García-López MJ, Martínez-Martos JM, Mayas MD, Carrera MP, Ramírez-Expósito MJ

Language: English
References: 25
Page: 4-10
PDF size: 476.18 Kb.

ABSTRACT

The hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the regulation of blood pressure. In the present work, we analyze the effects of ovariectomy and estradiol (E) replacement on several soluble (s) and membrane bound (b) aminopeptidases involved in the regulation of the renin-angiotensin system (RAS) (aminopeptidase A (APA), aminopeptidase M (APM) and aminopeptidase B (APB)) and vasopressin-degrading activity (AVP-DA) in HPA axis. Fifty female mice (Balb/C) were distributed in five groups: Sham-operated control (C), ovariectomized (OV-C) and ovariectomized treated with (10, 20 and 40 mg/Kg) E. In hypothalamus, APAs and APAb increased after ovariectomy while E replacement return the activitiy to the control levels. On the contrary, neither ovariectomy nor E replacement modified pituitary APAs and APAb. In adrenal, APAs did not change after ovariectomy, but the highest dose of E increased this activity. However, APAb increased in adrenal after ovariectomy, whereas E replacement return the activity to control levels. APMs and APBs did not change neither after ovariectomy nor E replacement in hypothalamus. In the same way, APMb did not change after ovariectomy, but the highest dose of E increased it. APBb increased after ovariectomy but return to control values after E administration. In pituitary, neither ovariectomy nor E replacement modifies APMb and APBb. However, ovariectomy increased APBs but not APMs. E replacement return APBs to control levels, and the lowest dose of E decreased APMs. In adrenal,ovariectomy did not change APMs and APBs, but E replacement decreased both activities. Ovariectomy increased APMb and APBb and E replacement only return APBb to control levels. AVP-DAs did not change neither after ovariectomy nor E replacement in the HPAaxis. On the contrary, AVP-DAb increased after ovariectomy only in hypothalamus, and E replacement return the values to control levels. Only pituitary AVP-DAb increased with the highest dose of E used. Due to the role of these aminopeptidases on the systemic and local renin angiotens in systems, hormonal modifications during physiological and/or pathological conditions could modify blood pressure regulation through these systems.

REFERENCES

1. Kon Y. Local renin-angiotensin system: specially in coagulating glands of mice. Arch Histol Cytol 1996; 59:399-420.

2. Vila-Porcile E, Corvol P. Angiotensinogen, prorenin and renin are co-localized in the secretory granules of all glandullar cells of the rat anterior pituitary: an inmunoultrastructural study. J Histochem Cytochem 1998; 46:301-11.

3. Wright JW, Krebs LT, Stobb JW, Harding JW. The angiotensin IV system: functional implications. Front Neuroendocrinol 1995; 16:23-52.

4. Chansel D, Ardaillou R. Active metabolites dereved from angiotensin II. Nephrologie 1998; 19:427-32.

5. McDonald J K, Barret AJ. Mammalian proteses. A glossary and bibliography. Volume 2. Exopeptidases. London: Academic Press. 1986.

6. Ward PE, Benter IF, Dick L, Wilks L. Metabolism of vasoactive peptides by plasma and purified renal aminopeptidase M. Biochem Pharmacol 1990; 40: 1725-32.

7. Ardaillou R. Active fragments of Ang II: enzymatic pathways of synthesis and biological effects. Curr Opin Nephrol Hypertnes 1997; 6:28-34.

8. Szczepanska-Sadowska E. Interaction of vasopressin and Ang II in the central control of blood pressure and thrist. Regul Pept 1996; 66:65-71.

9. Martínez JM, Prieto I, Ramírez MJ, Alba F, Ramírez M. Cholesterol and steroid action on aminopeptidases. Biochem Soc Trans 1997;25:113S.

10. Martínez JM, Ramírez MJ, Prieto I, Alba F, Ramírez M. Sex differences and in vitro effects of steroid on serum aminopeptidase activity. Peptides 1998;19:1637-40.

11. Cheung HS, Cushman DW. A soluble aspartate aminopeptidase from dog kidney. Biochim Biophys Acta 1971; 242:190-3.

12. Tobe H, Kojima FJ, Aoyagi T. Purification by affinity chromatography using amastatin and properties of aminopeptidase A form pig kidney. Biochim Biophys Acta 1980; 613:459-68.

13. Greenberg LJ. Fluorometric measurement of alkaline phosphatase and aminopeptidase activities in the order of 1014 mole. Biochem Biophys Res Commun 1962; 9: 430-5.

14. Schnebli HP, Phillipps MA, Barclay RK. Isolation and characterization of an enkephalin-degrading aminopeptidase from rat brain. Biochim Biophys Acta 1979; 569:89-98.

15. Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of proteindye binding. Anal Biochem 1976; 72: 248-54.

16. Krishnamurthi K, Verbalis JG, Zheng W, Ku Z, Clerch LB, Sandberg K. Estrogen regulates angiotensin I receptor expression via cytosolic proteins that bind to the 5' leader sequence of the receptor mRNA. Endocrinology 1999;140:5435-8.

17. Kisley LR, Sakai RR, Fluharty SJ. Estrogen decreases hypothalamic angiotensin II AT1 receptor binding and mRNA in the female rat. Brain Res 1999; 844:34-42.

18. Mosca L, Manson JE, Sutherland SE, Langer RD, Manolio T, Barrett-Connor E. Cardiovascular disease in women: a statement for healthcare professionals from the American Heart Association. Writing Group Circulation 1997; 96:2468-82.

19. Roesch DM, Tian Y, Zheng W, Shi M, Verbalis JG, Sandberg K. Estradiol attenuates angiotensin-induced aldosterone secretion in ovariectomized rats. Endocrinology 2000; 141: 4629-36.

20. Seely EW, Walsh BW, Gerhard MD, Williams GH. Estradiol with or without progesterone and ambulatory blood pressure in postmenopausal women. Hypertension 1999; 33:1190-4.

21. Calogero AE, Fornito MC, Aliffi A, Vicari E, Moncada ML, Mantero F, et al. Role of peripherically infused angiotensin II on the human hypothalamic-pituitary-adrenal axis. Clin Endocrinol (Oxf) 1991; 34:183-6.

22. Jezova D, Ochedalski T, Kiss A, Aguilera G. Brain angiotensin II modulates sympathoadrenal and hypothalamic pituitary adrenocortical activation during stress. J Neuroendocrinol 1998; 10:67-72.

23. Zini S, Masdehors P, Lenkei Z, Fournier-Zaluski MC, Roques BP, Corvol P, et al. Aminopeptidase A: distribution in rat brain nuclei and increased activity in spontaneously hypertensive rats. Neuroscience 1997; 78:1187-93.

24. Lenkey Z, Palkovits M, Corvol P, Llorens-Cortes C. Expression of angiotensin type-1 (AT1) receptor mRNAs in the adult rat brain: a functional neuroanatomical review. Front Neuroendocrinol 1997; 18:383-439.

25. Itoh C, Nagamatsu A. An aminopeptidase activity from porcine kidney that hydrolyzes oxitocin and vasopressin: purification and partial characterization. Biochim Biophys Acta 1995; 1234:203-8.