The effect of sex hormones on glycosaminoglycan content of canine aorta and coronary arteries

Abstract

Hyaluronate (HA), heparan sulfate (HS), dermatan sulfate (DS) and isomeric chondroitin sulfates (CS) were measured in vascular walls of 9-10 months old normal and hypophysectomized female beagles treated with sex hormones. Following hypophysectomy the animals were maintained for 8 weeks without any hormonal replacement therapy and then they were exposed for 3 weeks to parenteral treatment with sex hormones. One group received twice weekly 25 mg testosterone, another group was given the same amount of progesterone, and a third group received on day 1 and day 14, estrogens in 2 injections, consisting of a mixture of 10 mg short-acting estradiol-17-phenylpropionate and 2.5 mg long-acting estradiol benzoate. After 11 weeks all animals were sacrificed, coronary arteries and aortas were immediately removed and the latter were divided into three segments: arch, thoracic and abdominal. Removal of the pituitary led to a reduction of the HA content in the aortic arch and thoracic segment, but coronary arteries and abdominal aorta were not affected. The main consequence of hypophysectomy both in the entire aorta and in coronary arteries was a sharp reduction of the sulfated glycosaminoglycan (GAG) content. All three hormones produced a modest rise in the HS content of coronary arteries. A more definite response was seen in the thoracic aorta where each of the three hormones raised the low DS content to normal levels. Concerning the effect of sex hromones on aortic GAG other than DS, TESTOSTERONE RAISED THE CS content towards normal in thoracic and abdominal segments, while estrogen by doubling the normal HA concentration was particularly potent in the abdominal aorta. It is conceivable that the different sensitivity of various segments of aorta and coronary arteries to sex (and other) hormones in terms of regulating GAG metabolism may prove to be of relevance to the uneven distribution of lesions in degenerative vascular disease.