Przybylska B, Wyrzykowski Z, Kaleczyc J
Department of Histology and Embryology, Veterinary Faculty University of Agriculture and Technology, Olsztyn, Poland.
Steroids. 1993 Oct;58(10):466-71. doi: 10.1016/0039-128x(93)90004-7.
The ultrastructure of female pig pinealocytes was studied after ovariectomy alone and ovariectomy followed by administration of estradiol, progesterone, or both. Administration of estradiol as well as a combination of estradiol and progesterone induced qualitative ultrastructural changes in pinealocytes relative to Golgi apparatus and cytoplasmic dense bodies as well as quantitative ones, such as a decrease in relative volume of cytoplasmic dense bodies and lysosomes. Administration of progesterone caused the formation of dense bodies and a decrease in the relative volume of lysosomes. The results point to a relationship between the pineal gland and gonads in the pig and suggest that gonadal steroids, particularly estradiol, could be involved in a feedback mechanism of the hypothalamic-hypophyseal-gonadal system to the pineal gland.
