FINE STRUCTURE OF CORPORA LUTEA IN OVARIAN TRANSPLANTS OF MICE FOLLOWING LUTEOTROPHIN STIMULATION

Lutein cells from non‐functional white corpora lutea of ovulation and functional hyperemic corpora following exogenous luteotrophin stimulation were studied in ovarian isotransplants of the mouse with the aid of the light and electron microscope. Luteal tissue of white corpora consisted of small parenchymal cells, some intercellular material and a meager vascular bed. Luteal tissue from hyperemic corpora lutea possessed a rich sinusoidal plexus which supplied the hypertrophied lutein cells. At the fine structural level, lutein cells from functional, hyperemic corpora were distinguished from non‐functional lutein cells in having a reduced lipid content, well‐developed Golgi complex, abundant tubulo‐vesicular elements of agranular and granular endoplasmic reticulum, non‐motile cilia and a more elaborate folding of the cell membrane into microvillous projections bordering the subendothelial space. The functional significance of these morphological changes of luteal tissue in response to luteotrophin was discussed and correlated with recent biochemical findings of steroidogenic tissue. It was concluded that the presence of luteotrophin following luteinization in mouse ovarian transplants results in numerous morphological changes of luteal tissue which are indicative of progesterone synthesis and secretion. Copyright © 1968 Wiley‐Liss, Inc.