Role of the sympathetic nervous system in the control of the goitrogenic response in the rat
The role of the sympathetic nervous system in the control of the goitrogenic response was examined in adult male rats subjected to superior cervical ganglionectomy (SCGx) 7 days earlier. In the first experiment, superior cervical ganglionectomized (SCGx) or sham-operated animals were treated with th...
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1981
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00137227_v109_n6_p2202_Pisarev http://hdl.handle.net/20.500.12110/paper_00137227_v109_n6_p2202_Pisarev |
| Aporte de: |
| Sumario: | The role of the sympathetic nervous system in the control of the goitrogenic response was examined in adult male rats subjected to superior cervical ganglionectomy (SCGx) 7 days earlier. In the first experiment, superior cervical ganglionectomized (SCGx) or sham-operated animals were treated with the goitrogenic agent methylmercaptoimidazole (MMI) for 4 days, and their thyroid weights and plasma TSH levels were measured. After MMI administration, the increase in thyroid weight was significantly greater in SCGx than in sham-operated rats. The plasma TSH increases after MMI were similar in both groups. To rule out the possible involvement of the pineal gland, MMI treatment was carried out in rats subjected to pinealectomy or sham pinealectomy 7 days earlier. Thyroid weights and plasma TSH levels after pinealectomy were not different from controls in vehicle- or MMI-treated rats. In a third experiment, the goitrogenic response to TSH was assessed in SCGx or shamoperated rats; the thyroid weight of SCGx animals increased by 72% after TSH treatment compared to a 35% increase in the controls (P < 0.01). Seven days after SCGx [3H]uridine incorporation into thyroid RNA increased significantly by 64%, and 4 weeks after SCGx, spontaneous goiter developed. Blood flow, estimated from the uptake of a tracer dose of 86Rb, decreased significantly in the thyroid and pineal gland after SCGx. Norepinephrine and epinephrine levels in the thyroid gland were depressed 70-80% within 24 h after SCGx, whereas dopamine levels remained unaltered. An increase in the number of aadrenoceptor sites, assessed by [3H]dihydroergocryptine binding to thyroid membranes, was found in SCGx rats, while the β- adrenoceptors (assessed by [3H]dihydroalprenolol binding) did not change. The results suggest that the cervical Sympathetics normally exert a negative influence on thyroid function in the rat. (Endocrinology 109: 2202, 1981). © 1981 by The Endocrine Society. |
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