Men have lower high density lipoprotein (HDL) and higher low density lipoprotein (LDL) levels than women. To dynamically evaluate the role of endogenous testosterone on the lipoprotein profile, eight normal men received a long-acting gonadotropin releasing hormone analog (LHRH(A)) for 10 weeks by SC injection. Plasma testosterone levels were acutely lowered below 1 ng/ml after 4 weeks of LHRH(A) treatment and remained depressed at this level for the duration of administration of the analog. There were prompt increases in total cholesterol [baseline vs. peak (milligrams per dl) mean ± SEM, 177 ± 18 vs. 208 ± 22; P<0.005], apoprotein B (apo B; 69 ± 12 vs. 97 ± 13; P<0.05), HDL-cholesterol (23 ± 2 vs. 33 ± 2; P<0.005), and apo A-I (80 ± 7 vs. 112 ± 5; P<0.005), but not in apo A-II (40 ± 3 vs. 40 ± 4; P=NS) levels. The peaks occurred after 10 weeks of treatment and were followed by a fall in these values after discontinuing LHRH(A). These changes were largely prevented in a second study (six men) in which LHRH(A) was administered together with im testosterone enanthate, which was given every 2 weeks. These results show that suppression of endogenous testosterone leads to increases in HDL and LDL, demonstrating that testosterone has an important effect on lipoprotein metabolism and plays a key role in defining the lipoprotein profile in men.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical