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Osmotic stress, plasma renin activity, and spermatogenesis in Vipera aspis.
No full textCirculating electrolytes (Na+, K+), plasmarenin-like activity, testosterone, and testis morphology were investigated in early summer during the spermatogenic progressive phase in Viperaaspis subjected to sodium loading and sodium depletion. After sodium loading, plasma sodium and plasma testosterone levels were significantly elevated compared with those of controls, while plasmarenin-like activity was depressed, spermiogenesis was increased, the epithelium lining the epididymis was very thick, and the Leydig cells were hypertrophied. After sodium depletion, plasma sodium and plasma testosterone levels were significantly depressed and plasmarenin-like activity was significantly elevated. Spermiogenesis seemed to be slightly regressed: the epithelium lining the epididymis was very thin, and the lumen was devoid of spermatozoa. The Leydig cells were hardly visible. All the data strongly suggest that osmoticstress affects gonadal activity in the snake. V. aspis
Intrarenal localization of angiotensin II specific binding in rat fetuses
No full textSpecific binding sites for angiotensin II were localized in the developing rat kidney (18th day of pregnancy and immediately before birth) by autoradiography using [125I]-ileu-5-angiotensin II either perfused in vivo through the fetal aorta or added in vitro to frozen sections in an incubation mixture. Specific binding was localized in the walls of the afferent and efferent arterioles, in the intraglomerular cells and in the peritubular arterioles of the subcapsular cortical zone. The immunohistochemical analysis, carried out on receptors saturated with unlabelled angiotensin II perfused through the mother's aorta, confirmed the autoradiographical localization. Antisera against ileu-5-angiotensin II were used in the indirect immunofluorescence technique and in the PAP method. Immunolocalization of angiotensin II was also found in the proximal tubule and in the thick ascending limb of Henle's loop
Angiotensin II vascular receptors in fetal and neonatal rats
No full textSpecific binding sites for angiotensin II in aorta and renal arteries have been studied in rat fetuses (18th day of pregnancy) and 1-day-old newborn rats by binding studies in arterial membranes using [125I] ileu-5-angiotensin II. One type of angiotensin receptor was found both in fetuses and in the newborns; the capacity of this (RT) decreased immediately after birth (from 0•06 ± 0•01 nM to 0•02 ± 0•005 nM; ± SEM) and the affinity (Kd) increased at birth (from 3•5 ± 0•6 nM to 19•5 ± 1•2 nM; ± SEM). Localization of the specific binding sites was studied by autoradiography on arteries from fetal and newborn rats either perfused with iodinated angiotensin II by cannulation of the aorta or in vitro on cryostat sections incubated with the radioactive angiotensin II. Both in fetuses and in the newborn the binding sites were located in the tunica media of the arteries
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