Effects of Androgen Treatment on the Male Rat Aorta

Abstract

A B S T R A C T Androgen was given to male rats to determine if it exerted effects on the aortic wvall distinct from those of estrogen deficit. Although a general anabolic effect was avoided, significant vascular effects were observed. The amounts of mural fibrous proteins, elastin and collagen, were significantly increased in treated animals; noncollagenous, alkali-soluble protein, thought to reflect the cellular component, was unchanged with treatment. These effects were not detectable on microscopic examination and measurement of the vessel wall despite attempts to duplicate closely in vivo wall dimensions before study. These findings of distinct and marked effects of androgen on vascular metabolism extend the growing evidence for an important role of sex hormones in vessel wall structure and function. INTRODUCTIONRecent studies have shown that female sex hormones exert profound effects on vessel wall morphology and metabolism. Estrogens administered to gonadectomized female rats (1, 2) and guinea pigs (3) markedlv reduce the net amount of collagen in the aortic wall and skin. Labeled precursor studies of vascular collagen in females suggest that the mechanism responsible is a combination of accelerated turnover of a relatively small pool of soluble precursors of collagen and interference

Effect of Gender on Development and Diurnal Rhythm of Prostaglandin Receptors in Rat Aorta

“…This is in accord with our observation that from 10 to 16 weeks of age, there occurs a marked increase in the response of the male rat aorta to PGH2. Testosterone also increases the collagen and elastin in aorta of intact male rats (Wolinsky, 1972b) but does not affect the non-fibrous components (i.e. smooth muscle) of the male rat aorta (Wolinsky, 1972a).…”

Effect of Sex Hormones on Rabbit Arterial Subendothelial Connective Tissue

“…These changes are apparently a reflection of previously described alterations in both collagen and elastin metabolism [4][5][6]. Since it has been found that morphologically different subendothelial connective tissue elements exhibit different degrees of thrombogenicity when exposed to flowing blood [7][8][9][10], these observa tions may have significant implications in human disease.…”

“…Although biochemical effects of sex hormones on vascular connective tissue have been reported, to date structural correlations have not been made [4][5][6], Pertinent to this subject is the observation that the thrombogenicity of subendothelial connective tissue varies significantly according to differences in predominant connective tissue components [7][8][9][10][11], Therefore, an effect of sex hormones on subendothelial connective tissue in rabbit arteries was sought, and striking morphological alterations were indeed encountered.…”

Canine vascular tissues are targets for androgens, estrogens, progestins, and glucocorticoids.

“…Cavallero et al (47) find that in cholesterol-fed rabbits, aortic smooth muscle replication is inhibited by exogenous glucocorticoids. Finally, thickening and hardening of blood vessels in vascular diseases is largely a fibrotic process, and sex steroids have been implicated in the control of collagen and elastin synthesis in these vessels: in general it seems that progesterone and androgens increase (13)(14)(15) and estrogens decrease (15,48) collagen and elastin deposition in aortic smooth muscle cells in vivo and in culture. In sum, the data point to an inhibitory role for estrogens and glucocorticoids, and a stimulatory role for androgens and progestins, in vascular smooth muscle proliferative and/or hypertrophic activity.…”

“…Estrogen alters hemodynamics in women and in experimental animals (10)(11)(12). Exogenous androgen, estrogen, or progesterone cause morphological and histochemical changes in animal aortas (13)(14)(15). Exogenous glucocorticoids or conditions characterized by excessive endogenous glucocorticoid production may be associated with systemic hypertension (16)(17)(18).…”