Release of alpha-melanocyte-stimulating hormone from dispersed cells of the intermediate lobe of the rat pituitary gland: involvement of catecholamines and adenosine 3',5'-monophosphate.

Treatment of the neurointermediate lobe of the rat pituitary gland with mechanical agitation in the presence of trypsin and DNAse results in a preparation of cells which secrete alpha MSH and synthesize cAMP. The receptors for catecholamines present in the intact intermediate lobe remain functional on the dispersed cells. Thus, stimulation of a beta-adrenoceptor with (l)isoproterenol enhances the secretion of alpha MSH. This receptor is stereospecific and responds to low concentrations of isoproterenol (EC50 = 0.4 nM). Activation of a beta-adrenoceptor also increases the accumulation of cAMP. Furthermore, dopamine inhibits the basal release of alpha MSH but has no effect on basal levels of cAMP. In addition, dopamine inhibits the isoproterenol-enhanced release of alpha MSH as well as the isoproterenol-induced accumulation of cAMP.

Chronic estrogen treatment promotes a functional uncoupling of the D2 dopamine receptor in rat anterior pituitary gland.

The effect of chronic estrogen treatment on the anterior pituitary D2 dopamine receptor was studied by treating rats with diethylstilbestrol (DES) over a 6-week period. DES treatment resulted in an increase in anterior pituitary weight and PRL content and serum PRL levels compared to those in sham-treated controls. The status of the anterior pituitary D2 dopamine receptor was evaluated using both radioligand binding and adenylate cyclase assays. [125I]N-(p-aminophenethyl)spiroperidol [( 125I]NAPS), a derivative of the D2-selective antagonist spiperone, was used to quantitate D2 receptors. Saturation analysis of [125I]NAPS binding indicated that DES treatment had no effect on the affinity or maximum binding capacity of the radioligand for the D2 receptor. Competition analysis with unlabeled D2 antagonists for [125I]NAPS binding also indicated that DES treatment did not affect antagonist interactions with the receptor. In contrast, the interactions of agonists with the D2 receptors from DES-treated rats were modified, as assessed through [125I]NAPS competition analysis. Using control tissue, agonist competition curves revealed both high and low affinity agonist binding states of the receptor. In the presence of guanine nucleotides, the high affinity agonist binding state is abolished, reflecting coupling of the receptor with a guanine nucleotide regulatory (G) protein. In DES-treated tissue, agonist competition curves indicated the presence of only low affinity agonist binding, with minimal effects of guanine nucleotides, suggesting uncoupling of receptor-G-protein interactions. The functionality of the D2 receptor was further assessed by examining dopaminergic inhibition of vasoactive intestinal peptide-stimulated adenylate cyclase activity. Although DES treatment resulted in a reduction of vasoactive intestinal peptide-stimulated enzyme activity itself, the ability of dopaminergic agonists to inhibit this activity was reduced by about 50%. These results suggest that estrogen is capable of attenuating the functional coupling of the D2 receptor with its biochemical effector system in the anterior pituitary gland.

Biochemical identification of the beta-adrenoceptor and evidence for the involvement of an adenosine 3',5'-monophosphate system in the beta-adrenergically induced release of alph-melanocyte-stimulating hormone in the intermediate lobe of the rat pituitary gland.

The beta-adrenoceptor in the intermediate lobe (IL) of the hypophysis of the rat is characterized on the basis of the following: 1) the ability of beta-adrenergic agonists to increase adenylate cyclase activity in homogenates of the IL, and 2) the ability of drugs active upon the beta-adrenoceptor to compete with [125I]hydroxybenzylpindolol, a radiolabeled beta-adrenergic antagonist, for high affinity (Kd = 232 pM) binding sites. The values of the affinity of the beta-adrenoceptor for drugs obtained in either assay system are in good agreement. The relative potency among agonists, L-isoproterenol greater than L-epinephrine greater than L-norepinephrine, suggests that the receptor is of the beta-2 subcategory. cAMP, derivatives of cAMP, and a phosphodiesterase inhibitor, theophylline, mimic the ability of l-isoproterenol to enhance the release of alpha MSH from dispersed cells of the rat IL. The present results are in accord with the possibility that occupancy by agonists of the beta-adrenoceptor of the IL enhances adenylate cyclase activity, resulting in an accumulation of cAMP which initiates the intracellular events that are ultimately expressed as an enhanced release of alpha MSH. Pharmacological data suggest that stimulation of a dopamine receptor in the IL diminishes the response of the beta-adrenoceptor to agonists.

