Effects of TRH and TRH-like peptide pGLU-HIS-GLY-NH(2) on adrenocortical cell proliferation in rats.

The effects of three peptides-colon mitosis inhibitor (CMI), its amide, and thyroliberin (TRH)-on the adrenocortical cell proliferation were studied. As an index of cell proliferation, the incorporation of bromodeoxyuridine (BrDU) into adrenocortical cell nuclei was used. It was found that: Twelve hours after the injection, only CMI-amide significantly increased the total number of BrDU-immunopositive cell nuclei per equatorial section of the adrenal cortex. This mitogenic effect was observed separately for the entire section, zona glomerulosa, and zona fasciculata. TRH stimulated the cell proliferation of the adrenal cortex 24 h after the injection. Its mitogenic effect was observed for entire section and zona glomerulosa. These findings suggest that these two related peptides, TRH and CMI-amide, should be considered as growth factors for the adrenal cortex.

Influence of interleukin 1 and antihuman interleukin 1 receptor antibody on the growth and function of the thyroid gland in rats.

Cytokines seem to influence the hypothalamo-pituitary-thyroid axis. We have studied the effect of different doses of interleukin 1 alpha (IL-1 alpha) and IL-1 beta (given twice daily ip) alone or together with antihuman IL-1 receptor antibody (aIL-1ra) on the proliferation of thyroid follicular cells and thyroid hormone levels in male Wistar rats. We have examined the influence of IL-1 alpha and IL-1 beta at doses of 10.0, 1.0 and 0.1 micrograms/kg body wt of animal and aIL-1ra at a dose of 10.0 micrograms/kg body wt of animals. The incorporation of bromodeoxyuridine into thyroid follicular cell nuclei was used as an index of cell proliferation (labeling index: LI) and measured 24 h after the last of two injections of interleukin. Interleukin 1 beta, at all examined doses, increased thyroid follicular cell proliferation when compared to controls (p < 0.05), and a positive correlation between log of the dose of IL-1 beta used and LI (r = 0.62, p < 0.05) using Student's t-test was found. The administration of aIL-1ra alone also enhanced the thyroid follicular cell proliferation, whereas aIL-1ra used together with IL-1 beta exerted a less pronounced effect than each of these substances used separately (p < 0.05). Interleukin 1 alpha at the dose of 10.0 micrograms/kg body wt increased the proliferation of thyroid follicular cells (p < 0.05). Thyroid hormone levels did not change in any of the experiments. These results suggest a regulatory role of IL-1 upon the proliferation of thyroid cells.

Interleukin-1 beta stimulates cell proliferation in the intermediate lobe of the rat pituitary gland.

Interleukin-1 (IL-1) is a multifunctional monokine which possesses an impressive array of diverse actions relating to the function of the immune system. IL-1 is present and formed locally in the brain as demonstrated by biochemical and immunocytochemical methods. Various immunomodulatory and neuroendocrine effects of IL-1 have been reported, including induction of several morphological changes in the endocrine cells of experimental animals and humans. IL-1 is present in two molecular forms (IL-1 alpha and IL-1 beta) that activate specific receptors for IL-1. In the present study we investigated the possible effect of recombinant human IL-1 alpha and IL-1 beta and recently cloned anti-human IL-1 receptor antibody (M10) on cell proliferation in the anterior and the intermediate lobe of the pituitary gland of the rat. In vivo labelling with bromodeoxyuridine (BrdU) and immunocytochemical staining with anti-BrdU monoclonal antibody were used as a sensitive index of cell proliferation. IL-1 beta was found to stimulate dose-dependently (0.1-10 micrograms/kg body weight) incorporation of BrdU into pituitary intermediate cell nuclei, and positive correlation between the tested doses of IL-1 beta and BrdU-labelling index was noted (r = 0.89; P < 0.01). This IL-1 beta-induced stimulation of pituitary pars intermedia cell proliferation was receptor specific, since stimulation was blocked by anti-IL-1 receptor antibody. On the other hand, recombinant human IL-1 alpha did not affect BrdU incorporation and the proliferation of pituitary pars intermedia cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of new somatostatin analogs on the cell proliferation of colonic crypts and colonic cancers in rats.

