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181. Ultrastructural evidence for endogenous testosterone immunoreactivity in rat pituitary gland
Ixi
Abstracts 181.
ULTRASTRUCTURAL Morel, G., Forest, Facultd de Medecine
EVIDENCE
FOR ENDOGENOUS TESTOSTERONE IMMUNOREACTIVITY IN RAT PITUITARY GLAND d'Histologie, CNRS ERA 981, M.G.* and Dubois, P.M.-Laboratoire Lyon-Sud, Oullins, *INSERM U.34, HSpital Debrousse, Lyon, France.
(T) in its hypophysial With the aim of localizing endogenous testosterone level, an immunocytological technique was target cells at the ultrastructural performed on ultrathin slices obtained by cryoultramicrotomy. T immunoreactivity was detected in intact male and female rats in the gonadotropic cells only. At the was localized in the cytoplasmic matrix and subcellular level, the immunoreactivity 1) in rats after castration and in the nucleus. T immunoreactivity disappeared adrenalectomy ; 2) in rats injected with 25 ug of cyproterone6acetate ; 3) after preincubation of slices on a drop of cyproterone acetate (1 x 10 M). The immunoreactivity was not modified when rats were injected with estradiol, progesterone or of the slices with corticosterone corticos_tBerone (1 mg/rat) or after preincubation (1 x 10 M), or a buffer solution at pH : 7.6. Lower or higher values of pH provoke a strong decrease in the immunoreactivity. The injection of 5 pg T provokes the translocation of T from cytoplasm to the nucleus. These data suggest that T can be detected by immunocytochemistry. T is probably bound to a site which has the characteristics of the T receptor : cellular specificity, hormonal specificity and high affinity.
182. Potentiation by steroids of the effects of agents increasing CAMP content thymocytes S. Durant, D. Duval and F. Homo U7 INSERM, HCpital Necker, 161 rue de Sevres, 75015 Paris, France.
in isolated
There is increasing amount of evidence suggesting that glucocorticoids may modulate the responsiveness of various cell types to D-adrenergic agents. In some systems it has been shown in addition that steroid potentiate the elevation of CAMP induced by catecholamines. However, little is known of the mechanism underlying steroid action. We have studied this 'permissive action' in isolated thymocytes which have specific receptor sites for both glucocorticoids and R-adrenergic agents. Glucocorticoids did not alter intracellular CAMP level but markedly enhanced the stimulation produced by isoproterenol. This effect was instantaneous and was still measurable at lo-7M dexamethasone. A permissive effect of glucocorticoids was also seen in the presence of prostaglandin E2 which suggests that changes in D-receptors are not involved in this permissive action: this was confirmed by direct measurement of D-receptors after cell preincubation in the presence of dexamethasone. The data suggests that this effect of steroids is not, as previously believed, associated with an inhibition of phosphodiesterase activity but could be related to a modification of calcium mobilization.
183.
INTERSUBJECT Browning, Ninewells
VARIATION
IN THE EFFECT OF GLUCOCORTICOIDS
ON LYMPHOCYTE
GROWTH
M.C.K., Roberts, C., Potts, R., Brown, R. and Beck, J.S. Hospital, University of Dundee, Scotland.
It has previously been shown that there is a depression, by hydrocortisone in vitro PHA stimulation of lymphocytes and that it exhibits a log-dose relationship.
of the
Dose response curves using lymphocytes from normal subjects showed intersubject variation in the response. However, the degree of depression remained constant in each of six subjects studied on several occasions. Similar effects were found using prednisolone and betamethasone. This method appears to have the potential to determine the relative sensitivity of individual subjects to glucocorticoid therapy, thus possibly allowing treatment to be tailored to each patient's requirements.
Abstracts 181.
ULTRASTRUCTURAL Morel, G., Forest, Facultd de Medecine
EVIDENCE
FOR ENDOGENOUS TESTOSTERONE IMMUNOREACTIVITY IN RAT PITUITARY GLAND d'Histologie, CNRS ERA 981, M.G.* and Dubois, P.M.-Laboratoire Lyon-Sud, Oullins, *INSERM U.34, HSpital Debrousse, Lyon, France.
(T) in its hypophysial With the aim of localizing endogenous testosterone level, an immunocytological technique was target cells at the ultrastructural performed on ultrathin slices obtained by cryoultramicrotomy. T immunoreactivity was detected in intact male and female rats in the gonadotropic cells only. At the was localized in the cytoplasmic matrix and subcellular level, the immunoreactivity 1) in rats after castration and in the nucleus. T immunoreactivity disappeared adrenalectomy ; 2) in rats injected with 25 ug of cyproterone6acetate ; 3) after preincubation of slices on a drop of cyproterone acetate (1 x 10 M). The immunoreactivity was not modified when rats were injected with estradiol, progesterone or of the slices with corticosterone corticos_tBerone (1 mg/rat) or after preincubation (1 x 10 M), or a buffer solution at pH : 7.6. Lower or higher values of pH provoke a strong decrease in the immunoreactivity. The injection of 5 pg T provokes the translocation of T from cytoplasm to the nucleus. These data suggest that T can be detected by immunocytochemistry. T is probably bound to a site which has the characteristics of the T receptor : cellular specificity, hormonal specificity and high affinity.
182. Potentiation by steroids of the effects of agents increasing CAMP content thymocytes S. Durant, D. Duval and F. Homo U7 INSERM, HCpital Necker, 161 rue de Sevres, 75015 Paris, France.
in isolated
There is increasing amount of evidence suggesting that glucocorticoids may modulate the responsiveness of various cell types to D-adrenergic agents. In some systems it has been shown in addition that steroid potentiate the elevation of CAMP induced by catecholamines. However, little is known of the mechanism underlying steroid action. We have studied this 'permissive action' in isolated thymocytes which have specific receptor sites for both glucocorticoids and R-adrenergic agents. Glucocorticoids did not alter intracellular CAMP level but markedly enhanced the stimulation produced by isoproterenol. This effect was instantaneous and was still measurable at lo-7M dexamethasone. A permissive effect of glucocorticoids was also seen in the presence of prostaglandin E2 which suggests that changes in D-receptors are not involved in this permissive action: this was confirmed by direct measurement of D-receptors after cell preincubation in the presence of dexamethasone. The data suggests that this effect of steroids is not, as previously believed, associated with an inhibition of phosphodiesterase activity but could be related to a modification of calcium mobilization.
183.
INTERSUBJECT Browning, Ninewells
VARIATION
IN THE EFFECT OF GLUCOCORTICOIDS
ON LYMPHOCYTE
GROWTH
M.C.K., Roberts, C., Potts, R., Brown, R. and Beck, J.S. Hospital, University of Dundee, Scotland.
It has previously been shown that there is a depression, by hydrocortisone in vitro PHA stimulation of lymphocytes and that it exhibits a log-dose relationship.
of the
Dose response curves using lymphocytes from normal subjects showed intersubject variation in the response. However, the degree of depression remained constant in each of six subjects studied on several occasions. Similar effects were found using prednisolone and betamethasone. This method appears to have the potential to determine the relative sensitivity of individual subjects to glucocorticoid therapy, thus possibly allowing treatment to be tailored to each patient's requirements.