The dopamine receptor in the intermediate lobe of the rat pituitary gland: pharmacological characterization.

The dopamine receptor in the intermediate lobe (IL) of the hypophysis of the rat is characterized on the basis of the ability of dopamine and other dopaminergic agonists to decrease the consequences of activation of the beta-adrenoceptor. Stimulation of the dopamine receptor diminishes the L-isoproterenol-induced accumulation of cAMP and the catecholamine-stimulated enhancement of adenylate cyclase activity. The dopamine receptor in the IL can be assigned to the category of dopamine receptor designated D-2 on the basis of the following criteria: 1) occupancy of the dopamine receptor does not result in enhancement of adenylate cyclase activity or an accumulation of cAMP, 2) the dopaminergic ergots and apomorphine mimic the inhibitory effect of dopamine upon cAMP formation or alpha MSH release, and 3) metoclopramide and sulpiride, substituted benzamides, block the inhibitory effect of dopamine. The sympathetic neurotransmitter, norepinephrine, interacts with the dopamine receptor and the beta-adrenoceptor in the IL.

Endocrine profile of an ovarian androblastoma.

The endocrine profile of a 16-year-old girl with an androblastoma of the left ovary is presented. Calculated ratios of steroid hormones between the intraoperative peripheral vein blood, the left ovarian vein blood, and the left ovarian tumor fluid were progesterone, 1:10.2:39.5; 17-hydroxyprogesterone, 1:18.7:64.7; dehydroepiandrosterone (DHEA), 1:10.4:35.6; androstenedione (A), 1:24.4:92.3; testosterone (T), 1:18.6:69.2; and estradiol (E2), 1:11.0:26.3. The peripheral levels of hormones before left salpingo-oophorectomy were T, 7.5 ng/ml; DHEA, 19.9 ng/ml; A, 12.3 ng/ml; and cortisol, 11.4 micrograms/dl. Corresponding levels at 14 days after surgery were (0.75 ng/ml; 5.84 ng/ml; 1.94 ng/ml; and 15.6 micrograms/dl, respectively. Preoperatively, an elevated basal level of luteinizing hormone (LH) and a normal basal level of follice-stimulating hormone (FSH) (high LH:FSH ratio) were found. These data suggest that 1) androgens from the androblastoma are responsible for virilization despite aromatizing enzyme activities within normal limits, and 2) both the delta 5 and delta 4 pathways are involved in the biosynthesis of androgens, with that of delta 5 being predominant.

In vivo and in vitro studies on the production of placental proteins (human chorionic gonadotropin, human placental lactogen, and pregnancy-specific beta 1-glycoprotein) in an adrenal choriocarcinoma.

The ectopic production of placental proteins (human chorionic gonadotropin [hCG], human placental lactogen, and pregnancy-specific beta 1-glycoprotein) by an adrenal choriocarcinoma was investigated experimentally in vivo and in vitro. By an immunohistochemical method, the choriocarcinoma tissues obtained from the right adrenalectomy were found to react with hCG, human placental lactogen, and pregnancy-specific beta 1-glycoprotein antibodies. The concentrations of hCG-beta, human placental lactogen, and pregnancy-specific beta 1-glycoprotein in the tumor fluid were 1480, 100, and 47 ng/mL, respectively. On incubation of the tumor slices in vitro, the concentration of hCG-beta in the incubation medium increased markedly with time. Serial sections of the removed uterus and right ovary did not reveal any primary trophoblastic lesions. The present tumor responded well to double chemotherapy with actinomycin D and methotrexate, resulting in a decrease of the level of serum hCG-beta to less than 10 ng/mL after four courses of the chemotherapy.

