Evidence for a paracrine role of endogenous adrenomedullary galanin in the regulation of glucocorticoid secretion in the rat adrenal gland.

Previous investigations have shown that rat adrenocortical cells are provided with galanin receptors, and galanin stimulates glucocorticoid secretion from dispersed cells. The present study aimed to clarify the possible role of galanin in the physiological regulation of rat adrenal secretory activity. Reverse transcription-polymerase chain reaction detected galanin mRNA expression in the adrenal medulla, but not in the cortex.

Galanin enhances corticosterone secretion from dispersed rat adrenocortical cells through the activation of GAL-R1 and GAL-R2 receptors coupled to the adenylate cyclase-dependent signaling cascade.

Galanin is a regulatory peptide, which acts via three subtypes of receptors, named GAL-R1, GAL-R2 and GAL-R3. Reverse transcription-polymerase chain reaction demonstrated the expression of GAL-R1 and GAL-R2, but not GAL-R3 mRNAs in dispersed rat adrenal zona fasciculata-reticularis (inner) cells. The immuno-blockade of GAL-R1 and GAL-R2, but not GAL-R3, decreased the binding of [3H]galanin to dispersed cells, a complete inhibition being obtained only by the simultaneous blockade of both receptor subtypes.

Expression of osteoblast marker genes in rat calvarial osteoblast-like cells, and effects of the endocrine disrupters diphenylolpropane, benzophenone-3, resveratrol and silymarin.

Compelling evidence indicates that some endocrine disrupters (EDs), acting as selective estrogen-receptor modulators, interfere with osteoblast differentiation and function. Hence, we investigated whether four EDs [bisphenol-A (BSP), benzophenone-3 (BP3), resveratrol and silymarin] affect differentiation and growth of rat calvarial osteoblast-like (ROB) cells in primary in vitro culture. ROB cells were cultured for up 30 days in a medium supplemented with fetal calf serum (FCS), and conventional RT-PCR detected the expression of collagen-1alpha and osteonectin mRNAs through the entire culture period.

Effects of some endocrine disruptors on the secretory and proliferative activity of the regenerating rat adrenal cortex.

The effects of some endocrine disruptors that possess estrogen-like activity on the secretion and growth of regenerating rat adrenal cortex have been investigated in ovariectomized (OVX) and sham-OVX rats. As reference groups, dexamethasone (Dx)-administered sham-OVX and 17beta-estradiol-administered OVX animals were used. Dx, estradiol and endocrine disruptors were subcutaneously injected daily at a dose of 3 nmoles/100 g for 10 consecutive days after surgery, and adrenal enucleation was performed on day 5 of the experiment.

Accumulation of steroidogenic acute regulatory protein mRNA, and decrease in the secretory and proliferative activity of rat adrenocortical cells in the presence of proteasome inhibitors.

Sporadic findings indicate that proteolysis may affect steroid secretion in rat ovary granulosa cells. We examined the effects of the proteasome inhibitors MG115 and MG101 on the in vitro secretion and growth of rat adrenocortical cells. MG115 and/or MG101 decreased within 120 min the aldosterone and corticosterone secretion from freshly dispersed zona glomerulosa and zona fasciculata-reticularis (ZF/R) cells.