Electronic Library of Scientific Literature


Volume 29 / No. 4 / 1995

Distribution of Somatostatin Receptor Type 1 in the Rat. An Immunohistochemical Study


¹The Fourth Department of Internal Medicine, ²Laboratory Medicine, ³Department of Internal Medicine, Konanshowa Hospital, Konan, Aichi, Japan and
*First Department of Physiology, Aichi Medical University, Nagakute, Aichi, Aichi 480-11 Japan

Somatostatin receptor type 1 (SSTR-1) was identified immunohistochemically in the rat tissues using anti-peptide antiserum. Anti-somatostatin receptor antiserum was raised in New Zealand white rabbits immunized with a conjugate of synthetic SSTR-1 peptide (41-52) with bovine serum albumin. Immunohistochemical analysis was performed by the ABC method. SSTR-1 immunoreactivity was visualized in the central nervous system, anterior pituitary, mucosa of stomach and duodenum, Auerbach's nervous branch and Mysner's nervous branch of gastrointestinal tract and pancreas. Significant staining was detected in neural perikarya, axon and dendrite. When using antiserum preincubated with synthetic SSTR-1 peptide (41-52) or rat anterior pituitary homogenated which contains SSTR-1, no significantly stained anterior pituitary cells or neurons in the hypothalamus were detected.
These findings suggest that SSTR-1 is widely distributed and that this method is valuable in studying the distribution of somatostatin receptor in rats.

Key words: Somatostatin Receptor Type 1 - Rat - Immunohistochemistry
pp. 189-193

The Effect of Epitestosterone on Spermatogenesis in Rats


Institute of Endocrinology, CZ-11694 Praha, Czech Republic
¹Institute of Reproductive Medicine of the University, D-4400 Munster, F.R.G.

The effect of 3-week treatment with increasing doses of endogenous steroid with antiandrogenic properties, epitestosterone (ET), on the spermatogenesis was studied in adult male rats by flow cytometry and correlated with the effect on gonadotropin gene expression and secretion, on testosterone and dihydrotestosterone plasma levels and on the weight of testes and prostates. Epitestosterone was administered to the rats by means of silastic capsules of different lengths filled with the steroid. A decrease of the number of total spermatides in the epitestosterone treated animals was observed. In the group with the lowest dose of ET the number of elongated spermatides was significantly reduced. The number of germ cell types and their relative proportions were correlated with the endocrine parameters reported previously. Significant negative correlation between the pituitary content of LH and total number of germ cells per 1 g of testicular tissue and of the number of spermatides/g and between testosterone level in serum and the number of diploid cells in the animals treated with higher doses of ET was found. In the group with highest ET dose a negative correlation of diploid cells and serum dihydrotestosterone was observed, too. The naturally occurring antiandrogen epitestosterone can be considered as one of the endogenous factors influencing spermatogenesis.

Key words: Epitestosterone - Spermatogenesis - Spermatides - LH
pp. 195-199

Effect Operative Weight Reduction on Hypothalamo-Pituitary, -Adrenal and -Ovarian Axes Function in Obese Women with Menstrual Disturbances


1st Department of Pathophysiology and Clinical Biochemistry, Silesian Academy of Medicine, 41-800 Zabrze, Poland

The aim of the study was to evaluate insulin (Ins), pituitary hormones (GH, PRL, LH, FSH), sex hormone-binding globulin (SHBG) and insulin-like growth factor-I (IGF-I) under basal conditions as well as the changes in GH, PRL and F levels after insulin-induced hypoglycemia in 21 obese women before and one year after jejunoileostomy as well as in 20 healthy female volunteers with normal body weight (aged 27 to 36 years). Before surgery all obese women had irregular menstrual cycles. In 14/21 non-operated morbidly obese women and after operative weight reduction (jejunoileostomy), the GH, PRL and F response to insulin-induced hypoglycemia was lower than that in non-obese healthy controls. No difference, however, was observed in GH, PRL and F secretion in non-operated obese women as compared with obese women after jejunoileostomy. Hypothalamic disturbances in the release of GH, PRL and F corresponded to higher levels of sex steroid hormones, IGF-I, and also to lower values of LH/FSH index and SHBG capacity in serum. After jejunoileostomy the pituitary-ovarian axis function as well as SHBG and IGF-I concentrations were normalized only in patients with a noted body mass reduction and with normal preoperative GH, PRL and F secretion dynamics. In these women the menstruation became regular.

