Clinical Endocrinology (1992) 36, 351-353
Growth hormone binding protein in Werner’s syndrome Naoki Hattorl, Megumu Hino*, KatsuJlIkekubo*, Takashi Ishlhara, Kunisaburo Moridera and Hlroyuki Kurahachi Departments of Endocrinology and ‘Nuclear Medicine, Kobe City Genera/ Hospital, Kobe 650, Japan (Received 21 August 1991; returned for revision 10 October 1991; finally revised 21 October 1991; accepted 15 November 1991)
Summary OBJECTIVE GH and growth hormone binding protein in Werner’s syndrome were investigated to elucldate their relation to the short stature. DESIGN The levels of GH binding protein and GH response to Insulin-Induced hypoglycaemia were determlned. GH binding protein levels and Its Scatchard analysis In Werner’s syndrome were comparedwith those In normal subjects. PATIENTS Three patients with Werner’s syndrome (one man aged 45 years and two women aged 39 and 38 years) and 41 normal subjects (18 men and 23 women aged 39.3f 5.5 years, mean f SD) were studied. MEASUREMENTS GH binding protein levels were determined using an Ultrogel AcA44 minlcolumnand GH levels were measured by a highly sensitive enzyme immunoassay. RESULTS Two out of three pattents with Werner’s syndrome had GH binding protein levels above the mean 2SD value in normal subjects. GH secretion was impaired in Werner’s syndrome as judged by the low GH response to insulin-inducedhypoglycaemia. CONCLUSIONS Elevated GH binding protein levels may lead to an increase in the bound form of OH, which Is probably less bloactive, resulting in growth failure In association with the impaired GH secretion in Werner’s syndrome.
+
Werner’s syndrome, first described by Otto Werner (1904), is a rare autosomal recessive disorder in which young adults display clinical features similar to those in elderly people. They include premature graying of the hair and baldness, arteriosclerosis, atrophic skin changes, juvenile cataracts, short stature, hypogonadism and a tendency to develop Correspondence: Dr Naoki Hattori. Department of Endocrinology, Kobe City General Hospital, 4-6 Minatojima Nakamachi, Chuo-ku, Kobe 650, Japan.
diabetes mellitus and neoplasms (Thannhauser, 1945; Epstein et al., 1966; Goto et al., 1981). Growth hormone secretion was investigated with great interest because of the characteristic failure of the growth spurt during adolescence in Werner’s syndrome, although the results were controversial (Alberti et al., 1974; Imura et al., 1985; Nakao et al., 1978). Growth hormone binding protein (GHBP) was recently detected in human serum (Baumann et al., 1986; Herington et al., 1986). GHBP levels progressively increase with age during the first two decades in both sexes (Daughaday et al., 1987). After the age of 40 years, however, they decrease in men but not in women (Hattori et al., 1991). In the present preliminary study, we examined GHBP in Werner’s syndrome. Materials and methods
We studied three patients with Werner’s syndrome (one man aged 45 years and two women aged 39 and 38 years) and 41 normal subjects (18 men and 23 women, aged 39.3k5.5 years, mean+ SD). The diagnosis of Werner’s syndrome was based on typical clinical manifestations of this syndrome. The clinical characteristics of the patients are summarized in Table 1. Blood was taken early in the morning after an overnight fast and the serum was stored at -20°C. Insulin (0.1 U/kg) was injected intravenously and G H response to
Table 1 Clinical characteristicsof patients with Werner’s syndrome Case
Age (years) Sex Short stature Consanguinity Familial occurrence Atrophy and hyperkeratosisof the skin Juvenile cataracts Premature graying of the hair or baldness High pitched voice Hypogonadism Impaired glucose tolerance Neoplasms
1
2
3
39 F
45 M
38 F
+ + + + + + +
+ + + + + + + +
+
+ + + + + +
+
+
+ Presence of the symptoms. 351
352
N. Hattori et al.
Clinical Endocrinology (1992) 36
Table 2 GH response to insulin-inducedhypoglycaemia, GHBP
levels and the binding data in Werner’s syndrome Peak GH during insulin-induced BasalGH hypoglycaemia GHBP Ka Case (mUj1) (mum (%) ( x lo8 M - I ) 1 2 3
1.7 2.1 0.6
3.6 7.5
ND
33.7 39.6 21.2
I .9 1.2 2.1
Bmax (mu/l) 119.8 f 78.4 64.2
ND Not determined.
