DISTRIBUTION OF ALPHA-SUBUNITS AND BETA-SUBUNITS OF GLYCOPROTEIN HORMONES IN THYROGONADOTROPH IN THE ANTERIOR-PITUITARY-CELLS OF THE MUSK SHREW (SUNCUS-MURINUS)

In order to examine the distribution pattern of alpha- and beta-subuni ts of glycoprotein hormones in small and large granules in the thyrogo nadotrophs of the musk shrew, we used an antiserum against a synthesiz ed peptide consisting of the sequence 37-53 of the rat alpha-subunit, which is highly conservative among several mammalian species, and also antisera to LH beta, FSH beta and TSH beta. Both alpha- and LH beta-s ubunits were colocalized in what appeared at the light-microscopic lev el to be the same cells, and the population ratio of alpha- and LH bet a-subunit immunoreactive cells was almost equal within each group of a nimals. In addition, we also demonstrated thyrogonadotrophs in the inf ant musk shrew as well as in the adult. Concerning small and large gra nules in thyrogonadotrophs of the musk shrew, we could observe small g ranules immunoreactive for only the alpha-subunit, for the LH beta-sub unit and for both the alpha- and LH beta-subunits; while only the LH b eta-subunit was observed in the large granules and the alpha-subunit w as absent. Consequently, we propose that the large granules observed i n the thyrogonadotrophs of the musk shrew may be storage sites for bet a-subunits and are not secretory-type granules.