Wolf-Georg Forssmann

Urodilatin (CDD/ANP‐95‐126) is not biologically inactivated by a peptidase from dog kidney cortex membranes in contrast to atrial natriuretic peptide/cardiodilatin (α‐hANP/CDD‐99‐126)

Atrial natriuretic peptide (CDD/ANP‐99‐126) is rapidly inactivated by a membrane preparation from dog kidney cortex. Inactivation occurs by cleavage of the ring structure in the position between Cys‐105 and Phe‐106. A unique proteolytic product separated by HPLC on reverse‐phase column appears as a single peak which elutes prior the intact peptide. In contrast, CDD/ANP‐95‐126 (urodilatin) which is released from the kidney is not destroyed by proteolysis using an identical membrane preparation.

Immunohistochemical and chromatographic studies of peptides with tachykinin-like immunoreactivity in the central nervous system of the lamprey

The distribution and chemical properties of compounds with tachykinin-like immunoreactivity (TK-LI) in the spinal cord and brain of lampreys (Lampetra fluviatilis and Ichthyomyzon unicuspis) were investigated by means of immunohistochemistry and various chromatographic methods combined with radioimmunoassay. The distribution of TK immunoreactive fibers in the lamprey spinal cord was investigated with 13 different TK antisera which gave positive staining in pilot experiments. The antisera were raised against substance P (SP) (n = 6), physalaemin (PHY) (n = 1), neurokinin A (NKA) (n = 2), kassinin (KAS) (n = 2) or eledoisin (ELE) (n = 2). Pre-incubation of these antisera with their corresponding TKs abolished or reduced the immunostaining. Four different patterns of distribution were found with the 13 antisera, and they did not seem to be related to the TKs against which the antisera were raised. The different patterns could be explained by assuming the presence of the three different TKs. Six different antisera, raised against SP (n = 2), KAS (n = 2) or ELE (n = 2), were used for radioimmunoassay. The TK-LI material eluted as several separate components in various chromatographic systems. The central nervous system (CNS) of the lamprey did not contain measurable amounts of SP, NKA, neurokinin B (NKB), KAS or ELE. The present data imply that the lamprey CNS contains at least three different TKs probably different from SP, PHY, NKA, NKB, KAS or ELE; these are possibly new, not earlier described TKs. The three hypothetical TKs differ in their distribution.

A multihormonal tumor of the pancreas producing neurotensin

In a pancreatic adenoma approximately 78.7% of the endocrine cells reacted specifically with antisera to neurotensin, 17.5% to gastrin, 2.8% to pancreatic polypeptide, and 1% to glucagon. The electron microscope revealed that the majority of the endocrine cells were N-cells—morphologically similar to the ileal N-cells which are known to represent the neurotensin-producing cells. Neurotensin was extracted from the tumor and identified by Sephadex, ion-exchange, and high-pressure liquid chromatography. Gastrin, pancreatic polypeptide, and glucagon cells were also identified by the electron microscope; the peptides were extracted and demonstrated by chromatography. The serum concentrations of these hormones were elevated. After total gastrectomy which was necessary because of Zollinger-Ellison syndrome, a jejunoesophageal alkaline reflux, reaching the upper esophagus appeared. As intravenous infusion of synthetic neurotensin in rats caused an increase of luminal enteric pressure, it is suggested that severe jejunoesophageal reflux after gastrectomy may be a clinical feature of a neurotensinoma.

Isolation of bovine cardiodilatin by fast protein liquid chromatography and reversed-phase high-performance liquid chromatography

Cardiodilatin (CDD), a polypeptide exhibiting vasorelaxant and diuretic natriuretic bioactivity, was isolated from bovine atria. The isolation procedure reported here is different from that originally used for the purification of porcine and bovine CDD. Instead of cation-exchange chromatography on Fractogel TSK-CM 650 S and several purification steps on different high-performance liquid chromatographic (HPLC) columns, it is now possible to obtain CDD-88 by an automated fast-protein liquid chromatography system for repeated injections and a motor valve as fraction collector and only one final step of reversed-phase HPLC on a TSK-ODS-120T column.

