The Establishment Of Androgen Receptor Binding Assay And Measurement Of 5α-reductase Activity, And Their Preliminary Clinical Application.

In order to investigate the etiology in patients with sex differentiation disorder, the AR-binding assay and measurement of 5α-reductase activity had been established with the intact genital skin fibroblast monolayers.The Bmax , K_d values of AR, at 37 ℃ and 42 ℃ and 5α-reductase activity had been measured in 8 male control subjects with phimosis, 5 cases with simple male hypospadias and one female case with kyrotype 46,XY, and dominant female genital phenotypic characters, whose ratio of serum T/DHT was 100 (397ng/dl/3.9ng/dl) We observed that: I): The Bmax of AR in 8 controls at 37 ℃ and 42 ℃ were 80.32±30.94fmol/mg protein [(x±s), range: 48.24 ~ 119.94fmol/mg protein] and 82.80±28.91fmol/mg protein (42.50 ~ 124.36 fmol/mg protein) respectively; Kd values of AR were 0.46±0.21nM (range: 0.24~0.78nM) and 0.54 ± 0.22nM (0.30~0.83nM) respectively. There are not different significantly between Bmax or Kd values at 37 ℃ and 42 ℃ (p>0.05). In the pseudohermaphrodite patient the Bmax of AR was 68.83 fmol / mg protein at 37 ℃ and 87.64 fmol / mg protein at 42 ℃ respectively; Kd values were 0.24nM at 37 ℃ and 0.26nM at 42 ℃ respectively. Both Bmax and Kd values fall in the normal range in 8 controls. II) The 5a-reductase activity in 8 controls was 7.00±9.41 pmol/mg protein ·h [(x±s), range 1.08~23.21pmol/mg protein·h].. The 5α-reductase activity in 5 cases with simple male hypospadias was 1.56±0.42 pmol/mg protein ·h( 1.13~2.04pmol /mg protein ·h), There was not different significantly compared with normal controls (p>0.05). The 5α-reductase activity in the patient with pseudohermaphroditism was 0.39 pmol/mg protein ·h(0.34 , 0.46 and 0.36 pmol/mg protein ·h in respective three times). This value was below the minimum of the controls.The results suggest that: i). At 37 ℃ and 42 ℃ Bmax and Kd value remain constant. These results demonstrated that AR is structural stable in normal subject, under conditions of the temperature increasing from 37 ℃ to 42 ℃ . ii). The 5α-reductase activity value in normal male subject is higher than 1.08 pmol/mg protein ·h, although there are apparent variation among mormal male individuals. The causes of apparent androgen insensitivity and 5α-reductase dificiency may be excluded in the 5 cases with simple male hypospadias. iii) The pseudohermaphrodite patient can be diagnosed primary 5α-reductase deficiency because of normal Bmax and K_d value and lower 5α-reductase activity value than the minimum value determined in 8 controls.