Effects of Estrogen and/or Progesterone on Morphology of Pituitary Luteinizing Hormone Cells

Objective To identify the morphological characteristics of pituitary luteinizing hormone (LH) cells after exogenous gonadal hormone treatment Methods Effects of various doses of estrogen, progesterone and their combination on morphological parameters, including the size and shape of pituitary LH cells, the size of endocellular vacuoles, were observed and measured by immuno histochemistry and computer image analysis. Results Different kinds of gonadal hormones could recover the magnified LH cells to the normal level in ovariectomized rats. However, their final effects on the gonadotrophin levels and the cellular morphological characters of the LH cells were different. The low dose of estrogen elicited abundant hormone stored in the LH cells to an easy released status with a lot of different size of vacuoles. On the contrary, the high dose of estrogen inhibited the storage of LH, and the LH cells were filled with secretory granules and few vacuoles. The progesterone could promote the storage of LH in an uneasy released status. The administration of estrogen progesterone combination not only inhibited the storage of LH, but also the release of LH. In this group, the LH cells containing a large amount of secretory granules and a few vacuoles showed a better uniform shape compared with those administrated with high dose of estrogen. Conclusion: Different kinds of gonadal hormones could reverse the excessive secretion of LH and recover the morphological change of LH cells to the normally physiological condition.