Key words: Hypothalamo-Pituitary-Axis - Adrenal Cortex - Ovary - Morbid Obesity - Jejunoileostomy - Insulin Hypoglycemia
pp. 201-213

Central Adrenergic System Does Not Contribute to Morphine Stimulated Pineal Secretion of Melatonin


I Department of Pathophysiology and Medical Analytics, Silesian University School of Medicine, 41-800 Zabrze, Poland

The effect of long-term morphine treatment of rats subjected to central chemical sympathectomy (CCS) was studied. The experiment was performed on 7-week-old male Wistar rats. CCS was performed with 6-hydroxydopamine injected into the lateral ventricle of the brain. The serum concentration of melatonin was assayed by specific RIA.
The study showed that morphine alone significantly increased melatonin concentrations in serum. CCS alone significantly decreased melatonin concentrations in serum at the time of highest secretory activity of the pineal gland. Long-term morphine treatment of rats subjected to CCS significantly increased the serum concentration of melatonin. Therefore, it may be concluded that the central adrenergic system does not take part in the morphine-stimulated secretion of melatonin.

Key words: Melatonin - Morphine - Central Sympathectomy - 6-OHDA - Pineal Gland
pp. 215-219

Immunohistochemical Investigation on G and D Cell Number in Antral Mucosa in Patients with Helicobacter-Pylori Related Gastritis


Department of General and Clinical Pathology, Medical Institute, Stara Zagora, Bulgaria

G and D cells in antral mucosa of 12 patients with clinical and morphological diagnosis of Helicobacter pylori related chronic gastritis were investigated. In all cases D cell number was significantly decreased (P < 0.05). G cell number did not show any significant difference as compared with control patients except for the cases with moderate gastric mucosal atrophy, where even G cells decreased in number. The results showed that elevated gastrin secretion as observed in H. pylori infected patients might result from reduced inhibition of G cells' secretion by D cells' producing somatostatin.

Key words: G cell - D cell - Gastrin - Somatostatin - Chronic Gastritis - Immunohistochemistry
pp. 220-224

Luliberin Inhibits the Release of Oxytocin from Hypothalamo-Neurohypophysial System in Dehydrated But Not in Euhydrated or Haemorrhaged Rats


Department of Pathophysiology, University School of Medicine, 60 Narutowicza Street, 90-136 Lodz, Poland

Rats euhydrated, dehydrated for two days or haemorrhaged were given intracerebroventricularly (i.c.v.) luteinizing hormone releasing hormone (LH-RH) in a daily dose of 100 ng dissolved in 10 microl of 0.9 % sodium chloride.
In euhydrated rats, a single i.c.v. dose of LH-RH as well as the daily i.c.v. treatment with LH-RH for two days did not affect significantly either the plasma oxytocin concentrations or the hypothalamo-neurohypophysial oxytocin content. In animals dehydrated for two days and treated with LH-RH the increase in plasma oxytocin was almost suppressed and the depletion of neurohypophysial hormone content was significantly less marked.
Luliberin treatment had no effect on the hypothalamo-neurohypophysial content of oxytocin as well as on plasma oxytocin concentration in haemorrhaged rats.
We suggest that LH-RH may have a regulatory role in the hypothalamo-neurohypophysial oxytocinergic system, especially under hyperosmotic dehydration.

Key words: Oxytocin - LH-RH - Dehydration - Bleeding
pp. 225-231

Influence of Arginine-8-Vasotocin and Indomethacin on in vitro Progesterone Secretion by Porcine Granulosa Cells


Institute of Cell Biology and Morphology and ¹Institute of Physiology, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria

The effect of the nonapeptide hormone arginine-8-vasotocin (AVT) and indomethacin on progesterone (P) production by cultured granulosa cells (GCs) from porcine preovulatory follicles was investigated. AVT dose-dependently stimulated the release of P by GCs. Basal and AVT-stimulated P secretion was inhibited when cultures were pretreated with the cyclooxigenase inhibitor indomethacin. These results suggest that AVT is involved in the local control of porcine follicle functions and that the effects of AVT on the P release are dependent on the endogenous production of prostaglandins (PGs) in the GCs.

Key words: Granulosa Cells - Progesterone - Arginine-8- Vasotocin - Indomethacin
pp. 232-236

Ovarian Sources of Preovulatory Progesterone Peak in the Rat


Laboratory of Animal Endocrinology and Tissue Culture, Department of Animal Physiology, Institute of Zoology, Jagiellonian University, Ingardena 6, 30 060 Krakow, Poland

The content of progesterone and oestradiol was estimated in three generations of corpora lutea (CL) isolated from rat ovaries at 11.00 and 18.00 h at consecutive stages of 4-day oestrous cycle. The highest amount of progesterone was found in the youngest CL on the day of metoestrus and on the morning of dioestrus. The second, much lower rise was observed in this generation on the evening of pro-oestrus. The progesterone concentration was relatively high in the older CL at oestrus but decreased thereafter. The oldest CL contained very little of progesterone. All generations of CL contained very low amounts of oestradiol. These results suggest that not only the preovulatory follicles but also the youngest CL can contribute to progesterone peak before the ovulation in rats. As judged from CL progesterone content, morphological analysis, CL weight and size, full luteolysis of CL takes place when they are about 6 days old.

Key words: Progesterone - Corpora Lutea - in vitro - Time Changes - Oestrous Cycle - Rats
pp. 237-243