| Abstract: | In the rat olfactory tissue the existence of soluble and membrane-bound forms of cyclic nucleotide phosphodiesterase (PDE) with quite similar kinetic parameters was demonstrated (KM = 220 and 200 microM, VMaX = 10 and 7 nmoles cAMP/mg protein per minute, respectively). 17 beta-estradiol (10(-7)-10(-5) M) decreased the soluble PDE activity by 25%, whereas non-hydrolysable GTP analogue (Gpp (NHp)) abolished their effect. On the other hand, this analogue in a dose-dependent manner inhibited the specific binding of 3H-estradiol to cytosolic receptors. The data indicate possible functional interrelations between the cytosolic estradiol receptors, GTP-binding proteins and PDE in the olfactory tissue which is a target organ for steroid hormones. |