The effects of A23187 and phorbol ester on the phosphorylation of proteins in rat anterior pituitary cells.

The effects of A23187 and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on the phosphorylation of proteins in normal rat anterior pituitary cells were compared. A23187 rapidly activated the phosphorylation of at least 5 proteins (45, 47, 53, 54 and 58 kDa), which reached the maximal level in 2-10 min, and decreased gradually thereafter. In contrast, TPA activated the phosphorylation of at least 6 proteins (45, 62, 64, 72, 76 and 82 kDa), which were mostly distinguished from those activated by A23187. TPA-induced response was elicited more slowly, reached a plateau after about 10 min, and was sustained thereafter. These results suggest that the protein phosphorylation stimulated by A23187 and TPA is conducted by different mechanisms.

Lisuride hydrogen maleate: an ergoline with beta-adrenergic antagonist activity.

Lisuride hydrogen maleate is identified as a potent beta-adrenergic antagonist using a hormone-sensitive adenylate cyclase system and [3H]dihydroalprenolol binding in cell free homogenates of rabbit cerebellum. Lisuride and two other ergolines, lergotrile and bromocriptine, and the phenothiazine, fluphenazine, all interact with spiroperidol binding sites (dopamine receptors) in the anterior pituitary; however, among these compounds lisuride is unique in its ability to antagonize the beta-adrenoceptor.

[Immunochemotherapy of recurrent and advanced uterine and ovarian cancer using cisplatin].

A combination immunochemotherapy regimen containing cisplatin (20 mg, days 1-5), peplomycin (20 mg, days 2, 9, 16), +/- vinblastine (5 mg, days 1, 2), and picibanil (3-5 KE/week) was performed in twelve patients with advanced or recurrent uterine and ovarian cancers under intravenous hyperalimentation (IVH), except one patient receiving peplomycin by a continuous infusion method using IVH bag (10 mg/day for 5 days). This regimen was repeated every three weeks. Five (71.4%) of seven evaluable patients showed partial response. No patients yielded the complete disappearance of disease. No severe and lethal pulmonary or renal dysfunction occurred and all was well tolerated. In a regimen without vinblastine, myelosuppression, especially thrombocytopenia, occurred later compared to the regimen including vinblastine.

Calmodulin and Ca2+- and calmodulin-dependent protein kinase in rat anterior pituitary gland.

Calmodulin and Ca2+- and calmodulin-dependent protein kinase were identified in the rat anterior pituitary gland. The concentration of calmodulin was 1.18 +/- 0.11 microgram/mg protein (n = 7) in the cytosol fraction. The calmodulin of the anterior pituitary gland co-migrated with brain calmodulin on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The Ka value of the partially purified enzyme for Ca2+ was 3.3 microM in the presence of 0.30 microM calmodulin. Trifluoperazine and chlorpromazine, calmodulin-interacting agents, inhibited enzyme activity, with Ki values of 1.3 and 2.6 X 10(-5) M, respectively. The enzyme was resolved into two peaks of activity, with sedimentation coefficients of 5.5 S and 16.5 S, by sucrose density gradient centrifugation. At least nine proteins were phosphorylated by the enzyme in a Ca2+- and calmodulin-dependent manner. In light of these results, the possibility that calmodulin and the calmodulin-activatable protein kinase system are involved in the mediation of the Ca2+ effect on hormone release from the anterior pituitary gland must be given consideration.

Primary malignant melanoma of the vulva associated with pregnancy: clinical, light and electron microscopic observations.

A case of primary malignant melanoma of the vulva associated with pregnancy in a 31-year-old patient is reported. The primary tumor was first found at week 14 of pregnancy and biopsied on delivery at week 41 of pregnancy. Microscopically, the depth of invasion was Level V. Radical vulvectomy and bilateral inguino-femoral lymphadenectomy were performed and the right inguinal lymph node was positive for metastatic tumor. Chemoimmunotherapy with DTIC, ACNU, VCR and OK432 was undertaken as treatment for this malignant melanoma. Moreover, a comparison of scanning and transmission electron microscopic studies of the original tumor was carried out. This patient is now living 23 months after diagnosis without clinical evidence of recurrence.

