Exon scrambling of MLL transcripts occur commonly and mimic partial genomic duplication of the gene

The aim of this study was to test the hypothesis that prolactin may up- and down-regulate prolactin receptor gene expression in the anterior pituitary gland and hypothalamus respectively. Experiments were carried out in bantams (Gallus domesticus). Comparisons were made of concentrations of PRLR mRNA in the anterior pituitary gland and basal and preoptic hypothalamus in adult males and females held on long days (low vs high plasma prolactin); in 3-week-old juvenile male and females on short days (high vs low plasma prolactin); in 8-week-old juvenile male and females on short days (both low plasma prolactin); in adult laying, incubating, and out-of-lay (high, very high, and low plasma prolactin, respectively); in adult cockerels exposed to long or short days (high vs low prolactin); and in adult hens exposed to long or short days (high vs low prolactin). There was a sex difference in anterior pituitary and basal hypothalamic PRLR mRNA, with lower values in both tissues in females than in males. Compared with laying and out-of-lay hens, anterior pituitary and basal hypothalamic PRLR mRNA concentrations in incubating hens were increased and decreased, respectively. In adult birds of either sex held on long or short days, there was no difference in pituitary PRLR mRNA, while basal hypothalamic PRLR mRNA was lower on short days. PRLR mRNA in the preoptic hypothalamus was not affected by sex, reproductive state, or photoperiod. It is concluded that there is no consistent relationship between plasma prolactin, in the physiological range, and the concentration of PRLR mRNA in the anterior pituitary gland, basal hypothalamus, and preoptic hypothalamus.     

The effect of posterior lobe extract, adrenalin, and pilocarpine on the response of the thyroid gland to the thyreoactivator hormone of the anterior lobe of the hypophysis

The studies reported here were directed toward ascertaining in a variety of organisms whether or not any of the three lobes of the pituitary gland affected thyroid activity. We documented a thyroid stimulating action of the anterior lobe of the pituitary gland extract that was not shared in by either the intermediate or posterior lobes. Pilocarpine first depressed the stimulating action of the pituitary extract but, after the fifth injection, it accentuated the response of the thyroid gland to the pituitary extract.     

Intercellular communication within the rat anterior pituitary gland: VI. Development of gap junctions between folliculo-stellate cells under the influence of ovariectomy and sex steroids in the female rat

BACKGROUND: Farquhar (1957) initially described the folliculo-stellate cells in the rat anterior pituitary gland and found them to be located in groups around follicles throughout the anterior lobe. Soji and his co-workers have published a series of reports concerning cell-to-cell communication in the male rat hypophysis involving folliculo-stellate cells as mediated through a gap junctional network and recorded a reduction in junctional number following castration that was reversed by the administration of testosterone (Soji and Herbert, 1990, Anat. Rec., 226:342-346; Soji et al., 1990, Anat. Rec., 226:337-341). METHODS: Animals were ovariectomized at 10 days of age and separated into three groups: (1) intact control, (2) ovariectomized controls, (3) ovariectomized and given either estradiol, testosterone, or progesterone. On days 10, 20, 30, 40, and 45, the pituitary gland from animals in each group was removed and processed for ultrastructural examination. RESULTS: Gap junctions in the intact control female rats initially appeared between adjacent folliculo-stellate cells on day 20. Their numbers linearly increased until the animals reached the age of 45 days. In contrast, there was a suppression in the number of gap junctions present in the ovariectomized groups and a marked enhancement of the junctions in each of the three steroid-treated groups. CONCLUSIONS: These findings support the observations made in the male rat in which it was found that the development of gap junctions in the anterior pituitary gland of the rat is dependent in part on the presence of sex steroid hormones.     

NGF content and expression in the rat pituitary gland and regulation by thyroid hormone

The involvement of nerve growth factor (NGF) in neuroendocrine regulation is supported by several lines of evidence. In this paper, we investigated the NGF content and expression in the pituitary gland and other endocrine organs during dysendocrine states (thyroidectomized, adrenalectomized and gonadectomized male rats). We found an increase of NGF-IR in the pituitary gland and testis of hypothyroid rats whereas no differences were found in the adrenal gland and blood. Also, NGF mRNA expression had increased in the anterior pituitary of hypothyroid rats whereas it had not changed after adrenalectomy and gonadectomy. Moreover, other neurotrophins and neurotrophin high-affinity receptors were unchanged in the anterior pituitary of hypothyroid rats. These data indicate that pituitary NGF is selectively modulated by thyroid status of the animal, further supporting a close link between NGF and thyroid hormone.     