insulin-induced hypoglycaemia was examined in cases 1 and 2. The study was approved by the local ethical committee of Kobe City General Hospital. GH binding study
GHBP levels were determined using a minicolumn method (Herington el al., 1986) with slight modification. Serum (0.4mi) was incubated in 0.01 mol/l sodium phosphate buffer @H 7.0) containing 0.1 mol/l NaCl, 0.1% BSA and 0.1 % NaN3 at 37°C for 60 min with lZ5I G H (15 000-20 000 c.p.m.; about 0.3-0.4 ng) in a final volume of 0.5 ml. Free GH was separated from bound G H by an Ultrogel AcA44 minicolumn (0.9 x 25 cm) at 4°C. Samples were eluted with the same buffer and 0.5 ml fractions were collected. Nonspecific binding was determined by adding excess unlabelled GH (0.4 pg/lO p1 phosphate buffer) and specific binding was calculated by subtracting non-specific binding from total binding. Coefficient of variation of GHBP levels in pooled reference serum was 6.7%. Enzyme imrnunoassay (EIA) for GH
Serum GH concentrations were measured in duplicate by a highly sensitive EIA which was previously reported (Hattori et al., 1990). The detection limit for 20 pl serum samples was 0.003 mU/1. The intra and inter-assay coefficients of variation were 6.0 and 8.6%, respectively. All data were expressed as means fSD. Results
Basal GH levels and the response to insulin-induced hypoglycaemia in patients with Werner’s syndrome are listed in Table 2. Cases 1 and 2 showed a low response of serum GH to insulin-induced hypoglycaemia.
Serum GHBP levels and the binding data in patients with Werner’s syndrome are shown in Table 2. GHBP levels in normal subjects ranged from 13.1 to 32.9% (mean fSD; 22.8f4.8%). Two out of the three patients with Werner’s syndrome had GHBP levels above the mean+2SD value of GHBP in normal subjects. Scatchard analysis on serum from six normal subjects showed that the association constant (Ka) was 2 . 3 f 0 . 7 ~lo8 M - I and the maximum binding capacity (Bmax) was 56.6f 17.8 mu/]). Ka was within the normal range in all patients with Werner’s syndrome, while two out of the three patients who had elevated GHBP levels showed an increase in Bmax above the mean 2SD value in normal subjects.
+
Discussion
Growth hormone secretion has been reported to be impaired in Werner’s syndrome far more frequently than in normal subjects (Alberti et al., 1974; Imura ef al., 1985), while Nakao et af. (1978) reported normal G H secretion in two of three patients. The present cases showed low response of GH to insulin-induced hypoglycaemia. It is speculated that the absence of a growth spurt during adolescence may be attributable to impaired GH secretion resulting in short stature. Growth hormone binding protein (GHBP) was detected in human serum and is thought to be derived from hepatic G H receptors (Leung et af., 1987). About 50% of circulating G H is complexed with GHBP (Baumann et al., 1988). To our knowledge, this is the first report concerning GHBP in Werner’s syndrome. The present preliminary data showed that GHBP levels in Werner’s syndrome were higher than those in normal subjects and that the elevation was due to an increase in the binding capacity. Since the binding protein competes with the receptors for GH binding, complexed G H is less likely than free GH to interact with the receptors, resulting in reduced bioactivity (Mannor et af., 1991). The effect of corticosteroid binding globulin, sex hormone binding globulin and insulin-like growth factor binding proteins on the biological activity of the hormones is analogous (Pardridge, 1981; Siiteri et al., 1982; Zapf et al., 1975). Inappropriately elevated GHBP levels may lead to an increase in complexed GH, which is probably less bioactive, resulting in growth failure in association with the impaired G H secretion in Werner’s syndrome. The reason for increased GHBP levels in Werner’s syndrome is unclear. Impaired G H secretion is unlikely to cause an increase in GHBP levels, since it has recently reported that patients with isolated G H deficiency had a very low level of GHBP activity (Postel-Vinay el al., 1991). Unusually high