The antiproliferative activity of two new somatostatin (SS) analogs: ASS-51 and ASS-52 have been tested in this study. We assessed their ability to inhibit the DNA synthesis in normal colon crypt cells and in the cells of chemically (dimethylhydrazine)-induced colon cancer in the rats. The incorporation of bromodeoxyuridine (BrDU) into appropriate cell nuclei was used as an index of DNA synthesis. It was found that: 1) Only ASS-51 significantly decreases the colon crypt cell proliferation in the rat when compared to controls. Since both analogs were previously shown to inhibit GH release, these data indicate that the antiproliferogenic effect of ASS-51 is independent of the inhibition of GH release. 2) Both examined analogs did not significantly effect the BrDU incorporation into cell nuclei of chemically-induced colon cancer.

Comparison of the antiproliferative effects of colon mitosis inhibitor, thyroliberin and the somatostatin analog octreotide on rat colonic mucosal epithelial cells.

The effects of colon mitosis inhibitor (CMI), thyroliberin (TRH), and the somatostatin analogue octreotide (SMS 201-995) on rat colonic mucosal epithelial cell proliferation were studied. As an index of cell proliferation the incorporation of bromodeoxyuridine (BrDU) into cell nuclei was used. It was found that all three peptides inhibited the colonic mucosal epithelial cells proliferation, but the time course of inhibition was different. The effect of SMS 201-995 occurred 12 h after the peptide injection, while CMI and TRH suppressed the proliferation after 24 h. These observations suggest that the mechanisms of the antiproliferative actions of somatostatin and of related tripeptides CMI and TRH are different.

Failure of tripeptide colon mitosis inhibitor to suppress the cell proliferation of dimethylhydrazine-induced colonic cancers in rats.

The effects of tripeptide colon mitosis inhibitor (CMI, pGlu-His-Gly-OH) on the proliferation of tumoral cells of dimethylhydrazine (DMH)-induced colonic cancers in rats were studied. Additionally, the effects of CMI on hyperplastic colonic crypts in DMH-treated rats and on normal colonic crypts in carcinogen-untreated rats were estimated. As an index of the cell proliferation the incorporation of bromodeoxyuridine (BrDU) into cell nuclei was used. It was found that the tripeptide significantly suppressed the proliferation of the colonic crypts in normal, carcinogen-untreated rats. However, it failed to suppress the cell proliferation of DMH-induced colonic adenocarcinomas or adenomas and produced only a slight, statistically insignificant decrease of the BrDU labelling index in hyperplastic colonic mucosa of DMH-treated rats. These findings suggest that the process of carcinogenesis might 'switch off' the local negative control of the colonic cell proliferation exerted by endogenous CMI.

Thyroliberin (TRH) increases thymus cell proliferation in rats.

The effects of thyroliberin (TRH), a TRH-like tripeptide colon mitosis inhibitor (CMI), a somatostatin analog SMS 201-995 and metoclopramide (dopamine receptor antagonist enhancing prolactin secretion) on rat thymus cell proliferation were investigated. The incorporation of bromodeoxyuridine (BrDU) into thymic cell nuclei was used as an index of the proliferation. It was found that TRH, but not other compounds investigated herein, increased the thymus cell proliferation 12 hours after the injection.

Chronic metoclopramide treatment stimulates T lymphocyte proliferation in the spleen but not in the thymus.

The effect of chronic metoclopramide administration (for 10 days at a daily dose of 5 mg/kg body weight subcutaneously) on cell proliferation in spleen and in thymus was investigated. Cell proliferation was evaluated by the stathmokinetic method with the use of vincristine. It was found that metoclopramide administration results in a statistically significant increase in the value of the mean mitotic activity rate index (MMAR) of splenocytes in the areas around arteries. At the same time no statistically significant changes were demonstrated in the MMAR index values obtained for splenocytes present in the germinal centers of the spleen. No significant changes in the MMAR index could also be found for thymocytes.

Inhibitory effect of bombesin and SMS 201-995 on DNA synthesis in the rat thyroid lobes incubated in vitro.

The effects of 4-h incubation in the presence of bombesin on the incorporation of [3H]-thymidine into DNA of the rat thyroid lobes, collected from animals treated in vivo with a long-acting somatostatin analog (SMS 201-995) or with 0.9% NaCl, were investigated. It was shown that not only in vivo injections of SMS 201-995, but also, unexpectedly, in vitro incubation with bombesin inhibited [3H]-thymidine incorporation. The two examined substances did not reveal any additive action in their inhibitory effects on the thyroid growth.