Calcitonin gene-related peptide- and substance P-like-immunoreactive innervation of the anterior pituitary in the rat

In our previous studies substantial amounts of substance P- and calcitonin gene-related peptide-like-immunoreactive nerve fibers have been identified in the anterior pituitary of the monkey and the dog. They were found to be in close proximity to the gland cells, even making synaptic contacts with some types of the gland cells. The present study investigated in detail the calcitonin gene-related peptide- and substance P-like immunoreactivities of the anterior pituitary in the rat. Though the immunoreactive fibers were not as abundant as in the anterior pituitary of the monkey and the dog, they still appeared in notable amounts. The calcitonin gene-related peptide- and substance P-like-immunoreactive nerve fibers occurred mostly as thin, tortuous, and densely varicose fibers, weaving among the gland cells. They are widely distributed, more in the central part of the gland. Double-immunostaining proved nearly complete co-localization of these two peptides in the nerve fibers. It is hypothesized that the anterior pituitary can be regulated by direct neural factors as well as humoral factors.     

Effect of pituitary adenyl cyclase activating polypeptide on the cells of anterior pituitary cells

Pituitary adenylate cyclase activating polypeptide was first isolated from sheep hypothalamus by its potent activity in stimulating cyclic adenosine monophosphate production in anterior pituitary cells. The present review deals with the actions of this polypeptide on anterior pituitary cell types and with the putative role of the polypeptide as a hypophysiotropic factor regulating anterior pituitary cell activity. The evidence to date is strongly suggestive that pituitary adenylate cyclase activating polypeptide may act not as a "classic" hypophysiotropic factor stimulating or modifying anterior pituitary hormone release in vivo, since it does not appear in vitro to be a particularly potent stimulator of hormone release. The polypeptide rather may modulate the responses to factors such as gonadotrop hormone releasing hormone or have more general actions by regulating hormone synthesis or cell differentiation. Pituitary adenylate cyclase activating polypeptide also has indirect actions on anterior pituitary cell activity by stimulating the release of the paracrine factor interleukin-6. Its receptors appear to be present on most of the anterior pituitary cell types and unlike many other hypophysiotropic factors, pituitary adenylate cyclase activating polypeptide interacts with most, if not all, of the anterior pituitary cell types. Its exact effects and mechanisms of action in the anterior pituitary gland are still poorly understood.     

Pterional craniotomy via a transcavernous approach for the treatment of low-lying distal basilar artery aneurysms

OBJECT: The author describes a surgical procedure in which pterional craniotomy is performed via a transcavernous approach to treat low-lying distal basilar artery (BA) aneurysm. This intradural procedure is compared with the extradural procedure described by Dolene, et al. METHODS: The addition of a transcavernous exposure to the standard pterional intradural transsylvian approach allows a lower exposure of the distal BA behind the dorsum sellae. The technical steps involved in this procedure are as follows: 1) removal of the anterior clinoid process: 2) entry into the cavernous sinus medial to the third nerve; 3) packing of the venous channels of the cavernous sinus lying between the carotid artery and the pituitary gland to open this space; 4) removal of the posterior clinoid process and the portion of the dorsum sellae that is exposed from within the cavernous sinus; and 5) removal of the exposed dura mater to obtain additional exposure of the peri-mesencephalic cistern. Eight cases of aneurysms of the distal BA are presented to illustrate how this approach can help in their surgical treatment. CONCLUSIONS: Using the standard pterional approach, these distal BA aneurysms were found to be either too low relative to the posterior clinoid process for adequate exposure or there was insufficient room for temporary clipping of the BA proximal to the lesion. The addition of a transcavernous exposure eliminated these technical problems and aneurysm clipping could be accomplished in each case.     

