Cyclic nucleotide phosphodiesterases in somatic and germ cells of mouse seminiferous tubules

Abstract

Summary. The distribution of phosphodiesterase forms in somatic and germ cells, and their variations during testicular development and germ cell differentiation have been investigated. Seminiferous tubules from immature mice and Sertoli cells in culture possessed two enzyme activities which were comparable to forms described for different tissues and species: (a) a calcium\p=n-\calmodulin-dependentenzyme with high affinity for guanosine 3',5'-(cyclic)-monophosphate (cGMP), and (b) a calcium\p=n-\ calmodulin-independent enzyme with high affinity for adenosine 3' ,5' -(cyclic)\x=req-\ monophosphate (cAMP) the activity of which increased in cultured Sertoli cells after treatment with FSH or dibutyryl cAMP. Seminiferous tubules from adult animals and germ cells at the meiotic and post-meiotic stage of differentiation possessed two enzyme forms that could be distinguished from those present in somatic cells of the seminiferous tubules: (a) a calcium\p=n-\calmodulin-dependent form with high affinity for both cAMP and cGMP, similar to forms described in other tissues from different species, and (b) a calcium\p=n-\calmodulin-independentphosphodiesterase with high affinity for cAMP and present only in post-meiotic cells, previously identified also in germ cells of the rat.

Immunohistochemical localisation of PDE5 in Leydig and myoid cells of prepuberal and adult rat testis

“…Indeed, in these cells cGMP hydrolisis has been shown to occur in a calcium-calmodulin stimulated manner (Conti et al 1982;Rossi et al 1985;Conti et al 1995), which identifies this activity as due to a PDE1 family member. Enzymes of this family, though active towards both cAMP and cGMP, display a substantially higher affinity to the latter nucleotide (Zhao et al 1997).…”

Characterization by DEAE-Cellulose Chromatography of a Single Molecular Form of Cyclic Nucleotide Phosphodiesterase in the Myometrium of Nonpregnant Women

“…The question remains whether this form corresponds to a hor mone-regulated enzyme described in differ ent tissues (rat hepatocytes, somatic and ger minal cell of mouse seminiferous tubules, etc.) [19,20]. In humans, it is well known that pregnancy is associated with important hormonal modifications, among them a large impregnation of steroids in myome trium has been established clearly [21].…”

The Role of PDE5 Inhibitors in the Treatment of Testicular Dysfunction

“…Scipioni et al, (2005) could not detect any PDE5 expression in Sertoli cells in their experiments (Scipioni et al, 2005) suggesting that different PDEs are likely to contribute to the cGMP metabolism. Indeed, in Sertoli cells cGMP hydrolysis has been shown to occur in a calcium-calmodulin stimulated manner (Conti et al, 1982;Rossi et al, 1985;Conti et al, 1995) which identifies this hydrolytic activity as a result of a PDE1 family member. Enzymes of this family, though active towards both cAMP and cGMP, display a substantially higher affinity to the latter nucleotide (Zhao et al, 1997).…”