Identification by gas chromatography and mass spectrometry of 1-monoglycerides in European hamster brown adipose tissue and plasma.

1. In organ culture, brown adipose tissue of the hibernator, the European hamster, synthezises from [14C]acetate a compound which is secreted into the culture medium. 2. Gas chromatographic-mass spectrometric analysis of samples, extracted from brown adipose tissue and corresponding to that unknown radioactive compound, used as a marker, lead to the identification of the two major components as 1-monoglycerides: 1-monopalmitin and 1-monoolein. 3. The two 1-monoglycerides are also present in the blood plasma and are not of alimentary origin. 4. The problem of the significance of 1-monoglycerides in brown adipose tissue and plasma is discussed in connexion with the postulated indirect role of brown adipose tissue in thermogenic processes.