[The effects of cholera toxin in the release of beta-endorphin from the dispersed cells of the rat neurointermediate lobe].

The intermediate lobe cells of pituitary gland synthesize and secrete bioactive peptides derived from proopiomelanocortin. In the present study, we investigated the effects of cholera toxin on the release of beta-endorphin (beta-Ep) from dispersed-intermediate lobe cells of rats. Cholera toxin added into culture medium, enhanced the intracellular accumulation of adenosine 3', 5'-monophosphate (cAMP) and the release of beta-endorphin like immunoreactive substance (beta-END-LIS). A positive dose-response relationship existed between the concentration of cholera toxin and the release of beta-END-LIS or the accumulation of cAMP. Maximal response was obtained with approximately 3 X 10(-10) M (in beta-END-LIS release) and 1 X 10(-9) M (in cAMP accumulation) concentration of cholera toxin. Incubation with cholera toxin (3 X 10(-8) M) resulted in a significant rise of cAMP accumulation after 20-30 min, and a 2-2.5 fold increase of beta-END-LIS release occurred after 60 min in comparison with nontreated cells. cAMP analog and phosphodiesterase inhibitor also increased the beta-END-LIS release). These results suggested the close relationship between cAMP accumulation and its biological effect (i.e. beta-END-LIS release).

Endocrine studies on ovarian androblastomas (Sertoli-Leydig tumors).

Endocrine studies were made on 4 women with ovarian Sertoli-Leydig cell tumors of varying degrees of differentiation. Clinically, all 4 patients showed evidence of increased androgen production, manifested by either hirsutism or virilization. The calculated ratios of steroid hormones between the affected ovarian venous values and peripheral values for testosterone (T), androstenedione (A), and dehydroepiandrosterone (DHEA) in 3 patients, were 1.4-18.6, 4.2-24.4, and 3.7-10.0, respectively. The peripheral levels of the hormones before salpingo-oophorectomy in all the patients were T: 0.97-45.0 ng/ml; A: 2.92-114.0 ng/ml; and DHEA: 13.0-20.9 ng/ml. In the 3 juvenile patients, elevated basal levels of LH and normal or subnormal levels of FSH (high LH:FSH ratio) were found. In a 12-year-old patient with 1,900 g tumor composed predominantly of Sertoli cells with lipid storage, the peripheral serum levels of T and estradiol (E2) were 114 ng/ml and 1890 pg/ml, respectively. The present data suggest that: 1) androblastomas have a biosynthetic capacity for androgen, estrogen, or both in which both the delta 5 and delta 4 pathways are involved, and 2) little correlation exists between the endocrine function and cellular composition of the tumors or their degree of differentiation.

Demonstration of C-peptide immunoreactivity in various body fluids and clinical evaluation of the determination of urinary C-peptide immunoreactivity.

C-peptide immunoreactivity (CPR) was demonstrated not only in plasma, but in urine, ascites, cerebrospinal fluid and pleural effusion. The concentration of CPR in urine was very high compared with that in the other body fluids and was easy to assay. CPR in urine after glucose administration or tolbutamide injection increased parallel to the change of CPR in plasma and also to that of IRI in normals or diabetics without renal disturbances. The result suggest that the determination of CPR in urine before and after stimulation of insulin secretion could serve as a simple indicator of insulin secretory function of pancreas.

Massive edema of the ovary associated with hydrothorax and ascites.

A 29-year-old woman with massive edema of the ovary which was grossly mistaken for neoplasia because it was associated with large volumes of both pleural effusion and ascites is described. The ovarian mass measured 10 X 10 X 8 cm and weighed 850 g. Total hysterectomy and bilateral salpingo-oophorectomy were performed. Microscopically, the ovary consisted of diffusely edematous stroma enveloping nests of hyperplastic theca cells or showing a loose myxomatous contexture. However, no endocrine activity of the ovary was demonstrated on the basis of laboratory endocrine values obtained by radioimmunoassay techniques.