The general long term objectives of the proposed research are to attain a detailed understanding of the biochemistry and physiology of sex-hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG). These are the proteins in plasma to which all of the physiologically important steroid hormones are bound. Although marked alterations in the concentration of both of these proteins in plasma are known to occur in a variety of human conditions i.e. pregnancy, obesity, thyrotoxicosis, hirsutism, polycystic ovary syndrome, and hepatic cirrhosis, among others, our understanding of these changes are at an early stage. Our approach to the understanding of these two proteins during the coming grant period will be multifaceted. We will study the interaction of CBG with its cell membrane receptors. Our model, will be the rat, and we will examine both the physiochemical nature of the interaction and factors which effect it; the physical and functional properties of the receptor; and the organ distribution of the receptor and its endocrine regulation. An animal model exists in which it is possible to cause marked alterations in hepatic CBG concentration in vivo. We will determine the effects of such manipulations on corticosterone metabolism and glucocorticoid receptor translocation to the nucleus. We will affinity label highly purified human CBG and SHBG, and rat CBG, and, after specific enzymatic hydrolysis of the proteins, sequence the affinity labeled peptides to search for homologies in these 3 related but different steroid binding sites. We will use a human hepatoblastoma cell line in vitro both to study endocrine influences on SHBG secretion, and expand our knowledge of the structure of secreted SHBG and its precursor form.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK028562-09
Application #
3228914
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1979-10-01
Project End
1990-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
9
Fiscal Year
1987
Total Cost
Indirect Cost
Name
St. Luke's-Roosevelt Institute for Health Science
Department
Type
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10019
Maitra, U S; Khan, M S; Zhang, X H et al. (1990) The rat hepatic corticosteroid-binding globulin receptor: distinction from the asialoglycoprotein receptor. Endocrinology 127:278-84
Khan, M S; Hryb, D J; Hashim, G A et al. (1990) Delineation and synthesis of the membrane receptor-binding domain of sex hormone-binding globulin. J Biol Chem 265:18362-5
Rosner, W (1990) The functions of corticosteroid-binding globulin and sex hormone-binding globulin: recent advances. Endocr Rev 11:80-91
Nakhla, A M; Khan, M S; Rosner, W (1990) Biologically active steroids activate receptor-bound human sex hormone-binding globulin to cause LNCaP cells to accumulate adenosine 3',5'-monophosphate. J Clin Endocrinol Metab 71:398-404
Khan, M S; Rosner, W (1990) Histidine 235 of human sex hormone-binding globulin is the covalent site of attachment of the nucleophilic steroid derivative, 17 beta-bromoacetoxydihydrotestosterone. J Biol Chem 265:8431-5
Hryb, D J; Khan, M S; Romas, N A et al. (1990) The control of the interaction of sex hormone-binding globulin with its receptor by steroid hormones. J Biol Chem 265:6048-54
Nakhla, A M; Khan, M S; Rosner, W (1988) Induction of adenylate cyclase in a mammary carcinoma cell line by human corticosteroid-binding globulin. Biochem Biophys Res Commun 153:1012-8
Singer, C J; Khan, M S; Rosner, W (1988) Characteristics of the binding of corticosteroid-binding globulin to rat cell membranes. Endocrinology 122:89-96
Strain, G W; Zumoff, B; Miller, L K et al. (1988) Effect of massive weight loss on hypothalamic-pituitary-gonadal function in obese men. J Clin Endocrinol Metab 66:1019-23
Rosner, W; Hryb, D J; Khan, M S et al. (1988) Are corticosteroid-binding globulin and sex hormone-binding globulin hormones? Ann N Y Acad Sci 538:137-45

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