抄録
The first successful analysis of TRH in serum and urine was performed by mass fragmentography using a GC-MS combined system. In developing our method, the first problem we had to solve was that of forming a volatile, stable derivative of TRH. TRH was methylated by addition of ethereal-alcoholic solution of diazomethane. This derivative was most useful for GLC work.
The equipment used was Shimadzu LKB 9000 GC-MS (MID-PM). The methylated derivative of TRH was analyzed using the GC-MS system equipped with a 3 ft × 3 mm column packed with 1.5% OV-1 and the temperature was programed at 260°C.
The mass spectrum showed molecular ion at m/e 390 which corresponds to the dimethyl derivative of TRH. The base peak at m/e 149 was applied to establish the precise quantitative evaluation of TRH and related compounds by mass fragmentography.
Inactivation of TRH by serum and urine was well documented. Urines were collected and kept at pH 3 over a 24-hr period. Specimens were stored at -20°C until extraction and assay. Blood samples were collected into polystyrene tubes containing 5mg BAL (2, 3- dimercaptopropanol) and kept in chilled ice. After centrifugation at +4°C, serum was separated and stored at -20°C.
The following results were obtained :
1) The sensitivity was of the order of ng or pg which enables quantitation with 2ml of human serum and urine sample.
2) The procedure is specific, sensitive, reproducible and rapid.
3) The use of GC-MS system to analyze hypophysiotropic releasing hormones enables us to elucidate the relative importance of these hormones and their metabolic changes in various physiological and pathological states of human beings.
