[The dynamics of changes in the concentration of luteinizing hormone in the pituitary and the blood during postnatal development of male rats].

The authors describe a specific and sensitive biological method of determination of luteinizing hormone (LH). There was shown a linear relationship between the LH dose gradient and the amount of testosterone determined in the blood flowing from the testes. Sensitivity of the method--5 nanogram/ml. Linear dependence--5--45 nanogram/ml. Dynamics of the changes in the LH concentration in the hypophysis and the blood of male rats in the course of postnatal development--from the 1st to the 43rd day was studied. There were distinguished 6 peaks of increase in the LH content in the hypophysis: on the 4th, 7th, 19th, 27th, 37th and the 43rd day after birth; blood LH concentration persisted at a relatively constant level--within the range of 1.33--4.39 gamma per cent. No LH was revealed in the blood on the 4th, 19th, and 24th days after birth.