[Immunochemical method of determining the biosynthesis of hypophyseal hormones. Effect of liberins and cyclic AMP on the biosynthesis of luteinizing hormone, prolactin and growth hormone in the rat pituitary].

A simple procedure is developed, which enables to estimate sequentially the biosynthesis of luteinizing hormone (LH), prolactin (LTH) and somatotropic hormone (STH) in rat hypophysis using solid-phase immunosorbents prepared on the basis of antisera to the hormones studied, copolymerized with chlorcarbonic acid isobutyl ester. The immunosorbents exhibited high specificity and pronounced immunosorption capacity. The analysis was carried out as follows: incubation of hypophyses with 14C-lysine in vitro, chromatography of the hypophysis extracts on columns with Sephadex G-25 and immunosorption of hormones. Within 4 hrs of incubation the biosynthetic processes in hypophysis were distinctly increased, reaching maximal values between 4 hrs and 6 hrs of incubation. Biosynthesis of LH and LTH in adult females exceeded 2-fold the STH biosynthesis and in 23 days old female rats the STH biosynthesis was more than 1.5- and 3-times higher than that LH and LTH synthesis. Luliberin at a dose 1.5 X 10(-6) M/hypophysis stimulated biosynthesis of LH, inhibited LTH biosynthesis but did not affect the STH synthesis in vitro. Thyroliberin (3.0 X 10(-6) M/hypophysis) stimulated LTH and STH biosynthesis and did not affect the LH synthesis. Dibutyryl-cAMP (0.5 X 10(-3) M/hypophysis) stimulated biosynthesis of all these hormones.