The present study was undertaken to evaluate the state of glucocorticoid cytosol receptor binding in muscle hypertrophied by compensatory overload in normal, testosterone-treated, and castrated male rats. Compensatory hypertrophy in plantaris muscles was induced by myomectomy of the gastrocnemius and the soleus of 100 male Sprague-Dawley rats. The controlateral sham-operated limb was used as control. The rats were divided in 3 groups: control injected with peanut oil, castrated injected with peanut oil, and castrated injected with testosterone propionate (1 mg/rat). Five days later the animals were sacrificed and the muscles obtained for glucocorticoid receptor binding studies using [3H]dexamethasone as ligand. Receptor concentrations (Bmax) were significantly increased in hypertrophied muscle and the increase was not affected either by castration or by androgen treatment. These results tend to suggest that gonadal steroids do not participate in hypertrophy-induced proliferation of glucocorticoid receptors.

Androgens↗

PubMedDate not supplied

Distribution of annexin I and II in term human fetal membranes, decidua and placenta.

Annexin I and II are calcium binding proteins implicated in the regulation of a number of cellular functions, including secretory processes, prolactin release and prostaglandin formation. The cellular distribution of these proteins was examined in human term placenta, fetal membranes (amnion and chorion laeve) and decidua using immunohistochemistry. Annexin I was found in amnion epithelial cells and chorion laeve trophoblast but not in decidua, and was located in the syncytiotrophoblast cells of placenta. Annexin II and annexin II light-chain were located in the amnion epithelial cells, the cells of the mesenchymal layer between the amnion and chorion laeve trophoblast and endothelial cells lining the blood vessels in the decidua. In contrast to annexin I, annexin II was located in the villous core and not the syncytiotrophoblast cells in the placenta. There was no apparent change in the distribution of these annexins during labour. These findings indicate that the cellular distribution of these annexins is different, and may be an important consideration when examining their synthesis or action in tissues and in vitro with mixed cell populations and tissue homogenates.

Annexin A1↗

PubMedDate not supplied

Temporal expression of prostaglandin H synthase type 2 (PGHS-2) and P450(C17)in ovine placentomes with the natural onset of labour.

Labour in the sheep is preceded by increased tissue and plasma prostaglandin (PG) concentrations, and PGs could potentially contribute to the regulation of P450(C17)in placental tissue. Therefore, we determined the cellular localization and temporal pattern of expression of P450(C17)and prostaglandin H synthase type 2 (PGHS-2), the primary PG synthetic enzyme, in intrauterine tissues from three groups of pregnant ewes at term; animals not in labour (NIL;n=5; 140-145 days of gestation), animals in early labour (EL;n=6; 143-149 days) and animals in active labour (L;n=6; 145-149 days). Allocation of animals into the three groups was based on continuous monitoring and assessment of myometrial contractile activity (EMG) and changes in the intrauterine pressure (IUP). Levels of mRNA encoding PGHS-2 and P450C17 were determined by in situ hybridization. Localization and levels of immunoreactive (ir-) P450(C17)and ir-PGHS-2 protein were determined by immunohistochemistry and Western blotting. PGHS-2 mRNA and ir-PGHS-2 were already elevated in placentomes of NIL animals and did not increase further with the progression of labour, whereas P450C17 mRNA increased progressively with labour, and ir-P450C17 rose significantly only in animals in active labour. The rise in P450C17 expression corresponded temporally to a progressive increase in maternal plasma concentration of oestradiol. We suggest that the temporal relationship and subsequent co-localization of PGHS-2 and P450(C17)proteins in the uninucleate trophoblast cells of the placentomes are consistent with the possibility that placental PGs could act to enhance placental output of oestrogen leading to labour and delivery.

Animals↗