Pathophysiological role of the cytokine network in the anterior pituitary gland

Recent evidence has demonstrated that cytokines and other growth factors act in the anterior pituitary gland. Using the traditional criteria employed to determine autocrine or paracrine functions our review shows that, in addition to their role as lymphocyte messengers, certain cytokines are autocrine or paracrine regulators of anterior pituitary function and growth. The cytokines known to regulate and/or be expressed in the anterior pituitary include the inflammatory cytokine family (IL-1 and its endogenous antagonist, IL-1ra; TNF-alpha, and IL-6), the Th1-cytokines (IL-2 and IFN-gamma), and other cytokines such as LIF, MIF, and TGF-beta. This review examines at the cellular, molecular, and physiological levels whether: (1) each cytokine alters some aspect of pituitary physiology; (2) receptors for the cytokine are expressed in the gland; and (3) the cytokine is produced in the anterior pituitary. Should physiological stimuli regulate pituitary cytokine production, this would constitute additional proof of their autocrine/paracrine role. In this context, we analyze in this review the current literature on the actions of cytokines known to regulate anterior pituitary hormone secretion, selecting the in vivo studies that support the direct action of the cytokine in the anterior pituitary. Further support for direct regulatory action is provided by in vitro studies, in explant cultures or pituitary cell lines. The cytokine receptors that have been demonstrated in the pituitary of several species are also discussed. The endogenous production of the homologous cytokines and the regulation of this expression are analyzed. The evidence indicating that cytokines also regulate the growth and proliferation of pituitary cells is reviewed. This action is particularly important since it suggests that intrinsically produced cytokines may play a role in the pathogenesis of pituitary adenomas. The complex cell to cell communication involved in the action of these factors is discussed.     

Reversible hyperintensity of the anterior pituitary gland on T1-weighted MR images in a patient receiving temporary parenteral nutrition

We report a patient with severe anorexia nervosa, treated with temporary total parenteral nutrition (TPN), in whom reversible hyperintensity of the anterior pituitary gland was seen on T1-weighted MR images. The anterior pituitary was isointense with white matter before TPN therapy and became markedly hyperintense after 3 months of treatment. The intensity normalized after TPN therapy was discontinued. The transient hyperintensity was also seen in the basal ganglia and dorsal brain stem. We believe the hyperintensity of the anterior pituitary may be attributed to the TPN therapy.     

Phenomenon of intrinsic rhythm of luteinizing hormone release from isolated anterior pituitary gland of female rat

The intrinsic nature of rthymic release of luteinizing hormone (LH) of isolated human and rat anterior pituitary gland reported independently by Macro Gambacciani and Xie in 1987 can be more directly demonstrated by a computer programme of Time Series-HSY Hidden Periodic Analytic Approach for continuous monitoring the LH output of the perfusate from a perfusion system with in vitro anterior pituitary of SD female rat. The results are as follows: (1) Under various reproductive conditions the average frequency (min/cycle) and amplitude (ng/ml) of the intrinsic rhythm of LH release were quite different: In proestrous group the frequency and amplitude were the highest, being intermediate in the ovariectomized group and lowest in the lactation group. (2) The intrinsic rhythm of LH release could be changed by either peptide or steroid hormones. In proestrous group with 30 min of gonadotropin-releasing hormone (GnRH), stimulation would reduce both frequency and amplitude. In case of lactation, the frequency was unchanged, but amplitude lowered, while in the ovariectomized rat pituitary, the 30 min GnRH stimulation decreased the frequency of release only. The intrinsic rhythm of the LH release could also be influenced by steriod hormones (Ru486 and Anordrin). With 120 min before removal of the anterior pituitary gland the rats receiving i.m. injection of Ru486 (2 mg/kg bw) or Anordrin (2 mg/kg), the results showed that Ru486 decreased frequency, while Anordrin decreased only the frequency to a less extent, both without amplitude affected. (3) Verapamil and EGTA added to the perfusion system did not abolish but only decreased the rhythmic phenomenon by using proestrous pitutary. This suggests that participation of Ca2+ may take place in the intrinsic release of LH. The above results indicated that the intrinsic rhythm of LH release of isolated anterior pituitary gland is different from various reproductive hormonal conditions and capable of being modified by exogenous hormones. The physiological function of the intrinsic rhythm of LH release of anterior pituitary gland remains to be elucidated.     

