ABSTRACTcDNA encoding pheromone-binding protein (PBP), the major soluble protein in olfactory sensilla of male moths, has been cloned from the tobacco hornworm, Manduca sexta. A study of the developmental time course of PBP reveals that it is first synthesized just prior to eclosion and that the percentage of antennal mRNA encoding PBP shifts from zero to about 20% at that time. PBP is also found in sensilla from female M. sexta antennae. No amino acid sequence homology is observed between PBP and the vertebrate odorant-binding protein.For terrestrial animals to detect airborne odorants via their olfactory receptor cells the volatile molecules must be first partitioned from a gaseous to an aqueous phase. In the vertebrate nasal epithelium dendrites of the olfactory receptor cells are submerged in a hydrophilic mucus that separates and protects them from the external environment. In insects, such as moths, an analogous barrier exists between the olfactory dendrites and the atmosphere. Most of the antennal sensilla of the moths are specialized to detect odorants. In several moth species, such as the tobacco hornworm, Manduca sexta, only the males possess the long trichoid sensilla that are specifically sensitive to pheromone released by females (1, 2). These sensilla are hollow cuticular structures containing the receptor cell sensory dendrites (cilia) bathed in a fluid, called the sensillum lymph. Pheromone molecules are thought to diffuse through the pore tubules in the cuticular wall and across the sensillum lymph to reach receptors located in the cilia (3-5).The pheromone-binding protein (PBP) is a 16-kDa watersoluble protein, identified in the sensilla of male Antheraea polyphemus by its ability to bind pheromone without metabolizing it (6). This finding and the protein's enormous 10 mM concentration in the sensillum lymph led to the suggestion that it serves to solubilize the extremely hydrophobic pheromone molecules (3-7).In an attempt to better understand the structural and functional properties of the PBP, we undertook experiments to further characterize the protein. Here

Hypotheses on general olfaction can be divided into two broad groups: those that predict the existence of olfactory-specific olfactory receptor proteins and those that do not. Recently, much attention has been paid to the discovery of an odorant-stimulated adenylate cyclase in purified olfactory cilia. This finding has, for the most part, been accepted as evidence that the former hypotheses are correct. Here we report that frog melanophores, which are nonolfactory in nature, disperse their melanosomes in response to the same types and concentrations of odorants used in the investigations ofolfactory cilia and that pigment dispersion is accompanied by rises in intracellular cAMP levels. The effects show that the existence of a cAMP-based second messenger system in olfactory cilia is not in itself proof of the existence of olfactoryspecific olfactory receptor proteins. Also they explain the basis of Ottoson's pioneering work of 30 years ago on the electrical responses of frog olfactory epithelium to stimulation with alcohols. The results suggest that there could be two mechanisms that are important for the detection of odorants: one based on specific receptors, the other nonspecific, but both working through activation of cAMP.Many cellular processes are mediated by cAMP and recently olfaction has been added to this list (1-3). The sense of smell in vertebrates is a property of the olfactory neuroepithelium. While this epithelium contains several types of cells that are important for olfaction, the bipolar receptor neurons are ultimately responsible for odorant detection. These neurons are physically striking for the tuft of cilia sprouting from the bulbous expansion that marks the end of each dendrite (4). The cilia, which in some animals exceed 100 ,uM in length, form an interlacing meshwork intercalated into mucus covering the epithelium. Because of their physical location the olfactory cilia have long been thought to be the primary detectors of odorants. In support of this premise cilia have now been shown to contain high levels of the GTP binding protein Gs, a cAMP-gated conductance, and an adenylate cyclase that can be activated by incubation of the cilia with odorants applied at concentrations in the range of 100 to 250 ,uM (1)(2)(3)5). However, the molecular nature of olfactory receptors themselves has remained obscure.Many proteins have been suggested as candidates for being olfactory receptors (6-9). That no specific receptor proteins may be required for general olfaction has also been suggested (10-12). We decided to determine whether odorants could activate adenylate cyclase in cells that were neither neuronal nor olfactory in nature. Melanophores were chosen because activation of adenylate cyclase results in a rapid and easily observable change in phenotype.Melanophores, which are found in many vertebrates, contain organelles called melanosomes that are filled with the dark brown pigment melanin. The melanosomes can be moved either centripetally or centrifugally within the cells in response to...

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Hormonal alterations are consequences, as well as causes of some pathological abnormalities developing in patients with chronic renal failure (CRF). The most important differences occur in the hormones regulating calcium metabolism: serum levels of parathormone and calcitonin increase, while those of active vitamin D metabolites are absent or undetectable. Other parts of the endocrine system are also involved. Hyperprolactinaemia (Gomez, Cueva, Wauters and Lemarchand-Beraud 1980), hypergonadotrophic hypogonadism (Sy Lym and Fang 1975), hypersomatotropinaemia, sometimes hypercorticotropinaemia, various alterations in the hormones of the thyroid, hyperinsulinism, hypergastrinism (Bonomini, Orsoni, Stefoni and Vangelista 1979) have been described. Serum levels of adrenocortical hormones: Cortisol and aldosterone (Bonomini et al. 1979) as well as D and D-s (Sziics and Bodrogi 1980) seem to be normal.Male impotence is a disabling and poorly tolerated complication in CRF patients on maintenance haemodialysis (MHD). In this condition a causative role was suggested among others of increased serum PRL and/or decreased serum T levels. On the other hand, some data point to the trophic role of PRL on the adrenal androgen (D or its sulphate, D-s) production (Seki and Kato 1981).To study the relationship between the above mentioned hormones and clinical signs serum PRL, T, D and D-s levels were detected in male CRF patients on MHD, before and after treatment with bromocriptine (Br, Parlodel, Sandoz, kindly supplied by Sandoz AG, Basel). Material and MethodsSeven male patients were studied (aged 26-50, mean 37,8) with CRF on MHD 3 times weekly. Unheparinized blood was withdrawn just before dialysis and the sera were stored at -25°C until determinations. Radioimmunological methods were employed for determinations of PRL (Prolactin-Ter, Serono), T (Bodrogi and Feher 1980), D {Abraham, Buster, Kyle, Corrales and Teller 1973) and D-s (Bodrogi and Feher 1982. Patients did not have hormonal treatment but in 4 cases hypertension was treated with alfa-methyldopa (Dopegyt, E.Gy.T., 750 mg), a drug which enhances serum PRL level in some CRF patients (Gomez et al. 1980). Parlodel 2.5 mg twice daily was given for at least 3 weeks and thereafter hormonal determinations were repeated. Inquiries about sexual complaints were made before treatment, at the time of hormonal determinations and 2 months later, still on Br. Results and DiscussionBefore treatment serum PRL levels were elevated, while T was subnormal in 2 patients and normal in the other ones. Serum D and D-s levels were normal, though often in the low normal range (Table 1). Various sexual complaints (potency, libido, erection, pollution) occurred in each person. As a result of Br therapy, PRL decreased significantly (T: 3.41 P < 0.05), became normal in 3, remaining only slightly elevated in the others. Serum T, D and D-s (except T elevation in one patient) remained practically unchanged. Sexual complaints improved in 5 patients. There was a weak correlation between improvement in ...