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Inhibin/activin subunit (α, βA, and βB) immunoreactive protein localization patterns and cell type specific inhibit α-subunit mRNA expression have been examined in early-to midgestational age human fetal testes. The scarcity of available third trimester human fetal tissue has, however, prevented a complete examination throughout the gestational period and the cell specific expression of follistatin...
Glucagon-like peptide-17–36NH2 (GLP-17–36NH2) is a potent stimulator of insulin secretion, as well as of somatostatin-14 (SS-14) release from the pancreatic and gastric D-cells. To investigate the possible effects of this peptide on release of intestinal somatostatin (SS-28 and SS-14), rat intestinal cultures were treated with 10−12–10−6M GLP-17–36NH2, as well as with the structurally related peptides,...
To determine whether insulin-like growth factor-I (IGF-I) plays a role in rabbit corpus luteum (CL) physiology the authors examined: IGF-I expression, the effect of IGF-I on progesterone (P) production in vitro, and the interaction of IGF-I with estradiol, the primary luteotropin in the rabbit. Northern blot analysis revealed that IGF-I mRNA is present in the rabbit CL throughout pseudopregnancy....
Interferon-tau (IFN-τ) is secreted by the bovine conceptus and may regulate synthesis of uterine endometrial cytokines to provide an environment that is conducive to embryo development and implantation. Interferon-τ stimulates secretion of an 8-kDa uterine protein (P8) in the cow. P8 was purified, digested to yield internal peptides, and partially sequenced to determine identity. Two internal peptides...
A 17 kDa fragment of human growth hormone (22 kDa hGH), identified as hGH44–191, has lower binding affinity for growth hormone receptors (GHRs), but has been reported to be more potent in producing glucose intolerance in yellow obese mice. Our aim was to investigate this anomaly by comparing acute development of hyperinsulinemia and insulin resistance (“diabetogenic activity”) during hGH44–191 or...
Neuropeptides are central to the regulation of mammalian gender-dependent development and reproduction. Preoptic regulatory factor-2 is a neuropeptide gene that is known to be expressed in rat brain and tesis (1). In the brain, expression is gender-dependent and age-dependent (2, 3). Tissue-specific transcripts are found in the preoptic area (POA) of the hypothalamus and in the testis (1). In order...
The heat-stable protein kinase inhibitor (PKI) protein is a specific and potent competitive inhibitor of the catalytic subunit of cAMP-dependent protein kinase (PKA). Previously, it has been shown that vitamin D status affects chick kidney PKI activity: a 5- to 10-fold increase in PKI activity was observed in kidneys of chronically vitamin D-deficient chicks and treatment with 1,25-dihydroxyvitamin...
The cytoplasmic Ca2+ concentration ([Ca2+]i) was measured with dual wavelength fluorometry in glucagon-producing mouse pancreatic α-cells loaded with the indicator fura-2. Spontaneous rhythmic activity in terms of slow oscillations from a basal level was observed at 3 mM glucose. Like in the insulin-secreting β-cells the generation of [Ca2+]i oscillations in the α-cells was affected by the activity...
The effects of dihydrotestosterone (DHT) (1 mg/kg) on biochemical parameters related to lacrimal secretion, basal tear flow rate, and pilocarpine-stimulated lacrimal gland fluid secretion, in mature ovariectomized rabbits were studied. The effects of the synthetic estrogen, diethylstilbestrol (DES) (100 μg/kg), on lacrimal gland biochemical parameters in normal mature female rabbits was also studied...
The presence of heat-shock protein 72 (HSP-72) was investigated by immunohistochemistry (IHC) in a series of 28 surgically removed pituitary adenomas including six somatotroph, two mammosomatotroph, five lactotroph, six corticotroph, four null cell adenomas, and three oncocytomas. Overall, 25 tumors (90%) were positive for HSP-72. One somatotroph, one lactotroph, and one null cell adenomas each contained...
Hormone-responsive peptides play a vital role in development and regulation of testicular function. The preoptic regulatory factors, porf-1 and porf-2, were originally discovered in the rat brain, but are also expressed in the rat and human testis. In the brain expression is age-related, hormone-responsive, region-specific, and gender-related, suggesting that porf-1 and porf-2 are involved in gender-specific...
The role of vasoactive intestinal peptide (VIP) in the regulation of dopamine (DA) concentration in mediobasal hypothalamus (MBH), posterior and anterior pituitary of ovariectomized (OVX) estrogenized rats was studied using passive immunization against VIP with a specific antiserum (a-VIP). Chronic estradiol administration decreased DA concentration in MBH, and in posterior and anterior pituitary,...
Gonadotropin-releasing hormone (GnRH) has been shown to play a role in the regulation of human chorionic gonadotropin (hCG) secretion by the human placenta. Molecular studies have demonstrated that human placental trophoblast cells synthesize a progonadotropin-releasing hormone (pro-GnRH) identical to its human hypothalamic counterpart. However, far less is known about nonhuman primates. To determine...
Plasma levels for insulin-like growth factor-I (IGF-I) steadily increase in female rats between 20 and 40 d of life, and this increase is intimately related to the wellknown growth spurt occurring at this age. Since specific actions of IGF-I related to sexual function have been described at the ovarian and hypothalamic levels, an endocrine role of rising circulating IGF-I levels during sexual maturation...
In the present investigation, the authors aimed to evaluate the role of cytokines in intestinal postnatal maturation induced by dietary polyamines. Neonatal rats were administered either saline or spermine (8 μmol) orally. Spermine increased interleukin-1β (IL-1β), IL-6, and TNF-α plasma concentration. The maximum concentrations of IL-1β, IL-6, and TNF-α were, respectively, observed at 4, 4, and 8...
Estrogen or progesterone replacement in ovariectomized rats is an often-used experimental system for determination of the specific effects of these hormones. In this study, two different delivery systems and two different dosage levels of estrogen, progesterone or a combination of the two have been used. Estrogen and progesterone in the circulation have been measured in response to each treatment...
Continuous withdrawal of hypophyseal portal blood from unrestrained sheep has permitted detailed assessments of the pulsatile secretion of gonadotrophin-releasing hormone (GnRH). To determine if this blood can also be used to characterize the secretory dynamics of pituitary hormones, patterns of luteinizing hormone (LH) in the hypophyseal portal blood of ovariectomized ewes was compared with previous...
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