Identification of mammosomatotrophs in the turkey hen pituitary: increased abundance during hyperprolactinemia

We have previously reported that the hyperprolactinemia in incubating turkey hens is associated with recruitment of lactotrophs in the pituitary gland. In this study we have used double immunofluorescence and in situ hybridization histochemistry to 1) identify mammosomatotrophs in the anterior pituitary gland of egg-laying turkey hens and incubating hens, and 2) verify PRL gene expression within mammosomatotrophs by colocalizing PRL messenger RNA in GH-immunoreactive (ir) cells. The pituitaries of laying and incubating turkey hens were collected, and the midsagittal sections were dual labeled for either PRL and GH or PRL messenger RNA and GH. The plasma PRL concentrations were higher in incubating hens (231 +/- 10.6 ng/ml) than in laying hens (43 +/- 7.4 ng/ml; P < 0.01). In the midsagittal pituitary sections, mammosomatotrophs were predominantly found scattered in the caudal lobe of the anterior pituitary gland, in the ventral half of the cephalic lobe, and at the junction of cephalic and caudal lobes. In incubating hens, the proportion of mammosomatotrophs was 7.4 +/- 1.52% (mean +/- SEM) of the total number of GH-ir and/or PRL-ir cells counted, which was significantly higher (P < 0.05) than that found in laying hens (0.6 +/- 0.23%). Furthermore, PRL gene expression was observed in many GH-ir cells in the incubating hen pituitary gland. These data suggest that 1) mammosomatotrophs are present in the turkey pituitary gland, and 2) there is an increased abundance of mammosomatotrophs in the incubating turkey hen that may contribute to hyperprolactinemia.     

Consequences of prenatal morphine exposure on the hypothalamo-pituitary-adrenal axis in the newborn rat: effect of maternal adrenalectomy

The hypothalamo-pituitary-adrenal axis is already functional in rat fetuses in late gestation. We have reported previously that prenatal morphine exposure induced a severe atrophy of the adrenals and a decrease of corticosterone release in newborn rats at birth and during the early postnatal period. The first aim of the present study was to determine the effects of prenatal morphine exposure (1) on corticotrophin releasing factor (CRF) content of the hypothalamus, CRF immunofluorescence in the median eminence, CRF mRNA in the paraventricular nucleus (PVN) and pro-opiomelanocortin (POMC) mRNA in the anterior pituitary gland; (2) on CRF-induced ACTH release from the anterior pituitary gland in vitro; and (3) on ACTH-induced corticosterone release by the adrenals in vitro. Moreover, as morphine is a hepatotoxic factor, we determined the effects of prenatal morphine on liver weight and plasma corticosteroid binding globulin (CBG) binding capacity in newborn rats. Since acute administration of morphine stimulates corticosterone secretion in adult rats and since maternal corticosterone can cross the placental barrier, we also measured both adrenal weight and glucocorticoid activity in newborns from adrenalectomized mothers treated with morphine. The present results show that prenatal morphine given to intact mothers induced adrenal atrophy and hypoactivity in newborns but did not affect the responsiveness of the anterior pituitary gland to CRF or that of the adrenal gland to ACTH. Prenatal morphine reduced both CRF content in the newborn hypothalamus and CRF immunofluorescence in the median eminence without a significant effect on CRF mRNA expression in the PVN. Moreover, morphine induced a significant decrease of POMC mRNA in the anterior pituitary gland. However, morphine did not significantly affect the weight of the liver, or the plasma CBG binding capacity for corticosterone, in rat pups. In contrast, morphine treatment of the adrenalectomized mothers did not induce adrenal atrophy in newborns and did not impair adrenal activation during the early postnatal period. Maternal adrenalectomy also prevented the effects of prenatal morphine on hypothalamic content of CRF, CRF immunofluorescence in the median eminence, and POMC mRNA in the anterior pituitary gland. However, adrenal atrophy was observed at term in newborns of adrenalectomized mothers treated with both morphine and corticosterone or only corticosterone. In conclusion, morphine given to pregnant rats induced inhibition of the hypothalamo-pituitary-adrenal axis in pups at term. As maternal adrenalectomy prevented these effects, we speculate that an adrenal factor of maternal origin, probably corticosterone, mediated these drug effects on newborns.     

Denervation of the rat posterior pituitary gland: validation of a stereotaxic method

A stereotaxic surgical method was developed for interrupting the nerve fibres running through the rat pituitary stalk to the posterior pituitary gland without obliterating the hypothalamo-pituitary portal circulation. The pituitary stalk was compressed by the blunt tip of an L-shaped rotating knife. Successful operations produced mild diabetes insipidus, disappearance of arginine vasopressin from the neural lobe, accumulation of arginine vasopressin and neurosecretory material in the pituitary stalk and no infarction in the anterior lobe of the pituitary gland. In female rats, the oestrous cycle was only temporarily disturbed. Plasma prolactin and corticosterone levels were high during the first 24 h after the stalk compression but returned to normal baseline levels from the second day after the operation. One week after the operation plasma adrenocorticotropin and prolactin levels were in the control range while plasma alpha-melanocyte-stimulating hormone was elevated. Denervation of the posterior pituitary gland may help in studying the neural control of intermediate lobe function and the role of the neural lobe in various endocrine conditions, and may serve as a model for lesions of the pituitary stalk and formation of ectopic neurohypophysis in the human.     