GH binding protein in Werner’s syndrome
Clinical Endocrinology (1992) 36
levels of corticosteroid binding globulins were reported in patients with haematological disorders and their relatives, indicating the connection with HLA antigens (Moor et al., 1980). Genetic abnormalities may be involved in high GHBP levels in Werner’s syndrome. References Alberti, K.G.M.M., Young, J.D.H. & Hockaday, T.D.R. (1974) Werner’s syndrome: metabolic observations. Proceedings of the Royal Society of Medicine, 67, 36-38. Baumann, G., Amburn, K. & Shaw, M.A. (1988) The circulating growth hormone (GH)-binding protein complex: a major constituent of plasma GH in man. Endocrinology, 122,976-984. Baumann, G., Stolar, M.W., Amburn, K., Barsano, C.P. & DeVries, B.C. (1986) A specific growth hormone-binding protein in human plasma: initial characterization. Journal of Clinical Endocrinology and Metabolism, 62, 134-141. Daughaday, W.H., Trivedi, B. & Andrews, B.A. (1987) The ontogeny of serum GH binding protein in man: a possible indicator of hepatic GH receptor development. Journalof Clinical Endocrinology and Metabolism, 65, 1072-1074. Epstein,C.J., Martin,G.M.,Schultz,A.L.&Motulsky,A.G.(1966) Werner’s syndrome: a review of its symptomatology, natural history, pathologic features, genetics and relationship to the natural aging process. Medicine, 45, 177-221. Goto, M., Tanimoto, K., Horiuchi, Y. & Sasatsuji, T. (1981) Family analysis of Werner’s syndrome: a survey of 42 Japanese families with a review of the literature. Clinical Genetics, 19,8-15. Hattori,N., Kurahachi, H., Ikekubo, K., Ishihara,T., Moridera, K., Hino, M., Saiki, Y. & Imura, H. (1991) Effects ofsex and age on serum GH binding protein levels in normal adults. Clinical Endocrinology, 35,295-297. Hattori, N., Shimatsu, A,, Kato, Y., Koshiyama, H., Ishikawa, Y., Assadian, H., Tanoh, T., Nagao, M. & Imura, H. (1990) Growth hormone responses to oral glucose loading measured by highly sensitive enzyme immunoassay in normal subjects and patients with glucose intolerance and acromegaly. Journal of Clinical Endocrinology and Metabolism, 70, 77 1-176. Herington, A.C., Ymer, S. &Stevenson, J. (1986) Identification and characterization of specific binding proteins for growth hormone in normal human sera. Journal of Clinical Investigation, 77,18171823.
353
Imura, H., Nakao, Y., Kuzuya, H., Okamoto, M., Okamoto, M. & Yamada, K. (1985) Clinical, endocrine and metabolic aspects of the Werner syndrome compared with those of normal aging. Advances in Experimental Medicine and Biology, 190, 17 1-185. Leung, D.W., Spencer, S.A., Cachianes, G., Hammonds, R.G., Collins, C., Henzel, W.J., Barnard, R., Waters, M.J. & Wood, W.I. (1987) Growth hormone receptor and serum binding protein: purification, cloning and expression. Nature, 330, 537-543. Mannor, D.A., Winer, L.M., Shaw, M.A. & Baumann, G. (1991) Plasma growth hormone (GH)-binding proteins: effect on GH binding to receptors and GH action. Journal of Clinical Endocrinology and Metabolism, 73, 30-34. Moor, P., Louwagie, A., Baelen, H.V. & Putte, I.V. (1980) Unexplained high transcortin levels in patients with various hematological disorders and in their relatives: a connection between these high transcortin levels and HLA antigen B12. Journal of Clinical Endocrinology and Metabolism, 50,421 -426. Nakao, Y., Kishihara, M., Yoshimi, H., Inoue, Y., Tanaka, K., Sakamoto, N., Matsukura, S., Imura, H., Ichihashi, M. & Fujiwara, Y. (1978) Werner’s syndrome: in vivo and in vitro characteristics as a model of aging. American Journal of Medicine, 65,919-932.