Inhibitory effect of porphyrins on the proliferation of mouse spleen lymphocytes in vitro.

The influence of various porphyrins (deuteroporphyrin IX, mesoporphyrin IX, protoporphyrin IX, hematoporphyrin) and two related compounds (hemin, biliverdin) on the spontaneous proliferation of mouse spleen lymphocytes has been estimated in vitro by the 3H-thymidine uptake assay. It has been found that porphyrins (endogenous ligands for the mitochondrial benzodiazepine receptor) produce a concentration-dependent inhibition of 3H-thymidine incorporation into the DNA of these cells. Metalloporphyrin-hemin has been observed to evoke a weak inhibitory effect, in a high concentration (10(-4)M), whereas biliverdin, a porphyrins degradation product, was inactive in the same experimental conditions. Those findings indicate that endogenous porphyrins, presumably acting through the mitochondrial benzodiazepine receptor, could regulate the proliferation of mouse spleen lymphocytes in vitro.

Effects of metoclopramide on rat spleen lymphocyte proliferation.

The effect of metoclopramide on proliferation of spleen lymphocytes in rats was examined. The rate of [3H]thymidine incorporation into DNA was used as an index of lymphocytes proliferation. It was shown that the incorporation of [3H]thymidine into DNA of spleen lymphocytes in the rats treated with metoclopramide was significantly higher than that in the control group. The effects of various concentrations of prolactin and metoclopramide on [3H]thymidine uptake by DNA of spleen lymphocytes was also studied in vitro. It was shown that: 1, Prolactin, at the concentration of 1 and 0.1 ng/ml significantly increased [3H]thymidine incorporation into DNA of spleen lymphocytes. Metoclopramide in all the examined concentrations also caused a significant proliferogenic effect on lymphocytes.

Influence of somatostatin and epidermal growth factor (EGF) on the proliferation of thyroid follicular cells in organ culture.

The aim of the present study has been to examine the effects of various concentrations of somatostatin (SS), epidermal growth factor (EGF), as well as of interactions among SS, EGF and thyrotropin (TSH) in their influence upon the mitotic activity of thyroid follicular cells (TFC) in organ culture. The stathmokinetic method was employed. It was shown that: (1) SS, at the concentration of 10(-7) M, suppressed the mitogenic effect of TSH, as well as of TSH and EGF employed together, on TFC; (2) EGF, at the concentration of 10 and 100 ng/ml, increased the mean mitotic activity rate of TFC; (3) TSH and EGF revealed an additive action on TFC proliferation. The obtained results evidently suggest an antiproliferative effect of SS and mitogenic action of EGF on TFC in organ culture.

Hydrocortisone inhibits the basal and angiotensin II-stimulated proliferation of rat adrenocortical cells in organ culture.

The present study has been to test the effect of hydrocortisone (HC) on the mitotic incidence in adrenocortical cells of organ-cultured rat adrenal explants during a 24-hour incubation with or without angiotensin II (ANG). It was shown that HC significantly decreased the mean mitotic activity rate (MMAR) of adrenocortical cells in organ culture. That decrease concerned all the three cortical zone vs respective controls. In turn, ANG markedly increased the MMAR of the zona glomerulosa cells, when compared to the values recorded in controls, while there were no changes of the MMAR of the zona glomerulosa in the adrenal explants incubated with joint exposure to HC and ANG. The obtained results indicate that HC exhibits an inhibitory effect on the adrenocortical cell proliferation, which may suggest that arachidonic acid metabolites play an important role in the process of adrenocortical hyperplasia, their participation in the ANG-induced zona glomerulosa cell proliferation being strongly assumed.

[Abnormalities of structure and function of the thyroid in patients with alopecia areata]. / Nieprawidlowosci budowy i czynnosci gruczolu tarczowego u chorych z lysieniem plackowatym.

