Do gonadotropes bind the releasing hormone that stimulates Growth hormone cells, during the period of transition?
(Growth hormone releasing hormone) If the GH cells retain their ability to bind GHRH (their normal phenotype), then we should be able to use dual labeling affinity cytochemistry to detect biotinylated GHRH and either LH or FSH antigens in the transitional “somatogonadotropes”. This binding should be highest during proestrus, when the GH cells express LH and FSH mRNAs. As will be presented at the upcoming meetings of the Endocrine Society (June, 1998), proestrous female rats have significant numbers of gonadotropes (70-80%) that bind GHRH compared with 20-30% of gonadotropes from male rats. This transitional expression correlates well with the hypothesis that growth hormone cells contribute to the gonadotrope population, but appear to retain their GH phenotype. (click here to see a copy of the abstract) The photograph below shows dual labeling for biotinylated GHRH (Bio-GHRH; seen as dense purple-black, arrows) and LH (orange) in gonadotropes from proestrous female rats. Note that the l