Atrial granules in the dog heart after cardiac denervation

SummaryBecause the increase in sodium excretion during left atrial distension in conscious dogs is abolished after chronic cardiac denervation, we have investigated whether this is a result of the disappearance of specific atrial granules. Electron microscopy and light-microscopical and ultrastructural immunohistochemistry of canine atria show that atrial granules displaying immunoreactivity for cardiac hormones of the cardiodilatin/atrial natriuretic polypeptide (CDD/ANP) family are still present in denervated left and right atria, although reduced in quantity. It is concluded that the “atrial-induced natriuresis” is not only related to the existence of specific atrial granules. The functional link between atrial-induced natriuresis provoked by atrial distension and the release of atrial polypeptide hormones remains uncertain because the denervated heart can secrete CDD although the diuretic-natriuretic effect is altered.

Morphology and innervation of a testicular 'rete mirabile' in the guinea-pig.

SummaryThe morphology and innervation of the testicular artery and pampiniform plexus of the guinea-pig was investigated using light immunohistochemistry as well as transmission and scanning electron microscopy. The tortuous, spiraled testicular artery embedded within the epididymal fat pad is totally encompassed by a thin-walled sinus-like labyrinthine structure comprising the pampiniform plexus. Characteristic features of this lacunar system are: 1. Endothelial bridges, strands or trabeculae of various length, width and thickness which project into the lumen, occasionally branch, and attach to the opposite or adjacent area of the venous wall. 2. A frequent discontinuous smooth muscular layer.Nerve fibers were localized by use of antibodies against dopamine-β-hydroxylase (DBH-IR), neuropeptide Y (NPY-IR), and substance P (SP-IR). A great abundance of NPY-IR and DBH-IR axon bundles are seen surrounding the testicular artery. Fibers emanating from this dense plexus travel into the interstitium to finally innervate the walls of the sinus-like system, including the cross-luminal trabeculae. In contrast, larger varicosities are distinctive for SP-IR fibers which are also located at the media-adventitia border of the arterial and venous walls but to a far lesser extent than that seen with DBH-IR or NPY-IR.The axon varicosities supplying the arterial and venous walls contain a heterogeneous population of various types of vesicles, mostly including small agranular and granular ones as well as large granular vesicles of various size and density. The most conspicuous feature concerning the innervation pattern of the venous wall is the occurrence of numerous neuroendothelial contact zones.The findings of the investigated ‘rete mirabile’ are discussed with respect to rheology and temperature control for the maintenance of normal spermatogenesis.

Studies of the guinea pig epididymis

SummaryThe guinea pig epididymis is subdivided into seven zones. The ultrastructure and morphology of the principal cells in these zones is analyzed. The position, shape and content of the nuclei are variable along the length of the epididymal duct. Features characteristic of absorptive activity, such as micropinocytotic caveolae, vacuoles, and multivesicular bodies are of high concentration in zone IV and VI. The Golgi apparatus, rough endoplasmic reticulum and secretion granules are organelles and inclusions implicated to secretory functions and in this study are not found in the following concurring amounts within the principal cells of the seven zones: the Golgi apparatus exhibits a trend of increase from zone II to zone VII while the rough endoplasmic reticulum decreases. Secretion granules, though, are detected only in zones II and III, not only in the supra-, but also in the peri-and infranuclear regions. This possibly implies an exocrine secretory functions. Lamellar whorls and profiles of tubular smooth endoplasmic reticulum are concentrated in the supranuclear and adluminal regions of zones I, II and VI. A high concentration of large lipid droplets is a consistent feature of the perinuclear region of zone II. Mitochondia and lysosomes are detected in relatively large amounts along the epididymal duct. The correlations of these morphological characteristics with respect to their possible functional role are discussed.