ULTRASTRUCTURAL CHANGES OF THE CORPORA-LUTEA IN LH-TREATED CYCLIC FEMALE RATS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 93  (2) , 266-282
Abstract
As LH [luteinizing hormone] is capable of stimulating ovarian progesterone [P] secretion at the beginning of 4 day cycles, an attempt was made to determine whether corpora lutea formed at the end of a preceding cycle are responsible for the increase in ovarian P secretion. Cyclic female rats (4 day) were injected with LH on diestrus I at 0800-0900 h (64 .mu.g/100 g per body wt expressed in terms of NIH-LH-S3). An increase in the peripheral blood P concentration occurred on the morning of diestrus II in LH-treated females when compared to control females. Concomitantly enlarged mitochondria, numerous membranes of the smooth endoplasmic reticulum and a decrease in the number of lipid droplets were observed in LH-treated females. Inversely, signs of involution of the corpora lutea were noted from the morning of diestrus I to that of diestrus II in noninjected females. LH-induced P increase at diestrus II results from the activation of the corpora lutea formed at the end of the preceding cycle.