Reversal of cyclosporine-inhibited low-density lipoprotein receptor activity in HepG2 cells by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

The effects of diethylstilbestrol (DES) and of long-acting somatostatin analog, octreotide (SMS) on the rat anterior pituitary microvasculature have been studied by means of computer-assisted image analysis. Additionally, the effects of DES and SMS on prolactin secretion and anterior pituitary cell proliferation have been studied, as well. The vascularization was visualized using Selye's method modified by Poely et al. (1964). The prolactin serum levels were estimated by radio-immunoassay. The proliferation indices were assessed using bromodeoxyuridine incorporation assay. As expected, it was found that DES sharply increased serum prolactin levels and enhanced cell proliferation in the anterior pituitary gland. DES also induced changes in parameters of vascularization. Simultaneous treatment of rats with SMS inhibited the DES-induced elevation of prolactin levels and pituitary cell proliferation. It also suppressed some but not all DES-induced changes in the anterior pituitary vascularization. These data suggest that the angio-inhibitory activity of SMS might be involved in its anti-tumor action on pituitary adenomas, but not as a sole or principal mechanism.     

Effects of photoperiod on hypothalamic and anterior pituitary tachykinins of male Siberian hamsters during development

In previous reports from our laboratory we showed that the hypothalamus and especially the anterior pituitary gland of the Siberian hamster contain very high concentrations of substance P- and neurokinin A-like immunoreactive substances, as compared with other common laboratory rodents. It was thought, therefore, that a study of the developmental changes of these two tachykinins in the hypothalamus and anterior pituitary of male Siberian hamsters would be of interest. In addition, as this species is very sensitive to changes in environmental light, these studies were carried out in animals kept under short or long daily photoperiods. The results of this investigation show that in male Siberian hamsters, photoperiod did not markedly influence the hypothalamic concentrations of substance P- and neurokinin A-like immunoreactive substances, which steadily increased from prepuberty up to 40-50 days of age. The influence of photoperiod, however, was much more marked on tachykinin levels in the anterior pituitary gland, because the developmental increase of tachykinins in this gland was significantly more evident in animals kept under short daily photoperiods than in animals under long daily exposure to light. These results are similar to those previously obtained in female Siberian hamsters, in spite of the fact that estradiol and testosterone seem to have opposite effects on anterior pituitary tachykinin concentrations. It seems, therefore, that, in addition to gonadal steroids, other factors may be important mediators of the tachykinin response to photoperiods in the anterior pituitary of the male Siberian hamster.     

High signal in the adenohypophysis on T1-weighted images presumably due to manganese deposits in patients on long-term parenteral nutrition

Hypermanganesaemia is reported in patients on long-term parenteral nutrition. Deposition of manganese, giving high signal on T1-weighted images, may involve the basal ganglia. MRI in nine patients (mean age 51 years, range 31-75 years) on long-term parenteral nutrition (mean duration 30 months, range 6-126 months), demonstrated high signal in the anterior pituitary gland on T1-weighted sagittal and coronal images. The gland appeared normal on T2-weighted images. Signal intensity in the basal ganglia on T1-weighted images was increased in all patients. Endocrine assessment showed no significant abnormality. Neurological examination showed a mild parkinsonian movement disorder in one patient. Hypermanganaesemia was present in all nine (1.3-2.8 micromol/l, mean 1.87 micromol/l). The high signal in the anterior pituitary gland was probably related to deposition of paramagnetic substances, especially manganese.     