Pardridge, W.M. (198 I ) Transport of protein-bound hormones into tissues in vivo. Endocrine Reviews, 2, 103-123. Postel-Vinay, M.C., Tar, A,, Hocquette. J.F., Clot. J.P., Fontoura, M., Brauner, R. & Rappaport. R. (1991) Human plasma growth hormone (GH)-binding proteins are regulated by GH and testosterone. Journal of Clinical Endocrinology and Metabolism, 73, 197-202.
Siiteri, P.K., Murai, J.T., Hammond, G.L., Nisker, J.A., Raymoure, W.J. & Kuhn R.W. (1982) The serum transport of steroid hormones. Recent Progress in Hormone Research, 38,457-5 10. Thannhauser. S.J. (1945) Werner’s syndrome (progeria of the adult) and Rothmund’s syndrome: two types of closely related heredofamilial atrophicdermatosis with juvenile cataracts and endocrine features. A critical study with five new cases. Annuls oflnternal Medicine, 23, 5 59. Werner, 0. (1904) uber Katarakt in Verbindung mit Sklerodermie (doctoral dissertaion, Kiel University). Schmidt and Klauning, Kiel. Zapf, J., Waldvogel, M. & Froesch, E.R. (1975) Binding of nonsuppressible insulin-like activity to human serum: evidence for a carrier protein. Archives of Biochemistry and Biophysics, 168, 638-645.
Growth hormone binding protein in Werner’s syndrome Naoki Hattorl, Megumu Hino*, KatsuJlIkekubo*, Takashi Ishlhara, Kunisaburo Moridera and Hlroyuki Kurahachi Departments of Endocrinology and ‘Nuclear Medicine, Kobe City Genera/ Hospital, Kobe 650, Japan (Received 21 August 1991; returned for revision 10 October 1991; finally revised 21 October 1991; accepted 15 November 1991)
Summary OBJECTIVE GH and growth hormone binding protein in Werner’s syndrome were investigated to elucldate their relation to the short stature. DESIGN The levels of GH binding protein and GH response to Insulin-Induced hypoglycaemia were determlned. GH binding protein levels and Its Scatchard analysis In Werner’s syndrome were comparedwith those In normal subjects. PATIENTS Three patients with Werner’s syndrome (one man aged 45 years and two women aged 39 and 38 years) and 41 normal subjects (18 men and 23 women aged 39.3f 5.5 years, mean f SD) were studied. MEASUREMENTS GH binding protein levels were determined using an Ultrogel AcA44 minlcolumnand GH levels were measured by a highly sensitive enzyme immunoassay. RESULTS Two out of three pattents with Werner’s syndrome had GH binding protein levels above the mean 2SD value in normal subjects. GH secretion was impaired in Werner’s syndrome as judged by the low GH response to insulin-inducedhypoglycaemia. CONCLUSIONS Elevated GH binding protein levels may lead to an increase in the bound form of OH, which Is probably less bloactive, resulting in growth failure In association with the impaired GH secretion in Werner’s syndrome.
