STIMULATORY EFFECT OF PROGESTERONE AND 5-ALPHA-PROGESTERONE ON LIPID-SYNTHESIS IN HAMSTER FLANK ORGANS

In order to study lipid synthesis in female hamster flank organs durin g the estrous cycle, glands were obtained from different animals durin g different phases of the cycle. Lipid metabolism of [U-C-14]glucose w as studied Lander in vitro conditions. The radioactive lipids formed w ere extracted from the glands and quantified. An aliquot of the extrac t was submitted to TLC to isolate and identify the lipids formed. Lipi d synthesis in rite glands increased significantly during estrous comp ared with the diestrous phase, suggesting the influence of sex hormone s on lipid metabolism in flank organs. The radioactive lipids isolated and identified were: phospholipids, cholesterol, glycerides, waxes, a nd cholesterol esters. The percentages of conversion from [U-C-14]gluc ose to cholesterol esters were minor in extracts from glands of diestr ous animals as compared to estrous and proestrous animals, whereas gly cerides and waxes increased significantly in metestrous and diestrous animals. To verify and evaluate the role of estrogen and progesterone in lipid synthesis three different groups of gonadectomized female ham sters were injected daily with estradiol, progesterone, and 5 alpha-pr ogesterone. After treatments, glands were incubated with [U-C-14]gluco se to determine the incorporation of radioactive glucose into lipids u nder culture conditions. The radioactive lipids synthesized were subse quently extracted and identified. The results showed that estrogen had no effect on in vitro [U-C-14]glucose incorporation into lipids by fl ank organs, compared to the vehicle, whereas progesterone and 5 alpha- progesterone increased radioactive lipid synthesis by the glands signi ficantly (p < 0.05). The radioactive lipids isolated and identified fr om extracts of gonadectomized female hamster flank organs were: phosph olipids, cholesterol, triglycerides, waxes, and cholesterol esters. Go nadectomy increased phospholipid synthesis and decreased that of monog lycerides, diglycerides, and waxes. The percentages of conversion from [U-C-14]glucose to cholesterol esters were higher after progesterone and 5 alpha-progesterone treatments than in vehicle and estrogen-treat ments. Our data indicate that progesterone and 5 alpha-progesterone-tr eatments increased the in vitro [U-C-14]glucose incorporation into lip ids in flank organs from gonadectomized female hamsters. Furthermore, the major lipid synthesized by glands under these stimuli were cholest erol fatty acids. Thus, progesterone and 5 alpha-progesterone alter th e consistency of sebum from gonadectomized female glands. (C) 1997 by Elsevier Science Inc.