An isolierten menschlichen Fettzellen wurde die Beziehung zwischen lipolytischer Aktivität und der Fettzellgröße untersucht. Dazu wurden bei 16 chirurgischen Patienten mit unterschiedlich ausgeprägtem Unter-bzw. Übergewicht intra operationem subkutanes Fettgewebe aus dem Abdominalbereich entnommen und mittels Kollagenase die Fettzellen isoliert. Die spontane und durch Adrenalin induzierte Lipolyse wurde nach einstündiger Inkubation der Fettzellen in albuminhaitigern Krebs-Ringer•Bikarbonat-Puffer gemessen. Als Parameter der Lipolyse diente die Glyzerin-und Fettsäun•nproduktion. Die Ergebnisse wurden nicht, wie bisher üblich, auf das Gewicht, sondern auf die Zahl und die Volumina der inkubierten Fettzellen bezogen. Die Bestimmung der Zellvolumina und der Zahl der inkubierten Fettzellen erfolgte durch Auswertung photomikroskopischer Aufnahmen der isolierten Fettzellen. Folgende Resultate wurden gewonnen:

Calcium ions are of irnportance for the function of every cell in the organism, and this applies also for the fat eells. In incubated slices of rabbit adipose tissue, ACTH-or epinephrine-stirnulated Iipolysis was accompanied by an increase in.tissue calcium (A/cgün and Rudman 1969). Werner and Löw (1973, 1974) investigated the effects of the hormones of calcium homeostasis, parathyroid hormone and calcitonin, upon lipolysis of incubated rat adipose tissue pieces and demonstrated that parathyroid hormone induced a 3 to 5 fold inerease in glycerol release, which was aecompanied by enhanced calcium aeeumulation in the tissue, whereas calcitonin exerted opposite effeets. As the question remained open whether these meehanisms were instrumental in the human organism, too, the influences of parathyroid hormone and of calcitonin upon incubated slices of human adipose tissue were studied.

Tbe lipolytic activity of some fractions isolated from porcine pituitary glands was studied in vitro on isolated rat fat tissue. As the check.ed fractions showed cortiootropic activity also, their lipolytic effect was oompared with that of ACfIl For the pituitary gland fraction with the highest lipolytic efTect it oould be shown that tbis lipolytic activity was not due or only to a small extent due to a oontamination with ACfH.Horm. Metab. Res. 3: 167-170 (1971) K e y -W 0 r d s: Lipolytic Hormone -Adrenocomcotropic Hormone

From the recently described lipolytically active pituitary g1and fraction P IV we isolated three other fractions with different lipid mobilizing effects. These fractions were checked far their corticotropic activity as ACfH belongs to the most active lipolytic hormones. The applied bioassay for ACfH was based on the determination of the corticosterone increase in the adrenal vein blood of hypophysectomized rats. All of the isolated fractions showed corticotropic activity.Horm Metab. Res. 2: 333-337 (1970) K e y -W 0 r d s: Lipolytic Hormone -Purification Procedure -Corticotropin -ACTH-Bioassay_

111e lipolytic activity of erude hog pituitary ex traets was studied on isolated fat cells of rats. 111e lipolytic activity as measured from the release of glycerol was compared to the standard pharmacologic agent l-norepinephrine. All pituitary fractions stimulated Iipolysis. 111e fraction with the highest Iipolytic activity could be separated chromategraphically as weil as by gel-ftltration to further lipolytic active components. An increase of lipolytic activity with reference to weight, could not be achieved employing those separation methods as earlier described by our group.