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 “It’s the 3rd of July in 2001, and we are here at the 17th ESHRE Conference in Lausanne.  Next to me is Dr.       Clans Yding Andersen; he’s a researcher at the University of Copenhagen.  Good afternoon.”
       
       

 “I  want to talk with you about your presentation from yesterday, and I want  to have more of an explanation because it was a very difficult topic.   You talked about the role of FSH and especially the different isoforms  in the role in oocyte maturation.  Could you explain first these several  isoforms?”
       
       

   “Yes, FSH, as you may know, is a hormone which affects the ovary and can  make follicles grow and mature oocytes but it turns out that FSH, when  it’s released from the pituitary, can exist in several different forms.   It’s not the backbone of the molecule that’s altered, that’s similar  for all the different FSH isoforms but there is some sugar residue  sitting on it and they can change.  They can actually affect the  function of the molecule so it relates to the sugar residues which is  attached to the molecule.”
       
       

“And this means they all have a different action?”
       
       

  “It  actually may mean that they interact with the FSH receptor on the  follicles in a different way which we thought but just don’t quite know  at the present time how this interaction with the different FSH isoforms  actually occurs quite precisely.  There may be different ways that FSH  interacts with its receptor; it may give some responses in some  situations and other responses in other situations.”
       
       

 “That’s what you presented; you have a model to test these several ways of action?”
       
       

   “Yes, we have tried to use oocyte-cumulus complexes, the complex which  the oocyte - the egg - is sitting in when it’s released from the  follicle.  We tried to use that as a model to study the effect of the  different FSH isoforms and this actually may turn out to be quite a good  model to study this in because the cells which surround the egg and  which support the egg only have FSH receptors, they do not have LH  receptors.  They’re only affected by FSH and, furthermore, when the  oocytes - the egg - is taken out from the ovary it’s in the cycle when  there is a lot less acidic isoforms in circulation.  So it may well be  that the responses we obtained from this specific model is actually  reflecting quite well what happens in the body.”
       
       

 “Could you explain what the clinical implication of this research could be?”
       
       

  “If  we understand in more detail what the different FSH isoforms are  actually doing and we can apply that in a clinical situation then we may  actually be able to obtain eggs which upon fertilization in vitro or  for that matter in vivo have a higher developmental competence and are  more likely to generate embryos which will implant and can result in a  child.”
       
       

 “Can there also be a difference in the recombinant FSH and the purified FSH in terms of the isoforms?”
       
       

   “There is the recombinant FSH preparation, they have almost a similar  FSH iso-hormone profile but compared to the urinary derived  gonadotrophins they have a slightly more acidic isoform distribution  and, therefore, you may actually expect a higher biological in vivo  activity from the recombinant gonadotrophins.”
       
       

 “Which doesn’t appear in clinical practice.”
       
       

   “It’s a matter of how well the different gonadotrophin preparations will  affect oocyte maturation the way that their stimulation protocols are  done today because you use a large bolus of HGG to induce ovulation.  In  the final stages of oocyte maturation, actually, there may be a  beneficial role for FSH.  This is not used in the current day protocols  but if you include FSH and have a signal which induces ovulation and  final oocyte maturation, which resemble the mechanism that nature uses,  you may actually be able to obtain oocytes that have a better  competence.”
       
       

 “I  see but could this research also mean that you find a certain isoform of  FSH that’s more active than the recombinant FSH of nowadays that will  be a little change towards another isoform?”
       
       

   “Yes, I think maybe you could imagine that in the future you would use  different FSH isoforms in different parts of the cycle.  Maybe you would  start off by using more acidic isoforms and then as ovulation  approaches you would change to less acidic isoforms.  If you could also  use the less acidic isoforms in connection with a mid-cycle surge of  gonadotrophins then I imagine that you could actually obtain eggs which  were more competent and had a better maturation.”
       
       

  “Thank you very much, Dr.       Andersen.”

Articles

OBGYN.net Conference CoverageFrom the ESHRE 2001 Conference - Lausanne, Switzerland

The Role of FSH and Isoforms in Oocyte Maturation

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Author | Clans Andersen

Articles

The Role of FSH and Isoforms in Oocyte Maturation

The Role of FSH and Isoforms in Oocyte Maturation