Section: Discussionmentioning

confidence: 68%