Immunohistochemical distribution of oestrogen receptor and luteinizing hormone B subunit in the ovine pituitary gland during foetal development

The presence of oestrogen receptor in the developing hypothalamo-hypophyseal system is an essential prerequisite for the development of sex-steroid feedback on gonadotrophin secretion. We have used dual immunocytochemistry to examine the ontogeny and regional distribution of oestrogen receptor and LHbeta subunit in the ovine pituitary gland during foetal development. At day 65 gestation (term= 145 days) oestrogen receptor and LH/ immunopositive cells are found in a small region at the base of the anterior pituitary gland, and also in a band immediately adjacent to the neurointermediate lobe. By day 100 gestation there was a significant increase in the number of immunopositive LHbeta cells accounting for around 12% of the total cell population, and these were widely distributed throughout the anterior pituitary gland. There was also a significant increase in the proportion of gonadotrophs which contain oestrogen receptor compared with day 65. By day 130 gestation the percentage of LH containing cells had declined to around 7% of the total population, but the proportion which also contained oestrogen receptor remained the same. There were no differences in the numbers or distribution of cells containing LH or oestrogen receptors between male and female foetuses, at any age. These data describing a parallel change in the number of oestrogen receptors and LHbeta containing cells in the pituitary gland throughout gestation suggest that the development of pituitary sex-steroid feedback is not solely dependent on changes in the numbers of oestrogen receptor containing cells alone.     

Human fetal pituitary gland in holoprosencephaly and anencephaly

The normal prenatal development of the human pituitary gland and the gland-supporting sella turcica has recently been investigated. The sella turcica area constitutes a developmental boundary area in the cranial base. Posterior to the area the cranial base has developed close to the notochord, and anterior to the region the cranial base development is dependent chiefly on neural crest cell migrations. In the present study the sella turcica region was analyzed in two fetuses with holoprosencephaly (cyclopia and median cleft) and four fetuses with anencephaly combined with rachischisis in the neck region (GA 16-20 weeks). The sella turcica region was investigated radiologically and histologically. Adenohypohyseal gland tissue was localized by immunohistochemical hormonal marking. In both types of malformation an open craniopharyngeal canal was seen in the base of the sella turcica with adenohypophyseal glandular tissue located in the sella turcica, in the canal, and in the pharyngeal connective tissue at the external side of the cranial base. In conclusion, severe malformations of the pituitary gland occur in both holoprosencephaly, which is a polytopic field defect located anterior to the sella turcica, and in anencephaly associated with notochordal insufficiency posterior to the sella turcica. This might indicate that the sella turcica area, bounding different developmental fields, is involved in various craniofacial malformations. It is consequently recommended that examination of the pituitary gland should become a part of the routine autopsy of prenatal material when malformations in the face, brain, and cranial base occur.     

Differential Fos expression induced by IL-1beta and IL-6 in rat hypothalamus and pituitary gland

IL-1beta has been implicated in central nervous system effects, including activation of the hypothalamic-pituitary-adrenal axis. Less is known concerning the role of IL-6 in brain. To compare and contrast IL-1beta and IL-6 effects on brain, rats were administered intraperitoneal injections of IL-1beta, IL-6 or control vehicle (3-8 microg/rat), perfused 150-180 min post-injection, and brains and pituitaries were processed for Fos immunolabeling. IL-1beta induced Fos expression in corticotrophin-releasing factor (CRF) neurons of paraventricular nucleus (PVN) of the hypothalamus, and anterior pituitary gland. IL-6 also induced immunolabeled Fos in the anterior pituitary gland, however, it did not induce Fos expression in CRF neurons of PVN. Data suggest that IL-6 may directly activate the anterior pituitary gland, whereas IL-1beta may exert its effect on the pituitary directly and/or indirectly via activation of CRF neurons in the PVN.     

Nephrotic syndrome in a patient with HIV infection and juvenile onset diabetes: diagnostic, therapeutic, and prognostic value of the renal biopsy

The effects of the native somatostatin-14 (SST-14) and of its analog octreotide (OCT) on the activity of protein tyrosine kinases (PTK) in the normal rat anterior pituitary gland, diethylstilbestrol (DES)-induced rat pituitary tumor and murine colonic cancer Colon 38 were studied in vitro. PTK activity was estimated in tissue homogenates using gamma-[32P]ATP and poly (Glu80, Tyr20) as a substrate. It was found that both SST-14 and OCT suppressed the PTK activity in all examined tissues. The suppressive effect was more pronounced in DES-induced pituitary tumor than in normal anterior pituitary gland, and in the former, OCT was more effective than SST-14. In contrast, SST-14 stronger suppressed PTK activity in colonic cancer than OCT. We hypothesize that SST-14 acts on PTK activity in colonic cancer mainly via SSTR-1 subtype of somatostatin receptors.