+
Werner’s syndrome, first described by Otto Werner (1904), is a rare autosomal recessive disorder in which young adults display clinical features similar to those in elderly people. They include premature graying of the hair and baldness, arteriosclerosis, atrophic skin changes, juvenile cataracts, short stature, hypogonadism and a tendency to develop Correspondence: Dr Naoki Hattori. Department of Endocrinology, Kobe City General Hospital, 4-6 Minatojima Nakamachi, Chuo-ku, Kobe 650, Japan.
diabetes mellitus and neoplasms (Thannhauser, 1945; Epstein et al., 1966; Goto et al., 1981). Growth hormone secretion was investigated with great interest because of the characteristic failure of the growth spurt during adolescence in Werner’s syndrome, although the results were controversial (Alberti et al., 1974; Imura et al., 1985; Nakao et al., 1978). Growth hormone binding protein (GHBP) was recently detected in human serum (Baumann et al., 1986; Herington et al., 1986). GHBP levels progressively increase with age during the first two decades in both sexes (Daughaday et al., 1987). After the age of 40 years, however, they decrease in men but not in women (Hattori et al., 1991). In the present preliminary study, we examined GHBP in Werner’s syndrome. Materials and methods
We studied three patients with Werner’s syndrome (one man aged 45 years and two women aged 39 and 38 years) and 41 normal subjects (18 men and 23 women, aged 39.3k5.5 years, mean+ SD). The diagnosis of Werner’s syndrome was based on typical clinical manifestations of this syndrome. The clinical characteristics of the patients are summarized in Table 1. Blood was taken early in the morning after an overnight fast and the serum was stored at -20°C. Insulin (0.1 U/kg) was injected intravenously and G H response to
Table 1 Clinical characteristicsof patients with Werner’s syndrome Case
Age (years) Sex Short stature Consanguinity Familial occurrence Atrophy and hyperkeratosisof the skin Juvenile cataracts Premature graying of the hair or baldness High pitched voice Hypogonadism Impaired glucose tolerance Neoplasms
1
2
3
39 F
45 M
38 F
+ + + + + + +
+ + + + + + + +
+
+ + + + + +
+
+
+ Presence of the symptoms. 351
352
N. Hattori et al.
Clinical Endocrinology (1992) 36
Table 2 GH response to insulin-inducedhypoglycaemia, GHBP
levels and the binding data in Werner’s syndrome Peak GH during insulin-induced BasalGH hypoglycaemia GHBP Ka Case (mUj1) (mum (%) ( x lo8 M - I ) 1 2 3
1.7 2.1 0.6
3.6 7.5
ND
33.7 39.6 21.2
I .9 1.2 2.1
Bmax (mu/l) 119.8 f 78.4 64.2
ND Not determined.
insulin-induced hypoglycaemia was examined in cases 1 and 2. The study was approved by the local ethical committee of Kobe City General Hospital. GH binding study
GHBP levels were determined using a minicolumn method (Herington el al., 1986) with slight modification. Serum (0.4mi) was incubated in 0.01 mol/l sodium phosphate buffer @H 7.0) containing 0.1 mol/l NaCl, 0.1% BSA and 0.1 % NaN3 at 37°C for 60 min with lZ5I G H (15 000-20 000 c.p.m.; about 0.3-0.4 ng) in a final volume of 0.5 ml. Free GH was separated from bound G H by an Ultrogel AcA44 minicolumn (0.9 x 25 cm) at 4°C. Samples were eluted with the same buffer and 0.5 ml fractions were collected. Nonspecific binding was determined by adding excess unlabelled GH (0.4 pg/lO p1 phosphate buffer) and specific binding was calculated by subtracting non-specific binding from total binding. Coefficient of variation of GHBP levels in pooled reference serum was 6.7%. Enzyme imrnunoassay (EIA) for GH
Serum GH concentrations were measured in duplicate by a highly sensitive EIA which was previously reported (Hattori et al., 1990). The detection limit for 20 pl serum samples was 0.003 mU/1. The intra and inter-assay coefficients of variation were 6.0 and 8.6%, respectively. All data were expressed as means fSD. Results
Basal GH levels and the response to insulin-induced hypoglycaemia in patients with Werner’s syndrome are listed in Table 2. Cases 1 and 2 showed a low response of serum GH to insulin-induced hypoglycaemia.
