Characterization by cytofluorometry of the different types of adenohypophyseal cells in the rat

The different antehypophysical cell types which synthetize and release somatotroph (GH), corticothroph (ACTH), gonadotroph (LH-FSH) and lactotroph (PRL) hormones were analysed. The experiments were performed on hypophyses from five groups of animals: adult males, 14 days-old female, adult females, gestating adult females and lactating adult females. The cells were analysed by immunofluorescence using flow cytometry. For each of the hormones studied, there was a characteristic spectral distribution of cells. The evolution of cell size and granular content with respect to sex and physiological state of each group was studied by the analysis of diffused light. Small, slightly granular cells represented 50% of the cell population in males and 14 day-old females but only 8% in gestating or lactating females. The study of the cell cycle showed the presence of dividing cells in the population of large, granular cells from gestating and from lactating females. No features of cell division were observed in the population of small, slightly granular cells. This study indicates the potential value of multiparametric analysis in the separation of pure sub-populations of antehypophysial cells.     

Absence of Turner stigmata in a 46,XYp-female

A 46,XY female patient with streak gonads and a large deletion of Yp is described. The deletion included the Y chromosomal genes SRY, ZFY, and RPS4Y. The patient did not display any Turner stigmata, such as webbing of the neck, cardiac or other abnormalities. The findings argue against an important role of RPS4Y in the prevention of Turner stigmata in males and are consistent with a role of SRY in testis differentiation in humans.     

Prolactin modulates steroidogenesis by rat granulosa cells: I. Effects on progesterone

Either testosterone or follicle-stimulating hormone (FSH) stimulates progesterone secretion by granulosa cells from rats but the combination of the two hormones increases progesterone production in a synergistic manner. We have investigated the effects of graded doses of prolactin (0, 0.02, 0.2, 2, or 10 micrograms/ml) alone or in combination with testosterone (0.5 microM), FSH (300 ng/ml), or FSH + testosterone on progesterone secretion by granulosa cells at two stages of differentiation. Relatively undifferentiated granulosa cells from immature, diethylstilbestrol-treated, hypophysectomized (HPX) rats were cultured in defined (serum-free) medium for 3 days. More highly differentiated granulosa cells were obtained on the morning of proestrus from the preovulatory follicles of 30-day-old rats induced to undergo an estrous cycle by injection with 4 IU pregnant mare's serum gonadotropin; these cells were cultured in medium containing 10% fetal bovine serum. Prolactin alone did not enhance the negligible secretion of progesterone by cells from HPX rats, but increased progesterone secretion by cells from proestrous rats. Prolactin significantly enhanced the stimulatory effects of testosterone or FSH alone on cells from both HPX and proestrous rats. When cultures containing both FSH + testosterone were treated with prolactin, progesterone secretion by cells from proestrous rats was significantly enhanced, whereas secretion by cells from HPX rats was significantly depressed. Therefore when cells from HPX rats were cultured with both FSH and testosterone, the direction of the effect of prolactin was reversed from that observed with prolactin + FSH or testosterone alone, and from that observed when cells from proestrous rats were cultured with prolactin + FSH + testosterone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Haemolysis of rabbit erythrocytes by a lectin from the seeds of<Emphasis Type="Italic">Croton tiglium</Emphasis>

The kinetics of haemolysis of rabbit erythrocytes byCroton tiglium lectin was studied as a function of concentration of the lectin and erythrocytes. The length of the prelytic period decreased with increasing lectin concentrations, indicating that the secondary events at the membrane which follow the binding of the lectin to cell surface carbohydrate receptors are accelerated at higher surface concentrations of the lectin. The rate or extent of haemolysis was not affected by the inclusion of ions like K⁺, Ca²⁺ and Mg²⁺ in the medium or by the substitution of ionic medium by a non-ionic medium. The inhibition of haemagglutination and haemolysis of rabbit red cells byCroton tiglium lectin by antilectin rabbit serum was observed. A possible mechanism of haemolysis by the lectin is discussed.     

Plant lectins specific for N-acetyl-β-D-galactosamine

N-Acetyl-D-galactosamine in β-linkage being ubiquitous in cell surface glycoproteins, their interaction with lectins specific for this sugar moiety may be a significant event in cell adhesion phenomena. This article discusses the common β-N-acetyl galactosamine-specific lectins, with particular stress on the lectin from winged beans (Psophocarpus tetragonolobus).