PARATHYROID CROSS-TRANSPLANTATION AND DEVELOPMENT OF HIGH BLOOD-PRESSURE IN RATS

To clarify further the relationships between parathyroid glands and th e development of hypertension, we studied the effect of cross-transpla ntation of these glands from young hypertensive rats in normotensive r ecipients. The parathyroid glands were isolated in 5-week-old hyperten sive rats of the Lyon (male and female) and Milan (only male) strains and immediately grafted into the corresponding, just parathyroidectomi zed normotensive rats of the same age. Control rats were either sham-o perated or grafted with the glands of the same normotensive strain. Pl asma calcium concentration immediately decreased after parathyroidecto my (PTX) and returned to near normal values 3 weeks after the graft. S ystolic blood pressure increased slightly, but significantly, in normo tensive animals grafted with hypertensive glands compared with that in normotensive control rats (mean increase, +9 mm Hg in males; +5 mm Hg in females). In conclusion, parathyroid gland transplantation from th e hypertensive strain is able to chronically enhance blood pressure in the normotensive animal. The parathyroid hypertensive factor recently described may be implicated in these two hypertensive strains. Our da ta extend observations obtained previously in SHRs and stroke-prone SH Rs and add further evidence for a major function of parathyroid glands in experimental hypertension.