Serum GHBP levels and the binding data in patients with Werner’s syndrome are shown in Table 2. GHBP levels in normal subjects ranged from 13.1 to 32.9% (mean fSD; 22.8f4.8%). Two out of the three patients with Werner’s syndrome had GHBP levels above the mean+2SD value of GHBP in normal subjects. Scatchard analysis on serum from six normal subjects showed that the association constant (Ka) was 2 . 3 f 0 . 7 ~lo8 M - I and the maximum binding capacity (Bmax) was 56.6f 17.8 mu/]). Ka was within the normal range in all patients with Werner’s syndrome, while two out of the three patients who had elevated GHBP levels showed an increase in Bmax above the mean 2SD value in normal subjects.
+
Discussion
Growth hormone secretion has been reported to be impaired in Werner’s syndrome far more frequently than in normal subjects (Alberti et al., 1974; Imura ef al., 1985), while Nakao et af. (1978) reported normal G H secretion in two of three patients. The present cases showed low response of GH to insulin-induced hypoglycaemia. It is speculated that the absence of a growth spurt during adolescence may be attributable to impaired GH secretion resulting in short stature. Growth hormone binding protein (GHBP) was detected in human serum and is thought to be derived from hepatic G H receptors (Leung et af., 1987). About 50% of circulating G H is complexed with GHBP (Baumann et al., 1988). To our knowledge, this is the first report concerning GHBP in Werner’s syndrome. The present preliminary data showed that GHBP levels in Werner’s syndrome were higher than those in normal subjects and that the elevation was due to an increase in the binding capacity. Since the binding protein competes with the receptors for GH binding, complexed G H is less likely than free GH to interact with the receptors, resulting in reduced bioactivity (Mannor et af., 1991). The effect of corticosteroid binding globulin, sex hormone binding globulin and insulin-like growth factor binding proteins on the biological activity of the hormones is analogous (Pardridge, 1981; Siiteri et al., 1982; Zapf et al., 1975). Inappropriately elevated GHBP levels may lead to an increase in complexed GH, which is probably less bioactive, resulting in growth failure in association with the impaired G H secretion in Werner’s syndrome. The reason for increased GHBP levels in Werner’s syndrome is unclear. Impaired G H secretion is unlikely to cause an increase in GHBP levels, since it has recently reported that patients with isolated G H deficiency had a very low level of GHBP activity (Postel-Vinay el al., 1991). Unusually high
GH binding protein in Werner’s syndrome
Clinical Endocrinology (1992) 36
levels of corticosteroid binding globulins were reported in patients with haematological disorders and their relatives, indicating the connection with HLA antigens (Moor et al., 1980). Genetic abnormalities may be involved in high GHBP levels in Werner’s syndrome. References Alberti, K.G.M.M., Young, J.D.H. & Hockaday, T.D.R. (1974) Werner’s syndrome: metabolic observations. Proceedings of the Royal Society of Medicine, 67, 36-38. Baumann, G., Amburn, K. & Shaw, M.A. (1988) The circulating growth hormone (GH)-binding protein complex: a major constituent of plasma GH in man. Endocrinology, 122,976-984. Baumann, G., Stolar, M.W., Amburn, K., Barsano, C.P. & DeVries, B.C. (1986) A specific growth hormone-binding protein in human plasma: initial characterization. Journal of Clinical Endocrinology and Metabolism, 62, 134-141. Daughaday, W.H., Trivedi, B. & Andrews, B.A. (1987) The ontogeny of serum GH binding protein in man: a possible indicator of hepatic GH receptor development. Journalof Clinical Endocrinology and Metabolism, 65, 1072-1074. Epstein,C.J., Martin,G.M.,Schultz,A.L.&Motulsky,A.G.(1966) Werner’s syndrome: a review of its symptomatology, natural history, pathologic features, genetics and relationship to the natural aging process. Medicine, 45, 177-221. Goto, M., Tanimoto, K., Horiuchi, Y. & Sasatsuji, T. (1981) Family analysis of Werner’s syndrome: a survey of 42 Japanese families with a review of the literature. Clinical Genetics, 19,8-15. Hattori,N., Kurahachi, H., Ikekubo, K., Ishihara,T., Moridera, K., Hino, M., Saiki, Y. & Imura, H. (1991) Effects ofsex and age on serum GH binding protein levels in normal adults. Clinical Endocrinology, 35,295-297. Hattori, N., Shimatsu, A,, Kato, Y., Koshiyama, H., Ishikawa, Y., Assadian, H., Tanoh, T., Nagao, M. & Imura, H. (1990) Growth hormone responses to oral glucose loading measured by highly sensitive enzyme immunoassay in normal subjects and patients with glucose intolerance and acromegaly. Journal of Clinical Endocrinology and Metabolism, 70, 77 1-176. Herington, A.C., Ymer, S. &Stevenson, J. (1986) Identification and characterization of specific binding proteins for growth hormone in normal human sera. Journal of Clinical Investigation, 77,18171823.