In 85 patients with alopecia areata the frequency of thyroid disease was assessed on the basis of history data, clinical examination and determination of T3, T4, TSH and presence of antithyroid antibodies of different specificity (ATMA, ATg, AMD). Among these patients abnormalities of thyroid structure and function were significantly more frequent (78%) than in the control group (33%). In 11% of the patients autoimmune thyroid disease was present (Graves-Basdow disease, Hashimoto thyroiditis). In 86 controls no cases of autoimmune diseases were found. In some patients only a slight enlargement of the thyroid was present (grade OB, I.).

Suppressing effect of cysteamine on the TSH-stimulated mitotic activity of the rat thyroid follicular cells in vivo.

We have examined the effect of the thiol agent-cysteamine, known to deplete the hypothalamus, the pancreas, the gut of somatostatin--on the basal and TSH-stimulated mitotic activity of the thyroid follicular cells (TFC) in adult male rats in vivo. The animals of different groups were administered cysteamine alone (300 mg/kg BW, s.c.), TSH alone (2IU, i.p.), or cysteamine with TSH jointly, the former agent being injected 2 hrs prior to the latter. In order to evaluate the thyroid mitotic activity, the metaphase-arrest technique was used in the study. It was shown that: 1. TSH significantly increased the mitotic activity of TFC, as compared to controls, 2. cysteamine alone had no effect on the TFC proliferation, 3. unexpectedly, cysteamine, when administered 2 hrs prior to TSH, suppressed the stimulatory effect of TSH on the mitotic activity of TFC.

Influence of melatonin and N-acetylserotonin on the cyclic AMP concentration in the rat thyroid lobes incubated in vitro.

Effects of melatonin and N-acetylserotonin on the cyclic AMP (cAMP) concentration in the organ-cultured rat thyroid gland were investigated. Exposure of the thyroid explants to melatonin (10(-8) M) resulted in a decrease of cAMP levels. Melatonin at higher concentrations (10(-7) M and/or 10(-6) M) failed to influence the thyroid cAMP level. N-acetylserotonin (10(-6) M), like melatonin in the lowest concentration employed, reduced cAMP concentrations in the thyroid explants when compared with controls. Unexpectedly, melatonin (at a concentration of 10(-7) M) added to the incubation medium with TSH (60 mU/ml), decreased the cAMP concentration in the thyroid compared with the group exposed to melatonin (10(-7) M) alone.

Melatonin-induced suppression of human lymphocyte natural killer activity in vitro.

One of the important immune functions influenced by neuroendocrine factors is natural killer (NK) activity, which is directed against neoplastic and virus-infected cells. The effects of melatonin (Mel) and N-acetylserotonin (NAc-5HT) on NK activity of human peripheral blood lymphocytes were investigated. Leukocytes of healthy human subjects were used in the experiment. NK activity was estimated by measurement of radioactive chromium (51Cr) release from human leukemia cells K 562 (target cells). The previous exposure of human lymphocytes (effector cells) to Mel in concentrations of 10(-6) M and 10(-10) M resulted in an inhibition of NK activity (P less than 0.01) for all the examined effector-target cell ratios (10:1; 20:1, 40:1). NK activity was also suppressed by Mel (10(-8) M), but only if effector-target ratio equal to 20:1 was used (P less than 0.02), and by Mel (10(-12) M) for effector-target ratio equal to 40:1 (P less than 0.05). In none of the examined concentrations did NAc-5HT inhibit NK activity of human lymphocytes. On the basis of the data reported above, a direct suppressive effect of Mel (but not of NAc-5HT) on NK activity of human peripheral blood lymphocytes can be assumed.

Inhibitory effect of somatostatin on the basal and TSH-stimulated 3H-thymidine incorporation into rat thyroid lobes incubated in vitro.

The effects of somatostatin on the spontaneous and TSH--stimulated incorporation of tritiated thymidine into the rat thyroid lobes incubated in vitro were investigated. The rate of 3H-thymidine incorporation was used as an index of thyroid follicular cells (TFC) proliferation. It was shown that: 1) somatostatin, at a concentration of 10(-7)M, decreased 3H-thymidine incorporation into DNA of TFC, 2) the highest somatostatin concentration, as tested in this study (10(-6)M), produced a similar decreasing effect; the decrease, in this case, did not attain significance vs. controls, 3) somatostatin, when employed together with TSH, suppressed the stimulatory effect of the latter hormone on 3H-thymidine incorporation into DNA of thyroid lobes.