ABSTRACT
The effect of a single dose (5mg/kg b.w.) of diazepam on the cell proliferation in selected organs of 11-day old female Sprague-Dawley rats has been investigated. The stathmokinetic method (counting of mitoses after colchicine administration) has been used for evaluation of cell replication. The significant fall of the mitotic activity in the parietal cerebral cortex and the anterior pituitary gland was found. On the other hand, the increase of the mitotic activity in thymus was observed. The reported data, taken together with the previous observations from our and other laboratories, suggest the involvement of benzodiazepine receptor in the control of cell proliferation.
Subject(s)
Cerebral Cortex/cytology , Diazepam/pharmacology , Pituitary Gland, Anterior/cytology , Thymus Gland/cytology , Animals , Cell Division/drug effects , Female , Mitosis/drug effects , Rats , Rats, Inbred StrainsABSTRACT
Influence of thyrotropin (TSH) on colloid droplet formation in thyroid follicular cells and on release of a stable prostacyclin metabolite, 6-keto-prostaglandin 1 alpha (6-keto-PGF 1 alpha) from the thyroid has been studied in rats. Maximal accumulation of colloid droplets preceded the enhancement of the 6-keto-PGF 1 alpha release. Such a time sequence speaks against the possibility of prostacyclin involvement in the thyroid secretory response to TSH.
Subject(s)
6-Ketoprostaglandin F1 alpha/metabolism , Thyroid Gland/drug effects , Thyrotropin/pharmacology , Animals , Colloids/metabolism , Male , Rats , Rats, Inbred Strains , Thyroid Gland/metabolismSubject(s)
Pineal Gland/surgery , Pituitary Gland, Anterior/cytology , Adult , Animals , Humans , Male , Mitosis , Rats , Rats, Inbred StrainsABSTRACT
An influence of thyrotropin (TSH), dibutyryl cyclic AMP (dbcAMP), triiodothyronine (T3) and thyroxine (T4) on the mitotic incidence in the organ-cultured rat thyroid was studied. The study has revealed biphasic inhibitory and stimulatory effects of TSH on the thyroid mitotic activity. The inhibitory effect occurred 14 h after an exposure of the thyroid explants to TSH and was enhanced by T3. A similar inhibitory effect was observed after an exposure of the explants to dbcAMP. 24 h after the exposure of the thyroid explants to TSH a stimulatory effect on the mitotic incidence was observed. The latter effect was not reproduced by dbcAMP.