353
Imura, H., Nakao, Y., Kuzuya, H., Okamoto, M., Okamoto, M. & Yamada, K. (1985) Clinical, endocrine and metabolic aspects of the Werner syndrome compared with those of normal aging. Advances in Experimental Medicine and Biology, 190, 17 1-185. Leung, D.W., Spencer, S.A., Cachianes, G., Hammonds, R.G., Collins, C., Henzel, W.J., Barnard, R., Waters, M.J. & Wood, W.I. (1987) Growth hormone receptor and serum binding protein: purification, cloning and expression. Nature, 330, 537-543. Mannor, D.A., Winer, L.M., Shaw, M.A. & Baumann, G. (1991) Plasma growth hormone (GH)-binding proteins: effect on GH binding to receptors and GH action. Journal of Clinical Endocrinology and Metabolism, 73, 30-34. Moor, P., Louwagie, A., Baelen, H.V. & Putte, I.V. (1980) Unexplained high transcortin levels in patients with various hematological disorders and in their relatives: a connection between these high transcortin levels and HLA antigen B12. Journal of Clinical Endocrinology and Metabolism, 50,421 -426. Nakao, Y., Kishihara, M., Yoshimi, H., Inoue, Y., Tanaka, K., Sakamoto, N., Matsukura, S., Imura, H., Ichihashi, M. & Fujiwara, Y. (1978) Werner’s syndrome: in vivo and in vitro characteristics as a model of aging. American Journal of Medicine, 65,919-932.
Pardridge, W.M. (198 I ) Transport of protein-bound hormones into tissues in vivo. Endocrine Reviews, 2, 103-123. Postel-Vinay, M.C., Tar, A,, Hocquette. J.F., Clot. J.P., Fontoura, M., Brauner, R. & Rappaport. R. (1991) Human plasma growth hormone (GH)-binding proteins are regulated by GH and testosterone. Journal of Clinical Endocrinology and Metabolism, 73, 197-202.
Siiteri, P.K., Murai, J.T., Hammond, G.L., Nisker, J.A., Raymoure, W.J. & Kuhn R.W. (1982) The serum transport of steroid hormones. Recent Progress in Hormone Research, 38,457-5 10. Thannhauser. S.J. (1945) Werner’s syndrome (progeria of the adult) and Rothmund’s syndrome: two types of closely related heredofamilial atrophicdermatosis with juvenile cataracts and endocrine features. A critical study with five new cases. Annuls oflnternal Medicine, 23, 5 59. Werner, 0. (1904) uber Katarakt in Verbindung mit Sklerodermie (doctoral dissertaion, Kiel University). Schmidt and Klauning, Kiel. Zapf, J., Waldvogel, M. & Froesch, E.R. (1975) Binding of nonsuppressible insulin-like activity to human serum: evidence for a carrier protein. Archives of Biochemistry and Biophysics, 168, 638-645.
