Autoradiographic and Biochemical Studies of Hormone Receptor Localization,

Abstract

Autoradiography has been used in the past to locate presumptive receptor systems for a number of steroids. It has provided information in rather complex tissues that could not have been obtained by biochemical procedures. In these studies we made use of autoradiography to redirect our biochemical efforts to study androgen receptors in the primate heart. Castrated-adrenalectomized female rhesus monkeys and baboons were injected with 1 teg of 5 adihydro-[1,2,4,5,6,7 3H1-testosterone per kilogram of body weight. The animals were killed 1 hour later and the hearts were removed and processed for autoradiography.A nuclear localization of androgen was found in most of the myocardial cells, but in few if any of the interstitial cells. After reviewing the autoradiographic data, we began a new series of biochemical studies using a new buffer system and unlabeled androgen to stabilize the receptor. This in combination with postlabeled gradients allowed us to demonstrate for the first time 8S binding on sucrose density gradients. We feel that autoradiography can be a useful adjunct to biochemical studies even in "less complex" tissue such as the cardiac muscle.

Heart contains receptors for dihydrotestosterone but not testosterone: Possible role in the sex differential in coronary heart disease

“…2). This is in sharp contrast to two previous studies using 3H-DHT, in which a heavy and distinct labeling was found in both female rhesus monkeys (McGill et al, 1980;Sheridan et al, 1981) and male and female baboons (McGill and Sheridan, 1981;Sheridan et al, 1981). For comparison, autoradiograms from male baboons injected with 3H-DHT are shown exhibiting a nuclear localization in both the heart (Fig.…”

“…Our first conclusion, that circulating DHT is the main androgen acting on the baboon cardiovascular system, is based on both the autoradiographic data from this study and on previous studies (McGill et al, 1980;McGill and Sheridan, 1981;Sheridan et al, 1981) and previous metabolism studies (Lin et al, 1981). In our earlier studies (McGill et al, 1980;McGill and Sheridan, 1981;Sheridan et al, 1981), we found a consistent, well defined nuclear uptake of 3H-DHT in both the myocardium and smooth muscle cells of all arteries investigated. In the present study, we did not find any nuclear uptake and retention of 3H-testosterone in the myocardium or smooth muscle cells of arteries in any of the animals injected with the hormone.…”

“…Therefore, the sum of the data suggests that, even though the androgen receptors in the cardiovascular system are exposed to unmetabolized testosterone, they do not take up and retain testosterone. In addition, even though DHT is rapidly metabolized by the myocardial cytosol (Lin et al, 19811, in vivo nuclear uptake and retention are observed after the injection of 3H- DHT (McGill et al, 1980;McGill and Sheridan, 1981;Sheridan et al, 1981).…”

“…We also demonstrated androgen receptor in cytosolic preparations from the baboon heart (McGill et d . , 1980;Sheridan et al, 1981). These studies have been extended to include a more complete biochemical characterization of androgen binding in the cardiovascular system of the baboon (Lin et al, 1981(Lin et al, , 1985.…”

Adaptation of cardiac morphology and function to endurance and strength training

“…For example, males and females do not respond equally when exposed to acute training (Higginbotham, Morris, Coleman, Cobb, 1984; Hanley, Zinsmeister, Clements, Bove, Brown, Gibbons, 1989). Compared to females, males respond with greater cardiac muscular hypertrophy for the same amount of training, which may be due to testosterone receptors found in cardiac muscular tissue since testosterone is a growth factor for cardiac tissue (McGill & Sheridan, 1981; Sheridan, Buchanan, Anselmo, 1981).…”